Remeis-Wiki - User contributions [en]

Travel

2025-05-06T15:05:02Z

Kirsch: /* Application for business travel */

[[Category:Internal]]

This page documents how to apply for business travel and hand in the reimbursement with the online tool accessible through [https://www.mitarbeiterservice.bayern.de/ authega]. This requires you to have an account set up. If you sign up for the first time you will be send a letter (! yes, physical letter, this can take some days) with information for the login. For further logins it is best to use a certificate file with a password.

Once logged in you can access the travel management (Reisekostenmanagement, RMS) and enter the necessary information there. Certain numbers are tied to the observatory and will always be the same, they are documented below. '''Note:''' When selecting the institution (Beschäftigungsbehöde) do '''not''' use the Remeis-Observatory or any other smaller body. Instead use the general FAU entry with the number '''1519016'''! In the field '''Kapitel''' enter '''1519'''!

More information for the general setup are in the [[:Media:introduction_bayrms.pdf|introductory slides]] (unfortunately only in German, but mostly with images so you should at least get the right buttons from it).

== Application for business travel ==

Some notes on filling in these forms:

=== Travel days (Reisetage) ===
On every day, you need to input the start and end of your "business".
If you are, say attending a conference starting Monday at 2 PM and ending on a Friday at noon, your times should look like this:
* Monday: Start at 14:00, end at '''23:59'''
* Tue-Thur: Start at '''0:00''', end at '''23:59'''
* Fri: Start at '''0:00''', end at 12:00

The point here being that you are still there "on business" even outside the main conference hours.

=== Mitzeichner (Signatory) ===
This needs to be your boss, who will then forward it to P6.

== Handing in reimbursement ==

== List of project funds ==

Below is a list of project funds that you travel might be payed from. '''Before submitting your reimbursement form ask your supervisor what project to use! Every time!'''

{| class="wikitable" style="margin:auto"
|+ Project numbers
|-
! Name !! Erweiterung !! Titel !! AWK !! Kostenstelle
|-
| DLR 50 OR 2309 (VF-ULX) || 7401 171 || 547 41 || || 1415151100
|-
| DLR 50 OO 2417 (THESEUS) || 7401 182 || 547 41 || || 1415151100
|-
| DLR 50 OR 2410 (VF-XMM Aafia) || 7401 186 || 547 41 || || 1415151100
|-
| DLR 50 QR 2503 (eROSITA) || 7401 188 || 547 41 || || 1415151100
|-
| DLR 50 QR 2508 (ATHENA) || 7401 191 || 547 41 || || 1415151100
|-
| DLR 50 OO 2507 (AXIS) || 7401 196 || 547 41 || || 1415151100
|-
| || || || ||
|-
| DFG WI 1860/17-2 (eRO STEP 1, P5) || 7458 208 || 547 41 || || 1415151100
|-
| DFG WI 1860/19-1 (eRO STEP 1, P6) || 7458 046 || 547 41 || || 1415151100
|-
| DFG WI 1860/20-1 (FOR 5195, P2) || 7458 065 || 547 41 || || 1415151100
|-
| DFG WI 1860/21-1 (eRO STEP 2, P7) || 7458 209 || 547 41 || || 1415151100
|-
| || || || ||
|-
| DFG overhead WI bis 2022 || 5002344 || 547 40 || PPS || 1415151100
|-
| DFG overhead WI ab 2023 || 150234 || 547 40 || PPS || 1415151100
|-
| || || || ||
|-
| ESA (DALI) || 7402 745 || 547 41 || || 1415151100
|-
| Wlms Altprojekte || 7402 304 || 547 41 || || 1415151100
|-
| ETI Förderung || 5500 245 || 547 41 || || 1415151100
|-
| || || || ||
|-
| DFG SA 2131/13-2 (eRO STEP 2, P1) || 7458 204 || 547 41 || || 1415150013
|-
| DFG SA 2131/14-2 (eRO STEP 2, P2) || 7458 205 || 547 41 || || 1415150013
|-
| DFG SA 2131/15-2 (eRO STEP 2, TP Z) || 7458 206 || 547 41 || || 1415150013
|-
| DFG SA 2131/18-1 (eROSITA Galaxien) || 7458 168 || 547 41 || || 1415150013
|-
| || || || ||
|-
| DFG overhead SA (Altprojekte) || 7459 704 || 547 41 || || 1415150013
|-
| DFG overhead SA bis 2022 || 5002391 || 547 40 || PPS || 1415150013
|-
| DFG overhead SA ab 2023 || 0150178 || 547 40 || PPS || 1415150013
|-
| || || || ||
|-
| DFG SA 4388/2-1 (Saeedi) || 7458 207 || 547 41 || || 1415150013
|-
| DFG MA 11073/1-1 (Mayer) || 7458 221 || 547 41 || || 1415150013
|-
| DFG HE 1356/70-2 (Heber) || 7458 225 || 547 41 || || 1415150000
|-
| || || || ||
|-
| 73er Titel || 061 000-6 || 547 40 || FuL || 1415150000
|-
| 72er Titel || 806 3141 || 547 41 || || 1415150000
|}

Additionally you need to specify the kind of expense (Kostenart): 685000. If the AWK is empty in the table above, do not put anything in the '''Info 1''' field. Otherwise add the given symbol.

== ''OUTDATED!'' Business and private travels ==

If you intend to combine a business trip with a vacation to save money or just because of the occasion, you need to observe a couple of issues:

* first of all, combining business and private travel is in principle nothing that the university likes
* you *need* to get the private travel authorized on the travel request form, i.e. you need to state *both* on travel request form
* obviously you will not get any reimbursement for the private part of your trip, or any extra expenses arising from your vacation
* to get reimbursement for your business part of the trip, you need to document what the business part alone would have cost. In detail this means that you need to document:
* fictitious cost of flights/train tickets/rental car/etc for the business part of the trip
* fictitious cost of flights/train tickets/etc to and from the business destination of the trip
* nevertheless you also obviously need to state your actual cost (flight tickets etc).
* the university will reimburse you only the *lesser* of your actual cost and the fictitious cost!\\ This means that if your flight would have cost 1000 Eur, but because you stayed longer for private reasons (i.e. over the weekend) and the actual flight is cheaper like 700 Eur, the university will only reimburse you 700 Eur.

Furthermore apart from the reimbursement by the university, you have also to consider the taxes: the fiscal authorities might consider such a combination of business and private trip entirely private and therefore the reimbursement as additional income. So far,
this has never happened in Bamberg to Jörns knowledge, but in principle tax
regulations state that for a trip to count as a business trip, the
business portion must outbalance the private portion. To give an
example: a 3d observing run in Australia followed by a 2 week vacation
there would probably not be seen as a business related trip (even if it
was!), even though the university would reimburse you for your flights
and the 3d per diem.
((Based on a FAQ Email sent by Jörn to allusers on April 4, 2011))

Remeis English Checklist

2024-12-18T15:44:03Z

Kirsch:

====== The Remeis English Checklist ======

(by J. Wilms and K. Pottschmidt)

'''''First of all and most importantly:'''''

* did you read the instructions to authors of the journal? If you are working on a thesis, did you read those of [http://www.aanda.org/doc_journal/instructions/aadoc.pdf Astronomy and Astrophysics]?
* did you read appendix A of the [https://journals.aps.org/files/rmpguide.pdf instructions to authors] of Rev Mod Phys?

==== Punctuation ====

* did you remove all commas before "that"?
* did you end your footnotes and captions with a full stop (".")?
* did you make sure that your use of "data" is correct and uses plural verbs?
* did you make sure that you do not have a ":" anywhere before an equation, but that your equations are seen as part of your sentences?
* did you make sure that you have commas surrounding "i.e." and "e.g."?

==== Spelling and Word usage ====

* do you consistently use either British or American spelling?
* did you run a spell checker over your manuscript? For TeX, use "ispell" or the built in spell checker in emacs.
* did you make sure not to use country prefixes in addresses in the author list?
* did you avoid passive voice as much as possible?
* did you make sure that you are //not// using "The found results are..." and similar German constructs in your text?
* did you make sure that everything in your text that is not your original result is accompanied by proper citations?
* did you make sure that you distinguish between "estimate" and "estimation" by replacing all "estimation" with "estimate"?
* did you replace all uses of "exemplary" by "example"?
* did you use "short" for length intervals and "brief" for time intervals? (but note that "short of duration" is correct)
* did you replace all uses of "the actual value" by "the real value"? (if you are German, "actual" does not mean "aktuell"!)
* did you remove all uses of "hence" and "thereby"?
* did you make sure that you use "however" as sparingly as possible?
* did you make sure that you did not use "the equation reads..", but rather used "the equation is..." or "the equation is given by..."?
* did you avoid split infinitives? ("to boldly go..." is wrong; yes, in many cases split infinitives are ok in current English, but they tend to be so often used wrongly by non-native speakers that it is best to avoid them)
* did you make sure that you distinguish properly between "this" and "these"?
* did you make use of the "Oxford comma", i.e., do you have a comma before "and" in lists?
* did you use "i.e." and "e.g." correctly, i.e., using "i.e." for a specific clarification or definition and "e.g." where you would otherwise use "for example"?
* did you use the IAU recommended year - month - day sequences (2016 March 15)?
* did you make sure that you did not use contractions such as "didn't" or "you're"?
* did you replace "cf." with "see" everywhere since you know that "cf." means "compare"?
* did you ensure that you use "opportunity" where in German you would be using "Chance" or "Gelegenheit" (and did not use "chance"...)?
* did you make sure that the reader will understand what thing you refer to when using "it" rather than naming it?
* did you make sure that all uses of "this" are followed by the object you are referring to?
* did you use "led" rather than "lead" when using the past tense of the verb "to lead"?
* did you reread the manuscript for internal consistency after you added comments from your coauthors?
* did you make sure that your sentences are short (rule of thumb: if a sentence goes over more than three lines it is probably too long)?
* did you check that you did not combine two sentences that could be separate sentences with "and"?
* did you avoid abbreviations as much as possible and only used them when they are really, really common (HST, AGN, XMM,...)?
* did you check that you defined all abbreviations that you used at their first usage? ("...Active Galactic Nucleus (AGN)..." //not// "...AGN (Active Galactic Nucleus)..." )

==== Citations ====

* did you add the journal to all publications where you list the arXiv-reference and not just blindly copy the erroneous ADS bibtex entry?
* did you make sure that you distinguished between arXiv references where a paper is submitted and references where a paper is already accepted by checking the paper author's comment on the arXiv-page for that article?
* did you remove the page number for all ATEL-references downloaded from ADS and changed the journal name to "Astron. Tel." or "ATEL"? (and similar for IAU telegrams)
* did you add editors and the title of the conference publication to all conference publications?
* did you add the publisher and place information (city only) to all books, conference publications, and other book-like publications that you are citing?
* did you check that your references are correct in that you are using ''\citet{biblabel}'' for references in the text and ''\citep{biblabel}'' for references in parentheses?
* did you make sure that none of your ''\citet{..}'' commands refer to more than one biblabel?
* [added by O. Koenig: did you make sure all SPIE references have an address? (you may want to follow this procedure: go to NASA ADS to get bibtex entry (<code>@inproceedings</code>!), put the entry of "booktitle" into "series", put <code>booktitle = procspie</code> (there should be a <code>@STRING{procspie = "Proc. SPIE."}</code> in <code>mnemonic.bib</code>, go to the SPIE webpage of the paper, get the address, and insert it by hand. A MWE could be <code>@INPROCEEDINGS{Doehring2015a, author = {{D{\"o}hring}, T. and {...}, title = "{The challenge of developing thin mirror shells for future x-ray telescopes}", series = {Optical Systems Design 2015: Optical Fabrication, Testing, and Metrology V}, year = 2015, editor = {{Duparr}, A. and {Geyl}, R.}, booktitle = procspie, volume = {9628}, address = {Jena, Germany}, pages = {962809}}</code>)]

==== Typesetting (mainly in TeX) ====

* did you check for missing spaces between values and units?
* did you make sure that all scientific units are typeset in <code>\mathrm</code>?
* did you make sure not to use constructs such as <code>$\mathrm{m}/\mathrm{s}$</code> by using <code>$\mathrm{m}\,\mathrm{s}^{-1}$</code> instead?
* did you make sure that almost all of your error bars are rounded up to only one significant digit rather than following the DIN-norm (which is not applied in astronomical journals)?
* did you make sure that you are not using any positioning commands for the table or figure environment such as <code>\begin{table}[htpb]</code>?
* did you make sure that your tables have captions above the table, and figures have captions below the figure or next to it (where allowed by the style)?
* did you make sure that you use empty lines to denote the start of a new paragraph rather than the ''\\''-command? (use <code>\parindent{0pt}</code> if you do not want to indent paragraphs)
* did you make sure that there are no paragraph endings above or below <code>\begin{equation}...\end{equation}</code> by ensuring that there is no empty line above or below the ''equation''-environment?
* did you make sure that you are not using <code>$\frac{a}{b}$</code> in normal text, but use <code>$a/b$</code> instead?
* did you make sure that you are not using the <code>displaymath</code>-environment and that all equations are numbered?
* did you make sure that all of your sections, subsections, paragraphs and so on are numbered?
* did you avoid any and all uses of <code>\bf</code>, <code>\it</code>, <code>\sl</code>, or <code>\em</code> and use the proper commands <code>\textbf</code>, <code>\textit</code>, <code>\textsl</code>, and <code>\emph</code> instead?
* did you use the en-dash of TeX for ranges, even if they occur in math, by using <code>--</code> in text mode rather than a minus sign? (that is, did you typeset a range in an equation as <code>$3x$--$5x$</code> or <code>$3x\mbox{--}5x$</code> rather than, erroneously, <code>$3x-5x$</code>?
* did you correctly use the minus-sign and dashes in astronomical source names, where the name contains coordinates and the <q>dash</q> really is a southern declination or Galactic latitude, that is, did you typeset <code>Her X-1</code>, <code>LMC X-3</code>, but <code>GX\,339$-$4</code> or <code>IGR J16318$-$4848</code> (and as a really difficult one: <code>MCG$-$6-30-15</code>)?
** as a side note: When the first part of the source name is a constellation name (e.g., Her X-1) it should be followed by a full space (<code>~</code>), while if the first part of the source name is a catalog (GX, 4U, 2RXS), it should be followed by a half-space (<code>\,</code>).
* did you make sure to typeset hydrogen equivalent columns as <code>$N_\mathrm{H}$</code> rather than $n_H$ or $n_\mathrm{H}$? (note: in astronomy, $n$ denotes a particle density, so it has units of particles per cubic centimeter, while N is a column with units of particles per square centimeter; a certain analysis program uses nH for this parameter, but this does not mean that n should be used in papers).

[[Category:Current Members]]

PhD hat for Ole

2024-02-28T09:51:58Z

Kirsch:

[[Category:Internal]]

Date of defense: 20th of February 2024

Thesis here: https://www.sternwarte.uni-erlangen.de/~koenig/Koenig_Dissertation.pdf

== Science: ==

* Cyg X-1 NICER timing paper
** Model of Cyg X-1 with three Pauls(?) the Photon (Philipp T ((Aafia)&(Martin)))
** Model of NICER as cheese grinder (above bowl of noodles) (Jona)
** Paul comic...

* eROSITA NOVA paper
** eROSITA looking at WD and smoking (Christian)
*** Use kid paper model + Cotton
** Eye of Sauron on WD or eROSITA
** "Fitted by eye"?

==> Which of these is gonna be the center piece? --> Cyg
Combine as one model

* SIXTE Athena simulations
**Perseus Cluster with WFI
** As meme

* Should we try to make comics of Paul the X-ray photon to go around the hat?

== Hobby: ==
* Climbing: Ole-figurine hanging on rope as a tassel, magnets (Aafia)
* Snowy climbing Mountain with bouldering holds(Amy / Philipp 3D printing)
* Remeis Skiing: Digging for lost ski
* A mountain with one side cliff for climbing and another side for skiing (or above)
** Let him dig for skies in something...

* Some references to observatory pool and barbecues
* Wind surfing on Pool? --> board
* Books: LOTR, ...?
* Motorbike: Key in Javier' box?
* Pub quiz
* Running: Marathon relay with MPE in Munich & Valencia

== Others: ==
* Guided tours (& also for kids), meteoroids with magnet, solar system model, ...
* Lab course: Azimuth experiment, theodolite model(Katya)
* One of the first regulars at new ECAP office --> meme

== Travels: ==
* Train model (Frederico) around the hat with pictures next stop Boston
** Some ICE paper models are here, could be printed to small scale: https://www.bahn-kids.de/bastelvorlagen-alle-ice
* Map with toothpicks & images
* Train ride to Spain
* Yosemite, Alps, Frankenjura, Caucasus --> pictures on rope
* Visit of Caltech
* Lots of talks after Nature paper --> calendar with talks (Philipp T)

== Specific incidents: ==
* Living at Bundschuh house getting up early --> meme (Martin)
* NRTA minutes / Paper note / Tassel --> Steven

== Memes & Images: ==
* Alexey: He has a peaked cap from California with name "Mishka" written in russian letters ("Мишка") on it, which also means "a small bear/ Bärchen" in russian. Could this be played out somehow?

* Put images here: https://drive.google.com/drive/folders/1oVE_utvz_lmQm-qpHWHaqFpyqjmAS9DV?usp=sharing

* Climbing Pictures: https://e.pcloud.link/publink/show?code=kZNmgnZfyGpbEccijBwHvbgRfGa9BpiBL07

* Try making it bio degradable

PhD hat for Ole

2024-01-31T15:25:28Z

Kirsch:

[[Category:Internal]]

Date of defense: 20th of February 2024

Thesis here: https://www.sternwarte.uni-erlangen.de/~koenig/Koenig_Dissertation.pdf

== Science: ==

* Cyg X-1 NICER timing paper
** Model of Cyg X-1 with three Pauls(?) the Photon (Philipp T ((Aafia)&(Martin)))
** Model of NICER as cheese grinder (above bowl of noodles) (Jona)
** Paul comic...

* eROSITA NOVA paper
** eROSITA looking at WD and smoking (Christian)
*** Use kid paper model + Cotton
** Eye of Sauron on WD or eROSITA
** "Fitted by eye"?

==> Which of these is gonna be the center piece? --> Cyg
Combine as one model

* SIXTE Athena simulations
**Perseus Cluster with WFI
** As meme

* Should we try to make comics of Paul the X-ray photon to go around the hat?

== Hobby: ==
* Climbing: Ole-figurine hanging on rope as a tassel, magnets (Aafia)
* Snowy climbing Mountain with bouldering holds(Amy / Philipp 3D printing)
* Remeis Skiing: Digging for lost ski
* A mountain with one side cliff for climbing and another side for skiing (or above)
** Let him dig for skies in something...

* Some references to observatory pool and barbecues
* Wind surfing on Pool? --> board
* Books: LOTR, ...?
* Motorbike: Key in Javier' box?
* Pub quiz
* Running: Marathon relay with MPE in Munich & Valencia

== Others: ==
* Guided tours (& also for kids), meteoroids with magnet, solar system model, ...
* Lab course: Azimuth experiment, theodolite model(Katya)
* One of the first regulars at new ECAP office --> meme

=== Travels: ===
* Train model (Frederico) around the hat with pictures next stop Boston
** Some ICE paper models are here, could be printed to small scale: https://www.bahn-kids.de/bastelvorlagen-alle-ice
* Map with toothpicks & images
* Train ride to Spain
* Yosemite, Alps, Frankenjura, Caucasus --> pictures on rope
* Visit of Caltech
* Lots of talks after Nature paper --> calendar with talks (Philipp T)

=== Specific incidents: ===
* Living at Bundschuh house getting up early --> meme (Martin)
* NRTA minutes / Paper note / Tassel --> Steven

=== Memes & Images: ===
* Put images here: *FAU box or something*
* Alexey: He has a peaked cap from California with name "Mishka" written in russian letters ("Мишка") on it, which also means "a small bear/ Bärchen" in russian. Could this be played out somehow?

* Try making it bio degradable

PhD hat Simon

2021-01-26T15:56:03Z

Kirsch:

Simon's defense is planned in a few weeks.

Biggest problem: How to gather all things to put on the hat.
Idea: People that commute between Bamberg & Erlangen (or pass Erlangen) can deliver things. (Max, Jakob, Ralf, ...)

'''Work things''':
* The "Slurm Snail"

'''Private things''':
* Spruz label
* Bierwanderung (A map of a path with breweries? Maybe the "certificate" with stamps?)

[[Category:Internal]]

Phd hat list

2021-01-26T10:12:56Z

Kirsch:

{| class="wikitable"
! Name
! submission date
! defense date
! responsible person for the hat
|-
| Ralf
| End of 2020
|
| Simon
|-
| Simon
|
|
| Ralf
|-
| Max L.
|
|
| David
|-
| David
|
|
| Jonathan
|-
| Dominic
|
|
| Andrea
|-
| Andrea
| 2021
|
| Dominic
|-
| Katya
| 2021
|
| Max L.
|-
| Jonathan
|
|
| Christian
|-
| Christian K.
|
|
| Ole
|-
| Ole
|
|
| Philipp T.
|-
| Philipp T.
| 2023
|
|-
| Jakob
| 2023
|
|
|-
| Steven
| 2023
|
|
|-
| Mirjam
|
| ?
|
|-
| Eugenia
|
|
| Ralf
|-
|}

PhD hat for Sebastian

2018-05-02T14:52:40Z

Kirsch: Migrated from old wiki

A list of ideas for Sebastian's hat.

If you have ideas, please enter them into the list - if you want signing with you name. This is pure brainstorming. No matter how crazy the idea is, write it down!

* FC Bayern logo inside the hat - though this may be slightly to mean (VG)
* something with worms (VG)
* something related to the Beer diploma (VG): put a small beer glass/bottle next to each item on his hat and connect them via a hiking trail (similar to the Messier marathon on Felix' hat), ending in a certificate that declares his finishing as a "unpassender Anlass" (NH)
* his little yellow car (VG)
* "unpassende Anlässe" (VG): sein Abschluss ist ein sehr unpassender Anlass ;) (NH)
* joke-o-meter (VG): kann man ueber eine Feder und die Keyboardtaste, die Matthias mit dem Lachsack belegt hat, eine funktionierende Version bauen, i.e., eine Nadel ueber ein Kreissegment rutschen lassen? (NH)
* something with confidence intervals (VG)
* a model of neutron star or of a Be-NS-system (VG)
* something with geocaches (MO)
* is the joke activity correlated to the winning/losing of matches of the 1.FCN? (Might not be an idea for the hat but maybe still an interesting question?)(MO)
* something related to one of his nice word-jokes like "normal cone / sili-cone" http://weknowmemes.com/generator/uploads/generated/g1335238078365992068.jpg, "Ge-Nie", and my most favourite: "Verstauchen" which is very much him! :) (TB)
* another Wortspiel with a picture of his boyfriend and the letters "Apostler" (TB)
* a small plastic goal with a display-panel above showing 1:0 for 1.FCN : 1.FCB and playing "oleee, ole ole oleee" or whatever Nemberch sings in the stadium (TB)
* the hat should include a "Schandmaske" concerning his bad jokes (EL) als Visier zum runterklappen?
* maybe attach a head massaging device to the inside of his hat? see http://www.alasiesta.com/bilder/magic-mind.jpg (MW)
* as seen in Würzburg: a rolling board rebuilt as his car and where we can move him through the library, or the ECAP ;-) (EL, VG)
* Gelbe Laus (because the license number of his car is "lau s" and Spreizblock (VG)
* Fehlerrechnung mit dem Bier-Beispiel
* Geocachen
* Buchstabendreher
* Truckstop (Band)

'' ITEMS DEFINITELY ON THE HAT: TO DO '''

* half o the Nuremberg stadion, audience made out of th photos of us '''Michael & Macarena'''
* ''Laus'' idea '''Victoria'''
* Jokelightcurve and statistics '''Matthias'''
* trash can/toilet paper with papers/faces from Japanese/Indians '''Matthias'''
* Beer''deckel'' '''Christian'''
* quaste made out of worms '''Victoria'''
* little lego figure of Stephan with a Prügel '''Wiebke'''
* 3D model BE star ''' Matthias '''
* little bed with a sleeping Sebastian inside & a window with a ghost '''Natalie'''
* "Müller-Reisen" --> tiny book '''Victoria''' (Burg Rabenstein, Rothenburg, Nördlingen, Fränkische Schweiz, Bierdiplom)
* Board with "unpassender Anlass" '''Natalie''' -- 28.10.2013: Graduierung von Sebastian Döge geb. Müller
* Dokto-rand-sign with street and Frau B's car '''Matthias'''
* ALL THE FREE space to be filled up with his puns '''Matthias, Christian, Stephan'''
* innen: cshrc mit Aufruf für FC-Bayern-Logo + Kleeblatt '''Christoph'''
* ZUBEHÖR: Ersatzkordel, Gummiwürmer, Stift für Tafel, Kleber, Klubaufkleber zum Überkleben von Fürth

[[Category:Internal]]

Guided Tours and Public Outreach

2018-05-02T14:46:51Z

Kirsch:

====== Guided Tours and Public Outreach ======

On this pages you can find all informations needed to guide a tour through our observatory for public people.

At least, that's the aim of this page, so please add information if you think its missing!

===== Offering Tours =====

At some point you're perhaps asked to give a tour or if it is possible to have one on a specific date. The latter might occur if Edith is out of her office and her telephone is redirected (usually to one phone in the Knigge room). In those cases you should know __and__ check following things:
* '''Who is asking''' for a tour? \\ If you're on the phone ask for a name and write down the phone number where the person can be called!
* The '''number of people should be between 15 and 25'''. \\ Of course, the boundary conditions depend on the person guiding the tour. In a case of doubt, ask the guide or, if none is found yet, you simply can't promise that there will be a tour! In that case you may offer to look for a guide giving the tour anyway (and call the person back), but again don't make any promises! A list of people offering tours can be found below.
* What is the '''average age of the persons attending''' the tour? \\ That's an important point since the content of a tour differs between children and adults, of course. Furthermore some guides have favorite age groups!
* Carefully check the '''date and time of the tour'''!
** It's most likely to find a guide if the weekday of a tour is '''between Monday and Thursday'''. Friday might work if it is before noon, otherwise people might be on the way into the weekend. In all ohter cases you may offer to look for a guide giving the tour anyway (see the point about the group size above).
** Make sure that there is '''no tour scheduled already'''! For that look into our online calendar (the link can be found below) and on the whiteboard in the copymachine office.
** Related to the last point ensure that there is '''no lab course''' running at the date! The lab course is also marked in our online calendar.
** Usually, a tour will take '''about 1.5 to 2 hours'''.
* Clarify the '''costs for a tour''' beforehand!! \\ Unfortunately, we are '''not allowed to ask for money''' for giving a tour! The only way for getting money is to tell the people that they are welcomed to '''donate money to the [http://foerderverein-sternwarte-bamberg.de/| Foerderverein der Sternwarte]'''. In nearly every case the people or the one asking for a tour will pay something. A rule of thumb is that '''every person donates 3 EUR''' (for children 2 EUR are alright as well). \\ __For your ears only__: 1 EUR per attended person of the donated money will be transfered to the Förderverein (the current treasurer is Ingo, leave the money on his desk with a short note stating the number of people and what kind of a tour this was), the rest is for the guide! There will be a contact phone-number available, best would be to call the contacts-person before the tour to tell them these infos...
* '''Observing with our telescopes''' is possible, of course, but only in case of '''night and cloudless weather'''! No kidding, some people are not aware of these facts... \\ ("The day is too bright to see stars.", "I'm sorry, we can't look trough the clouds.", "The weather forecast is too uncertain, we can't promise.") Please check if someone else has already signed in for one of the telescopes on the day/night of the guided tour!
* If all the above points are clarified '''mark the tour''' \\ in our [http://www.sternwarte.uni-erlangen.de/intern/Kalender/index.php|online calender] and the whiteboard in the copymachine office. You have to be at a machine at the observatory to have access to the online calendar (to be more precisely: you're machine has to have an internal IP-address). \\ The entry into the online calender, besides the date and time, should include "for whom is the tour and the group size, contact person and phone number, name of the guide giving the tour". \\ The whiteboard template is as follows: "date, for whom is the tour, time, guide"

==== Current "staff" ====

The people giving tours currently are:
* Andreas
* Matthias
* Christian H.
* Fe
* Eva
* Simon
* Tobi
* Katha (from Wuerzburg)
* Christina
* Markus
If you're not on the list but interested in giving tours, just do it or ask :-)

===== Preparing a tour =====

'''Before the tour'''
* Shut the doors of all offices in the main building (at least on the ground level) for several reasons: people are not allowed to walk in there and some of us are still working there during tours!
* Remove the northern hemisphere from the model of the inner solar system located in the entrance hall (you may put it into the Knigge room)
* Switch the lights on you need:
** entrance hall
** meteorite showcase (switch is on the right next to it)
** hallway to the meridian building; here are multiple switches
*** main light: right next to the door of the hallway or the backdoor of the main building (labeled "Meridian")
*** info panels: on the opposite wall to the door next to the blue cupboard
*** showcases and Blinkkomparator: in the cutout box up the few stairs on the right wall close to the library, labeled "Linke Steckdosen"
* In case of observations
** carry the needed oculars into the domes (for observations with the naked eye, the 40cm telescope is strongly recommended)
** do __not__ open the domes (first, it might start raining while nobody is there, and it's more fun for you to let the people do it)
** do __not__ remove the dust covers of the telescopes (wait until the dome has been opened)
** read the [[remeis:start|guide how to operate the telescopes and mountings]]
* In case of showing nice pictures
** make sure enough chairs are available
** switch on the beamer in the library, log into the machine and start your presentation, picture-viewer, ...

'''After the tour'''
* Switch the lights off
* Shut down the telescope mounting, put the dust covers back on and close the domes
* Logout of the used machines and switch the beamer off
* Put on the dust covers of the telescopes in the hallway
* Protect the photo plates on the Blinkkomparator from getting dusty
* '''Move the entry from the whiteboard''' in the copymachine office '''to the list attached to the pin-board''' next to it

===== Giving a tour =====

Each tour has several stations, where you can show things or talk to the people. Useful information and experiences about that is listed below. It might be helpful as well to read the article about [[intern:popular_science:start|popular science]] in case you want or have to (if somebody asks) explain scientific aspects.

==== Welcome speech ====

==== Solar system model ====

==== Meteorite showcase ====

==== Hallway - instrument exhibition ====

==== Outreach Material, Presentations ====
Collected information valuable for guided tours:
''/userdata/data/beuchert/work/teaching/guidedtour/presentation/guidedtour.pdf''

A merger of (picture/video) presentations given at guided tours:
''/userdata/data/beuchert/work/teaching/guidedtour/presentation/guidedtour.odp''

and according videos in
''/userdata/data/beuchert/work/teaching/guidedtour/presentation/videos/''

The promotion video by M. Langejahn (Wuerzburg, AG Kadler):
''/home/langejahn/Public/LNdW.mp4''

Research and activities at Remeis from the radio to the gamma-rays:
''/userdata/data/beuchert/work/teaching/guidedtour/presentation/research_at_remeis.pdf''

==== Picture presentation ====
There are different modes for the beamer (e.g. presentation, videos, graphics etc.) which result in a different appereance of the images. Make sure to select a presentation mode in which the pictures appear in an appropriate brightnes on the screen. (I think "graphics" was a good one).
==== Telescopes in the domes ====
It's nice to show the main mirror to the people so that they can see themselves. To do so, just turn down the telescope in declination. This is only possible for the 40cm as the 50cm-Mount has a mechanical stop.

Sometimes people want to know what we do with the tiny, little telescopes attached on the side of the big ones. Those are guiding-scopes. You can attach a camera to them and let it take pictures of one star. If the star moves (what it shouldn't do) a correction signal is sent to the mount to compensate the movement of the star. Stars can "move" in an image for example due to impreciseness of the mount.

The (dusty) plate in front of the 40cm mirror is called "Schmid-Platte". It is used to improve the imaging of the telescope and to correct several errors of the mirrors like coma and field-curvature. As it is very sensitive to scratching, it won't be cleaned and left dusty. But the dust has hardly any effect on the images als it lays far outside of the focusplane. The optical design is similar to a Ritchey-Chrétien type regarding the capability, but has a spherical main mirror, an aspherical secondary mirror and a lens-corrector (=Schmidt-plate). The price of the telescope and the mount is roughly about 25.000€ alltogether.

The 50cm doesn't have a Schmid-Platte but a corrector (lenses) placed in the OAZ. It has an elliptical main mirror and a spherical secondary mirror (Corrected Dall Kirkham). The price of the telescope and the mount is roughly about 65.000€. The secondary mirror is, compared to the size of the main mirror, significantly larger than the 40cm-sec. mirror. This results in a better luminosity an a larger, flat-field which is important for taking images. We can achieve tracking accuracies of about 10min without guiding.

==== Observing ====

[[Category:Internal]]

Guided Tours and Public Outreach

2018-05-02T14:45:39Z

Kirsch: Migrated from old wiki

====== Guided Tours and Public Outreach ======

On this pages you can find all informations needed to guide a tour through our observatory for public people.

At least, that's the aim of this page, so please add information if you think its missing!

===== Offering Tours =====

At some point you're perhaps asked to give a tour or if it is possible to have one on a specific date. The latter might occur if Edith is out of her office and her telephone is redirected (usually to one phone in the Knigge room). In those cases you should know __and__ check following things:
* '''Who is asking''' for a tour? \\ If you're on the phone ask for a name and write down the phone number where the person can be called!
* The '''number of people should be between 15 and 25'''. \\ Of course, the boundary conditions depend on the person guiding the tour. In a case of doubt, ask the guide or, if none is found yet, you simply can't promise that there will be a tour! In that case you may offer to look for a guide giving the tour anyway (and call the person back), but again don't make any promises! A list of people offering tours can be found below.
* What is the '''average age of the persons attending''' the tour? \\ That's an important point since the content of a tour differs between children and adults, of course. Furthermore some guides have favorite age groups!
* Carefully check the '''date and time of the tour'''!
** It's most likely to find a guide if the weekday of a tour is '''between Monday and Thursday'''. Friday might work if it is before noon, otherwise people might be on the way into the weekend. In all ohter cases you may offer to look for a guide giving the tour anyway (see the point about the group size above).
** Make sure that there is '''no tour scheduled already'''! For that look into our online calendar (the link can be found below) and on the whiteboard in the copymachine office.
** Related to the last point ensure that there is '''no lab course''' running at the date! The lab course is also marked in our online calendar.
** Usually, a tour will take '''about 1.5 to 2 hours'''.
* Clarify the '''costs for a tour''' beforehand!! \\ Unfortunately, we are '''not allowed to ask for money''' for giving a tour! The only way for getting money is to tell the people that they are welcomed to '''donate money to the [http://foerderverein-sternwarte-bamberg.de/|Förderverein der Sternwarte]'''. In nearly every case the people or the one asking for a tour will pay something. A rule of thumb is that '''every person donates 3 EUR''' (for children 2 EUR are alright as well). \\ __For your ears only__: 1 EUR per attended person of the donated money will be transfered to the Förderverein (the current treasurer is Ingo, leave the money on his desk with a short note stating the number of people and what kind of a tour this was), the rest is for the guide! There will be a contact phone-number available, best would be to call the contacts-person before the tour to tell them these infos...
* '''Observing with our telescopes''' is possible, of course, but only in case of '''night and cloudless weather'''! No kidding, some people are not aware of these facts... \\ ("The day is too bright to see stars.", "I'm sorry, we can't look trough the clouds.", "The weather forecast is too uncertain, we can't promise.") Please check if someone else has already signed in for one of the telescopes on the day/night of the guided tour!
* If all the above points are clarified '''mark the tour''' \\ in our [http://www.sternwarte.uni-erlangen.de/intern/Kalender/index.php|online calender] and the whiteboard in the copymachine office. You have to be at a machine at the observatory to have access to the online calendar (to be more precisely: you're machine has to have an internal IP-address). \\ The entry into the online calender, besides the date and time, should include "for whom is the tour and the group size, contact person and phone number, name of the guide giving the tour". \\ The whiteboard template is as follows: "date, for whom is the tour, time, guide"

==== Current "staff" ====

The people giving tours currently are:
* Andreas
* Matthias
* Christian H.
* Fe
* Eva
* Simon
* Tobi
* Katha (from Wuerzburg)
* Christina
* Markus
If you're not on the list but interested in giving tours, just do it or ask :-)

===== Preparing a tour =====

'''Before the tour'''
* Shut the doors of all offices in the main building (at least on the ground level) for several reasons: people are not allowed to walk in there and some of us are still working there during tours!
* Remove the northern hemisphere from the model of the inner solar system located in the entrance hall (you may put it into the Knigge room)
* Switch the lights on you need:
** entrance hall
** meteorite showcase (switch is on the right next to it)
** hallway to the meridian building; here are multiple switches
*** main light: right next to the door of the hallway or the backdoor of the main building (labeled "Meridian")
*** info panels: on the opposite wall to the door next to the blue cupboard
*** showcases and Blinkkomparator: in the cutout box up the few stairs on the right wall close to the library, labeled "Linke Steckdosen"
* In case of observations
** carry the needed oculars into the domes (for observations with the naked eye, the 40cm telescope is strongly recommended)
** do __not__ open the domes (first, it might start raining while nobody is there, and it's more fun for you to let the people do it)
** do __not__ remove the dust covers of the telescopes (wait until the dome has been opened)
** read the [[remeis:start|guide how to operate the telescopes and mountings]]
* In case of showing nice pictures
** make sure enough chairs are available
** switch on the beamer in the library, log into the machine and start your presentation, picture-viewer, ...

'''After the tour'''
* Switch the lights off
* Shut down the telescope mounting, put the dust covers back on and close the domes
* Logout of the used machines and switch the beamer off
* Put on the dust covers of the telescopes in the hallway
* Protect the photo plates on the Blinkkomparator from getting dusty
* '''Move the entry from the whiteboard''' in the copymachine office '''to the list attached to the pin-board''' next to it

===== Giving a tour =====

Each tour has several stations, where you can show things or talk to the people. Useful information and experiences about that is listed below. It might be helpful as well to read the article about [[intern:popular_science:start|popular science]] in case you want or have to (if somebody asks) explain scientific aspects.

==== Welcome speech ====

==== Solar system model ====

==== Meteorite showcase ====

==== Hallway - instrument exhibition ====

==== Outreach Material, Presentations ====
Collected information valuable for guided tours:
''/userdata/data/beuchert/work/teaching/guidedtour/presentation/guidedtour.pdf''

A merger of (picture/video) presentations given at guided tours:
''/userdata/data/beuchert/work/teaching/guidedtour/presentation/guidedtour.odp''

and according videos in
''/userdata/data/beuchert/work/teaching/guidedtour/presentation/videos/''

The promotion video by M. Langejahn (Wuerzburg, AG Kadler):
''/home/langejahn/Public/LNdW.mp4''

Research and activities at Remeis from the radio to the gamma-rays:
''/userdata/data/beuchert/work/teaching/guidedtour/presentation/research_at_remeis.pdf''

==== Picture presentation ====
There are different modes for the beamer (e.g. presentation, videos, graphics etc.) which result in a different appereance of the images. Make sure to select a presentation mode in which the pictures appear in an appropriate brightnes on the screen. (I think "graphics" was a good one).
==== Telescopes in the domes ====
It's nice to show the main mirror to the people so that they can see themselves. To do so, just turn down the telescope in declination. This is only possible for the 40cm as the 50cm-Mount has a mechanical stop.

Sometimes people want to know what we do with the tiny, little telescopes attached on the side of the big ones. Those are guiding-scopes. You can attach a camera to them and let it take pictures of one star. If the star moves (what it shouldn't do) a correction signal is sent to the mount to compensate the movement of the star. Stars can "move" in an image for example due to impreciseness of the mount.

The (dusty) plate in front of the 40cm mirror is called "Schmid-Platte". It is used to improve the imaging of the telescope and to correct several errors of the mirrors like coma and field-curvature. As it is very sensitive to scratching, it won't be cleaned and left dusty. But the dust has hardly any effect on the images als it lays far outside of the focusplane. The optical design is similar to a Ritchey-Chrétien type regarding the capability, but has a spherical main mirror, an aspherical secondary mirror and a lens-corrector (=Schmidt-plate). The price of the telescope and the mount is roughly about 25.000€ alltogether.

The 50cm doesn't have a Schmid-Platte but a corrector (lenses) placed in the OAZ. It has an elliptical main mirror and a spherical secondary mirror (Corrected Dall Kirkham). The price of the telescope and the mount is roughly about 65.000€. The secondary mirror is, compared to the size of the main mirror, significantly larger than the 40cm-sec. mirror. This results in a better luminosity an a larger, flat-field which is important for taking images. We can achieve tracking accuracies of about 10min without guiding.

==== Observing ====

[[Category:Internal]]

Structure and Editability of the Lab Manuals

2018-05-02T14:28:31Z

Kirsch: Migrated from old wiki

The lab course manual is located in

/data/git/Praktikumsanleitung.git/

To edit it, you have to use git. A detailed introduction in how to use git can be found [[git:start|HERE]].

The previous path,

/home/praktikum/intern/anleitungen/

now contains a '''read-only''', up-to-date version of the manual, including the pdf file, so if you just want to look up something, you don't have to use git and compile the whole stuff first.

----

== Old version: Two e-Mails from Joern ==
This article contains two e-Mail from Joern Wilms written in September 2009. Although the path is not valid anymore, you can find instructions how to use the git repository and how to write the .tex files, so read this mail carefully!

-----------------------------------------------
Subject: [astro] Anleitungen Praktikum \\
From: Joern Wilms <joern.wilms@sternwarte.uni-erlangen.de> \\
Date: Sat, 05 Sep 2009 22:13:48 +0200 \\
To: astronomen <astronomen@physik.uni-erlangen.de>

Dear all,

the redesigned versions of the lab instructions are now available in

/home/praktikum/intern/anleitungen/anleitung/anleitung.pdf

The instructions are a redesigned version of the instructions used this
spring, collating all materials given out to the students in one large
(100p) booklet (with one exception: error propagation - here I think not
giving out the instructions in advance might be a good idea).

The advantage of this approach is that printing of the instructions is
much easier than before, the instructions look more uniform, some
redundancies were removed. In addition it is much easier now for us to
allow the downloading of the instructions from the www.

I would now like to ask the people responsible for the different
exercises to take a careful look at the new instructions and to apply
any fixes you deem necessary. The cutoff time for printing the
instructions for the first set of students is Saturday evening, 12
September, however, I would like to put a preliminary version of the
instructions onto the www on Tuesday or so, such that those students who
want to prepare for the lab can do so (they have frequently asked us to
give out the instructions beforehand).

Please read the following instructions carefully in case you need to
make changes to a chapter for which you are responsible:
* each subdirectory in /home/praktikum/intern/anleitungen/anleitung contains a texfile of the respective description (e.g., the instructions for the ccd exercise are in ccd/ccd.tex). EDIT THIS FILE AND ONLY THIS FILE. If you want to see what your new chapter looks like, do a <code>pdflatex praktikum</code> in the respective directory. Do NOT use latex to tex this file! The resulting pdf contains a few extra pages. That's fine since we will not be using this file for any printing.
* Do NOT remove ANY of the softlinks in the subdirectory (the aux-files are needed to get cross references to other chapters and the page numbers right). Then take a look at that file, e.g., with kpdf praktikum.pdf
* note: we now use pdftex, i.e., when including graphics, the included files MUST BE in pdf, png or jpg format. ps or eps are NOT allowed. If you cannot produce the supported formats, use pstopdf to convert your ps to pdf.
* To obtain a common look, if you want students to work on a certain exercise, please enclose this in the "aufgabe" environment, i.e., </code>\begin{aufgabe} bla bla bla \end{aufgabe}</code>
* Do not even think about using a Mac to edit any of these tex files, the special characters are incompatible and it takes literally hours to fix things afterwards.

While preparing this version of the instructions I had to fix a
significant number of TeX errors. Please read the following bullet
points carefully to avoid these pitfalls, it will save you significant
time later:

* Since more than 10 years the commands <code>\tt, \it, \bf, \sl, \em</code> have been deprecated for many very good reasons. DO NOT USE THEM. EVER. Instead, use <code>\textbf{bold test}, \textsl{slanted text}</code>, etc. Note that, contrary to <code>\it</code> et al., the <code>\textit</code> et al. commands can be nested. It is perfectly legal, e.g, to write <code>\emph{this is \texttt{emphasize}}.</code> This is one of the many advantages of this approach.
* Many of you seem to think that <code>\\</code> ends a paragraph. That's not true, the double backslash ends a line, paragraphs are ended with an empty line. If you use it in your own texts, what you probably want to do is to set <code>\parindent0pt</code> in the preamble. In other words: unless you are editing a table, you probably never want to use <code>\\</code> unless you REALLY know what you are doing.
* Do not use <code>\mbox</code> and the like in equations. In order to type text, use the <code>\mathrm{...}</code> command or the <code>\text{...}</code> commands instead, they're doing what you really want.
* Never ever for the labs use any positioning specifiers for tables or figures. Let latex do its job, please. (<code>\begin{table}[htp] ...\end{table}</code> constructs; IF you use this in other documents, you probably have the wrong settings for the figure positioning algorithm of latex -- come talk to me in this case).
* Tables have their caption ABOVE the table, Figures have captions BELOW the image.
* Instead of using <code>$$...$$</code> constructs, please use <code>\begin{equation}...\end{equation}</code>. Yes, that's more to type, but it will also give you some time to think about the equation.
* Equations usually form part of a paragraph, for this reason there should not be an empty line before or after the <code>\begin{equation}...\end{equation}</code> construct, and unless an equation ends a sentence, the first character after the <code>\end{equation}</code> should not be capitalized.
* when centering images in figures, do not use a <code>\begin{center}..\end{center}</code> construct as these add unnecessary space. Use the <code>\centering</code> command instead.
* In TeX, the line spacing in a paragraph is determined by the font size that is in place at the end of that paragraph. This means that if you, e.g., want to write a paragraph in a smaller font, you need to tell tex where the paragraph ends. So instead of using <code>{\small this is a small paragraph}</code> use <code>{\small this is a small paragraph\par}</code> (because the newline character after the closing } is a valid TeX character (a space) and the paragraph ends only with the empty line following that character, you will otherwise get the wrong line spacing.

Cheers,
Joern

-----------------------------------------------

Subject: [xray] [astro] editing the lab manuals\\
From: Joern Wilms <joern.wilms@sternwarte.uni-erlangen.de>\\
Date: Fri, 10 Sep 2010 15:49:13 +0200\\
To: astronomen <astronomen@physik.uni-erlangen.de>\\

Dear all,

the lab manuals will be printed and xeroxed on Saturday afternoon, i.e.,
if you are editing the lab manuals, please finish this by noon on Saturday.

Some of you have edited files in <code>/home/praktikum/anleitungen</code>, while
others have used the git.

If you used git, could you please update the above directory by noon
tomorrow and make sure that the tex file(s) in the above directory are
the ones that you would like to see in print?

For the others: I'll do a global commit tomorrow afternoon.

Cheers,

Joern

[[Category:Internal]]

Ocotber 24th: Open House

2018-05-02T14:09:02Z

Kirsch:

On this day the Remeis observatory will celebrate its 125th anniversary. We will open the observatory for the public and offer an interesting program.

It is of particular importance, that many of us are around at that day, especially since there were >500 visitors at our observatory five years ago. Thus, we have set up a basic [http://doodle.com/de6at2excrhbu8ib|Doodle poll], where you can mark time slots when you will be around. If you already know that you can offer one more of the above ideas/points, you can mark this in the Doodle as well.

==== Preliminary Program ====
If a person for any point is still missing and you feel that you can help just edit this page.

{| class="wikitable" style="text-align: left;"
|-
! style="text-align: left;width:20em;" |Program
! style="text-align: left;width:20em;" |Responsible Person(s)
|-
| Kidz entertainment
| Veronika, Katha, Kurt
|-
| ''tour'': Verbindungsgang
| Horst(, Joern)
|-
| ''talk'': Geschichte der Sternwarte
| Uli
|-
| ''talk'': Leben der Sterne usw.
|
|-
| ''talk'': Satelliten & Raumfahrt
| Joern
|-
| ''talk'': Teile des VHS-Kurses
|
|-
| ''talk'': Plattenarchiv
| Heinz
|-
| ''demonstration'': Spektroskopie
| Michael Lemke
|-
| ''demonstration'': Blinkkomparator
| Norbert, Heinz
|-
| ''demonstration'': Radio-telescope
| Eugenia, Fritz
|-
| ''demonstration'': CCDs
|
|-
| ''demonstration'': Kleines Planetarium
| Andreas
|-
| ''observing'': domes
| Michael, Matthias, Christian, Markus
|-
|}

[[Category:Internal]]

Needed functions and libraries

2018-05-02T14:08:36Z

Kirsch: Migrated from old wiki

* '''time and date functions (will be done by Christoph):'''
* ero_date_of_MJD
* ero_date_of_eroday
* ero_date_of_today
* ero_MJD_of_date
* ero_MJD_of_today
* ero_MJD_of_eroday
* ero_eroday_of_date
* ero_eroday_of_MJD
* ero_eroday_of_today

* '''I/O functions (done, testing required):'''
* ero_create_file
* ero_create_fits_tbl
* ero_create_fits_img_2D <- more dimensions required?
* ero_open_file
* ero_open_fits_tbl
* ero_open_fits_img
* ero_close_file
* ero_close_fits
* ero_copy_file
* ero_remove_file
* ero_get_dir
* ero_create_dir
* ero_remove_dir
* ero_file_exists
* ero_check_access

* '''checksum functions (done, testing required)'''
* ero_create_checksum
* ero_update_checksum
* ero_verify_checksum
* <del>ero_remove_checksum</del> (most probably not necessary)

* '''admin notification function(s)'''

* '''warning function(s)'''

* '''logging function(s)'''

[[Category:Internal]]

Ocotber 24th: Open House

2018-05-02T13:58:33Z

Kirsch: Migrated from the old wiki

Category:Atomic Physics

2018-04-11T15:01:27Z

Kirsch: Added internal links

===Atomic Physics Q&A===

===== Nomenclature =====
* [[How_to_identify_ions|Ions: chemistry vs atomic physics vs astrophysics]]
* [[Line_triplet_for_He-like_ions | The He-triplet: RIF vs wxyz]]
* [[What_are_"forbidden"_lines%3F | Forbidden lines]]
* [[Common_lines_in_the_X-rays:_K_α,_He_α,_Ly_α | Common lines in the X-rays: K α, He α, Ly α]]

===== Ionization and Recombination =====

* Autoionization & Dielectronic Recombination
* Photoionization & Radiative Recombination
* Absorption Edges & Radiative Recombination Continua

===== Atomic Databases =====

* [[Atomic_Databases:_General_idea_and_limitations|General idea and limitations]]
* [[AtomdDB:_a_guide|AtomDB: Guide and caveats]]

===== Useful line lists =====

* [[Alex_Markowitz'_Line_List|Alex Markowitz's AGN line list]]
* [[Triplett_energies_according_to_Drake_1988|Victoria Grinberg's script to get more exact triplett line energies based on Drake 1988]]

[[Category:Science]]

GIT -- The Fast Version Control System

2018-04-11T14:53:35Z

Kirsch: Migrated from old wiki

=== What is a GIT Repository? (by Matthias Kühnel) ===

''A repository is a container for project
files and a program, in this case 'git', handles the different versions
of the files and takes care about merging of different file versions.
That means many persons can work on the same project (or more precisely
on the same files) simultaneously without taking care about the
modifications of the other editors. So in principle each editor 'clones'
the repository to his or her local computer, does some modifications and
at last 'pushes' these changes back into the repository. ''

=== Existing Repositories: How to clone and commit changes ===

''The following text is copied from an e-mail from Joern concerning the software scripts of the Remeis observatory. More information one these scripts can be found at [[remeis:software:start|Software at the Remeis-Observatory]].''

==== Get the files ====

If you want to modify scripts, you will first have to get a full copy
of the repository (called a "clone"):

git clone ssh://account@crux.sternwarte.uni-erlangen.de/data/git/aitlib

(same for intscripts, xmmscripts, xtescripts, xspecscripts,
isisscripts, cyclo, fpipe) where account is your account at the
Sternwarte.

Please use the above command EVEN IF YOU ARE WORKING locally in
Bamberg/Erlangen. Do NOT do a clone with the file://-syntax of git to
allow you to work on several machines (since the git push command will
not work properly). Just forget that file://... is an allowed git URL.

==== Committing your changes ====

After doing the clone, edit the scripts and check them. In case you edit the isisscripts: Do not forget to <code>make</code> the isisscripts, i.e. compile your changes into the overall <code>isisscripts.sl</code> by typing
make
in the <code>isisscripts/</code> directory.
You should usually do your changes in smallish steps, i.e., applying a few changes,
checking them, and then committing them to the repository as follows:

git commit filename

OR

git commit -a

(the last if you've made changes to many files). This command will ask
you to enter information for the change log.

CONTRARY to CVS, a commit does not yet make your changes available to
others. This is advantageous, because it allows you to do commits
locally while you're developing a code, and then go back to an older
version once you realize that you've made a mistake. However, let's
assume that you've programmed something that is working and you want
to make it available to everybody. In this case, commit everything as
described above and then do a

git push

(do NOT forget this last command).

After you have committed and pushed your changes, WE STRONGLY
RECOMMEND THAT YOU REMOVE YOUR CLONED REPOSITORY (rm -r repo). The
reason is that experience shows that people often start working on
their "private" versions of the scripts and then either forget to
commit their changes (=nobody else gets access to them) OR they forget
to do regular updates of their local clones and then run into problems
that have already been fixed in the official repository. Access to the
current version of the scripts is better obtained using the approach
outlined below (and implemented on the Remeis machines, for example).

==== Other useful commands ====
* assuming you've already cloned the repository and you want to update it to the newest version, use

git pull

* to obtain a change log of the repository

git log

* to obtain a change log for one file

git log filename

(which will work pretty much for all files, but for some reason does
not work for the intscripts; note that even for the intscripts the
full change log is still available and you can still check out older
versions of the script should you desire to do so)

* to tag one of the commits with a tagname, e.g., to mark the submitted version of your paper as submitted, get the commit id from <code>git log</code> and do

git tag 'tagname' id

where tagname only needs quotes if it contains, e.g., spaces

* to push the tag

git push --tags

* optimize the local git repository

git gc --aggressive
this will optimize the tree of stored local changes, removing intermediate data that are not needed anymore. This makes your local repository dramatically faster and can save significant space. You should run this every now and then (on very active directories probably once a week).

* find out where the repository originally came from before it was cloned:

git remote -v
or for a little more information

git remote show origin
showing the differences between the old and new file:

diff -u new_file old_file
=== Create your own repository ===

'' The following entry is from an email by Matthias Kühnel to Jieun (with additional comments added afterwards) and was intended to explain '''how to create a repository in order to edit a paper together using GIT'''.''

Now we'll create a git-repository for your paper: in your Remeis home
directory create a directory where to store all your repositories in,
such as ~/git (at the moment we'll create only one ;-)). Create a
subdirectory for your paper in there, ~/git/choi2011a for example.
Change into that directory and create an empty repository by
git init --bare --shared
You should get a message like "Initialized empty Git repository in
/home/choi/git/choi2011a/". Add <code>--shared</code> only if everyone in your group should be able to
commit changes.
All in all, this should create a structure of
files and subdirectories in your repository directory. Later your files
will be hidden somewhere in this structure (I'm not sure where to be
honest). The thing is that a bare repository only contains
modifications, that means no whole file, only different pieces depending
on the file version.
Now you have to modify the 'config' file of the repository (//note:// you should not need the following modifications if you initialized the repository with the <code>--shared</code> option), for example
/home/choi/git/choi2011a/config
The file should look like
[core]
repositoryformatversion = 0
filemode = true
bare = true

Your repository is now ready to be used, but empty. So let's add some
files into it!

Create an empty directory somewhere that will contain your paper. We now clone your
(empty) repository into your source directory:
git clone crux:/home/choi/git/choi2011a .
Note that we clone from machine <code>crux</code>, even if we are working on that machine. This approach will make your life easier if you are working on multiple machines in the Remeis cluster. Do not forget the trailing dot!

Now your directory is a clone of the repository. Copy all files and subdirectories that you would like to be part of the repository into the directory and then add these files to git
git add filenames
where filenames can include (relative) paths to files somewhere in the directory tree of your repository.

A general rule for tex repositories for papers is to only add the source code and
*no* compiled or auxiliary files. That means, just add the .tex file,
any used styles (.sty) and images (.pdf, .ps, .eps or whatever). If you have
also isis scripts (.sl) which creates some plots, you may add them also.
Once you have added all necessary files, you have to 'commit' the changes:
git commit -a
Now your default editor should open automatically, where you have to
enter a comment describing the changes (attention: the default editor should be set first in the ~/.cshrc, see [[csh:start|TC shell]]). This
comment will be put into the log. The editor also shows a list of files
which will be added/modified/removed. Please note that this list is for
your information *only*. Any changes to the list have no effect!
After you have entered a comment, quick save the file (if you use jed
Ctrl-X-S) and exit the editor (Ctrl-X-C). You should see something like:
[master 5e91497] your_entered_comment
1_or_more files changed, 3341_or_any_other_number insertions(+), 0
deletions(-)
create mode 100644 a_file_you_have_added
...

In order to avoid being prompted that unnecessary files such as editor backup files (e.g., filenames ending in a tilde or with .bak and other unnecessary files are not part of the repository, you can generate files called <code>.gitignore</code> in your git directories. These files contain descriptions of files which should not be in the repository. a <code>.gitignore</code> file is valid in the current directory and all of its subdirectories. These may contain further <code>.gitignore</code>-files. A good <code>.gitignore</code> for a paper would be:
<nowiki>
#
# git ignore file for TeX files
#
*~
*.aux
*.log
*.bbl
*.blg
*.bak
</nowiki>
Note that after creating the file you will have to add it to the repository! Files that were checked in before the .gitignore exists are not affected by adding the .gitignore, even if the filename is explicitly written down there. In this case, do a git rm [filename] and commit, and afterwards the file will not be checked in again.

That's a summary of the changes, which will be put into the repository
once you have 'push'ed them:
git push origin master
Please note, that the usual command is
git push
without the origin-master-stuff, which has to be done only once if an
empty repository was created!
If you modify previously added files later, you don't have to add them
again, of course. Instead skip the adding command and 'commit' and
'push' the changes directly.

Everybody knowing the path to your repository can now clone it, edit
files and push changes. To update your local copy with the repository
(i.e. to get the changes of somebody else) use
git pull

=== Committing only parts of the modifications ===
''A further functionality Manfred finds particularly useful.''

It has been mentioned above that one can only commit selected files with

git add file1 [file2 ...] && git commit

(Do not use <code>git commit -a</code> in this case. If you really want to commit all changes, there is no need to first <code>git add</code> the files for this next commit.)

It is also possible to <code>git add</code> only parts of the modifications, namely with the <code>-i</code>(nteractive) Option. When I run

git add -i file1 [file2 ...]

and press <code>p</code> for (patch), 1 for the first file, and then hit [Return], I can decide for every changed block ("hunk") in file 1 whether (<code>y</code>) I want to add ("stage") this change to the next commit or not (<code>n</code>). If I want to commit only part of what git considers a "hunk" in first place, I can press <code>s</code> in order to split the current hunk. When I'm done with file 1 or when I quit with <code>q</code>, I can start over from the beginning, e.g. patching the next file.

After the desired hunks have been staged to the index, you run

git commit

as usual, without <code>-a</code>!

=== GIT Config ===

Make sure to update your name and e-mail-address in your home under ''.gitconfig'' like

[user]
email = matthias.kuehnel@sternwarte.uni-erlangen.de
name = Matthias Kuehnel

[[Category:GIT]]

Triplett energies according to Drake 1988

2018-04-11T14:29:43Z

Kirsch: Removed leftover tag

More exact triplett energies than those given in Alex Markowitz's list can be obtained from the Drake 1988 paper

http://adsabs.harvard.edu/abs/1988CaJPh..66..586D

(Note that the references, as always, matters. Other literature references may result in somewhat different lines. The joys of it ...)

In particular, the important part is Table 3. However, instead of direct line energies, it lists things in a somewhat more complex way and in 1/cm, at least for elements He to Kr, i.e., everything that will ever matter in your normal observed spectrum, namely (with thanks to Natalie):

1. column: y (2 ^3P_1 → 1 ^1S_0 or 1s2p 3P1 → 1s2 1S0)
2. column: w (2 ^1P_1 → 1 ^1S_0 or 1s2p 1P1 → 1s2 1S0)
3. column: not important here
4. column: y-z (2 ^3P_1 → 2 ^3S_1 or 1s2p 3P1 → 1s2s 3S1), i.e., they give upper level y minus upper level z
5. column: x-z (2 ^3P_2 → 2 ^3S_1 or 1s2p 3P2 → 1s2s 3S1)

and to obtain the triplet line energies thus

w: 2. column
y: 1. column
x: 5. column - 4. column + 1. column [i.e., (x-z)-(y-z)+y]
z: 1. column - 4. column [i.e., y-(y-z)]

I've written a small script that reads in the data copied from the Drake table and returns the value - please round yourself according to your needs and taking into account the data accuracy:

[[Triplett_line_energies|script]]

This script makes use of [[Ascii_version_of_the_first_35_lines_of_Table_3_from_Drake_19888|this ascii file]] that you will have to copy and name "drake_table3_cm.dat" - this is just an ascii version of the first 35 lines in Table 3 from the Drake paper.

Author --- [mailto:grinberg@space.mit.edu Victoria Grinberg] 2016-25-03

[[Category:Atomic Physics]]

Common lines in the X-rays: K α, He α, Ly α

2018-04-11T14:26:49Z

Kirsch: Added internal link

=== Principle quantum number ===
In a very simple model (the Bohr model), an atom is thought of as a solar system like setup: the nucleus, consisting of protons and neutrons, i.e. the bulk of the mass, is 'orbited' by the electrons on discrete energy levels (orbitals). But unlike the solar system in an atom the attraction is provided by electromagnetic forces rather than gravity. For the orbitals the potential energy increases with distance to the nucleus. The location of an electron in one of these energy levels is denoted by the principle quantum number ''n'' where ''n''=1 corresponds to the innermost orbital.

Often these energy levels are denoted with letters: the energy levels K,L,M,... correpsond to the principal quantum numbers ''n''=1,2,3,... .
Each orbital can hold ''2n2'' electrons.

The state of an atom or ion with the lowest possible energy, is called the ''ground'' state. In the ground state, all electrons are located in orbitals as close to the nucleus as possible. However, electrons can jump between different orbitals. In order to excite an electron to higher levels, it needs to absorb additional energy, e.g., from photons or through collisions. De-excitation of an electron into a lower level can also happen spontaneously by emitting energy in form of a photon.

Note that the Bohr model is a first-order approximation and can only explain the principle quantum number. For a more accurate description of orbitals, quantum mechanics is
essential.

=== Rydberg series in Hydrogen ===
Early on it was discovered that the emission spectrum of atomic hydrogen, the simplest of all atoms, forms a distinct set of spectral series. These series are called the Rydberg series, after the Swedish physicist who discovered a description for these series in the late 1880s. He found that within each series the lines have the same lower level and that the wavelengths of the emission lines can be reproduced by the Rydberg formula

1/λ = ''R'' (1/n'2 - 1/n2)

where n' is the lower energy level, n the upper energy level, and ''R'' the Rydberg constant.
The first handful of series are named after famous physcists:

{| class="wikitable" style="text-align: left;"
|-
! style="text-align: left;width:5em;" |n'
! style="text-align: left;width:15em;" |series
|-
|1 (K)
|Lyman series
|-
|2 (L)
|Balmer series
|-
|3 (M)
|Paschen series
|-
|4 (N)
|Brackett series
|-
|5 (O)
|Pfund series
|-
|6 (P)
|Humphreys series
|-
|}

Spectral lines within a series are designated with Greek letters depending on the upper level, starting with α for n=n'+1, β for n=n'+2, etc. For example, a transition from n=2 to n'=1 would be called Lyman α, or Ly α for short.

=== Generalization of the Rydberg series ===

In case of the hydrogen atom, the nucleus contains only a proton. There are other systems, H-like ions, where also only 1 electron orbits around an albeit heavier nucleus that can contain multiple protons and neutrons depending on the element. These hydrogenic ions display the same series of spectral lines as the hydrogen atom, only at higher energies. Their wavelengths are described by the Rydberg formula modified by a factor of ''Z''2, where ''Z'' is the atomic number, i.e., the proton number of the element.
Starting with about H-like B (Ly α ~250 eV) some of these transitions (especially the Lyman series) fall into the X-ray regime.

It turns out that the Rydberg series can be found in even more generalized ions. Adding a second electron to the ion still results in a pattern of spectral lines very similar to the pattern known from the hydrogenic ions.
But the negative charge of the second electron does screen the positive charge of the nucleus that the first electron "feels" to some extend, effectively lowering ''Z''2. The spectral lines of the He-like system are therefore shifted to somewhat lower energies than the lines in the H-like ion with the same atomic number.

The same is true for basically any number of electrons; if the electron distribution in the orbitals is such that the transitions can occur, the familiar pattern of the Rydberg series can be observed.
However, due to the larger number of electrons, the ions become too complex and the Rydberg formula can no longer reproduce the wavelengths of the corresponding transitions.

==== K transitions ====

Transitions into the K-shell are the equivalent of the Lyman series for multi-electron ions.
This type of transition is the most common transitions in the X-rays. They're easily produced in He-like and H-like ions, but also possible in ions with lower ionization stages. He- and H-like ions are often the dominant (along with bare ions, but bare ions have no electrons to jump between levels and therefore do not produce spectral lines) ionization stage in energetic or hot environments like the vicinity of black holes, since for mid-Z elements the energy needed to produce He- and H-like ions (ionization potential) is fairly low (~4.12 keV to make H-like Ar).

==== others ====

Of course, also the other series besides the Lyman series have their equivalents in multi-electron systems. But since the energy difference between neighboring orbitals decreases with increasing ''n''', already the L-shell transitions (Balmer series equivalent) for the lighter elements move into the UV region. For example, Fe L lines (for various ionization stages of Fe) largely fall below 1 keV, with a limit of about 1.3 keV.

To see M-shell transitions in the X-rays, high-Z elements (e.g., Eu, W) are required. The relative abundance of these elements is so low that they are not typically observed in astrophysics.

=== So what's the difference between K α, He α, and Ly α? ===

K α is a general term denoting the transition of an electron between the n'=1 and n=2 energy levels. Such a transition can happen in any ion, provided there is an initial open space (hole) in the final orbital (in n'=1 for emission, n=2 for absorption). Configurations with such an inner-shell hole can also occur in ions that have electrons in the n>=3 orbitals. Therefore, "Fe K α" (for example) could be a spectral line originating from a n=1-2 transition in '''any''' Fe ion.

To be more specific, for such a transition in helium-like Fe, i.e., Fe with 2 electrons, one could say "He-like Fe K α" - or "Fe He α" for short.

Because of the history of the Rydberg series, a K α transition in a hydrogenic ion is still called Ly α. In case of the Fe example, this would be "Fe Ly α" for H-like Fe.

=== Fine structure ===

The Bohr model and the Rydberg formula only account for the gross structure of the spectra, which only depends on the principle quantum number ''n''. In reality, a number of other effects (kinetic energy relativistic correction, spin-orbit coupling, Darwin term) separate this gross structure into finer levels.
This is referred to as fine structure splitting. It lifts the degeneracy of the levels in //n// and splits the sub-shells into separate energy levels that now also depend on the angular momentum (azimuthal) and total angular momentum quantum numbers ''l'' and ''j''.
Every orbital has ''l''=0,1,...,''n''-1 sub-shells, which in turn split into one to two levels with total angular momenta ''j''=''l''+-1/2. The values of ''l'' are often written in form of letters where ''l''=s,p,d,f,g,... correspond to ''l''=0,1,2,... .
With this fine structure splitting, transitions from ''n''=2 to ''n'''=1 have slightly different energies. For example, the transition 2p1/2->1s1/2 has a slightly lower energy than the transition 2p3/2->1s1/2. Using spectrometers with sufficient spectral resolution, Ly α is seen as two distinct lines Ly α2 and Ly α1.
While these individual lines are still a, e.g., K α type transition, they often have individual "names" to identify them. See, for example, the [[Line_triplet_for_He-like_ions|the He-like system]].

[[Category:Atomic Physics]]

Triplett energies according to Drake 1988

2018-04-11T14:25:16Z

Kirsch: Added internal link

More exact triplett energies than those given in Alex Markowitz's list can be obtained from the Drake 1988 paper

http://adsabs.harvard.edu/abs/1988CaJPh..66..586D

(Note that the references, as always, matters. Other literature references may result in somewhat different lines. The joys of it ...)

In particular, the important part is Table 3. However, instead of direct line energies, it lists things in a somewhat more complex way and in 1/cm, at least for elements He to Kr, i.e., everything that will ever matter in your normal observed spectrum, namely (with thanks to Natalie):

1. column: y (2 ^3P_1 → 1 ^1S_0 or 1s2p 3P1 → 1s2 1S0)
2. column: w (2 ^1P_1 → 1 ^1S_0 or 1s2p 1P1 → 1s2 1S0)
3. column: not important here\\
4. column: y-z (2 ^3P_1 → 2 ^3S_1 or 1s2p 3P1 → 1s2s 3S1), i.e., they give upper level y minus upper level z
5. column: x-z (2 ^3P_2 → 2 ^3S_1 or 1s2p 3P2 → 1s2s 3S1)

and to obtain the triplet line energies thus

w: 2. column
y: 1. column
x: 5. column - 4. column + 1. column [i.e., (x-z)-(y-z)+y]
z: 1. column - 4. column [i.e., y-(y-z)]

I've written a small script that reads in the data copied from the Drake table and returns the value - please round yourself according to your needs and taking into account the data accuracy:

[[Triplett_line_energies|script]]

This script makes use of [[Ascii_version_of_the_first_35_lines_of_Table_3_from_Drake_19888|this ascii file]] that you will have to copy and name "drake_table3_cm.dat" - this is just an ascii version of the first 35 lines in Table 3 from the Drake paper.

Author --- [mailto:grinberg@space.mit.edu Victoria Grinberg] 2016-25-03

[[Category:Atomic Physics]]

Line triplet for He-like ions

2018-04-11T14:22:55Z

Kirsch: Added internal link

A helium-like ion is any nucleus with exactly two bound electrons.

=== F, I, R notation ===

F, I, R stand for forbidden, intercombination and resonance line.

* R is the strongest line (at least for certain plasma conditions).
* The intercombination lines have their name because they intercombine levels from a singlet state (1S) and a triplet state (3P). ''(In the really early days of spectroscopy, before it was known that singlets and triplets exists, it was actually thought that there are two types of He: parahelium and orthohelium. Now we know better.)''
* The forbidden line is called forbidden because it is not an electric dipole allowed transition. See [[What_are_"forbidden"_lines%3F | this note about forbidden lines]]

=== w, x, y, z notation ===

[http://adsabs.harvard.edu/abs/1972MNRAS.160...99G| Gabriel (1972)] used the 26 letters of the alphabet to cross-reference Li-like and He-like Kα transitions in his tables. Today, these letters are widely used in atomic and plasma physics to identify transitions in Li-like and He-like ions.
The figure below describes the w, x, y, z notation for the He-like ion triplet ([http://www.edpsciences.org/10.1051/0004-6361:20010959| Porquet et al. 2001]).

[[File:porquet_helike.png]]

=== Why are there two different transition (x and y) for the intercombination lines? ===

There are actually two lines, you just don't typically resolve them in elements seen in astrophysical plasmas (at the current resolution).

It's because of the [[atomic:rules | selection rules]]. You can excite an electron to any energy level, but for spontaneous decay you have to follow the selection rules.

[[Category:Atomic Physics]]

How to identify ions

2018-04-11T14:16:59Z

Kirsch: Migrated from old wiki

There are 3 distinct ways to name ions. All of them encode the element, i.e., the proton number ''Z'', and the number of electrons in the shell in one way or another. Which of these names is used, however, partly depends on preference, and partly on which information you would like to get across at first glance.

As an example, we'll use a carbon (C, ''Z''=6) ion with 2 (out of its 6) electrons left in its shell.

=== The Astrophysics Way ===

In astrophysics, just count your way through the iso-nuclear sequence (equal ''Z'') starting at the neutral, i.e., the neutral element is denoted by a Roman numeral I, one times ionized by a Roman II, and so forth.

So in our example:

'''C V'''

=== The Atomic Physics Way ===

Ions within the same iso-electronic sequence, i.e., same number of bound electrons but different nuclei (''Z''), usually show the same patterns of spectral lines. Iso-electronic sequences are named after the (neutral) element with Z equal to the number of electrons. Denoting the ion via its iso-electronic sequence, tells you how many electrons the ion still has.

Neutral helium (He, ''Z''=2) carries 2 electrons; therefore, in our example, to show that C with 2 electrons behaves very much like neutral He, you would say:

''' He-like C '''

As a special case, H-like ions are sometimes also referred to as 'hydrogenic ions'.

=== The Chemistry Way ===

Rather than counting the number of electrons remaining in the ion, you can instead communicate the charge of the ion, which is equivalent to the number of missing electrons:

''' C4+ '''

----

Obviously, all three naming schemes can be translated into each other easily. However, this conversion requires some basic knowledge (or a printed version) of the periodic table, especially the number of protons, ''Z'', for some of the more abundant elements.

[[Category:Atomic Physics]]

Line triplet for He-like ions

2018-04-11T14:13:19Z

Kirsch: Migrated from old wiki

A helium-like ion is any nucleus with exactly two bound electrons.

=== F, I, R notation ===

F, I, R stand for forbidden, intercombination and resonance line.

* R is the strongest line (at least for certain plasma conditions).
* The intercombination lines have their name because they intercombine levels from a singlet state (1S) and a triplet state (3P). ''(In the really early days of spectroscopy, before it was known that singlets and triplets exists, it was actually thought that there are two types of He: parahelium and orthohelium. Now we know better.)''
* The forbidden line is called forbidden because it is not an electric dipole allowed transition. See [[atomic:forbidden | this note about forbidden lines]]

=== w, x, y, z notation ===

[http://adsabs.harvard.edu/abs/1972MNRAS.160...99G| Gabriel (1972)] used the 26 letters of the alphabet to cross-reference Li-like and He-like Kα transitions in his tables. Today, these letters are widely used in atomic and plasma physics to identify transitions in Li-like and He-like ions.
The figure below describes the w, x, y, z notation for the He-like ion triplet ([http://www.edpsciences.org/10.1051/0004-6361:20010959| Porquet et al. 2001]).

[[File:porquet_helike.png]]

=== Why are there two different transition (x and y) for the intercombination lines? ===

There are actually two lines, you just don't typically resolve them in elements seen in astrophysical plasmas (at the current resolution).

It's because of the [[atomic:rules | selection rules]]. You can excite an electron to any energy level, but for spontaneous decay you have to follow the selection rules.

[[Category:Atomic Physics]]

What are "forbidden" lines?

2018-04-11T14:03:34Z

Kirsch: Migrated from old wiki

''' Astrophysicist interpretation: '''

{{cquote|The transition rate for forbidden lines is incredibly low. That means it is much more likely for an electron to transfer to a different state (via collisions or photo-excitation) than it is for spontaneous decay along the forbidden path. That's why we can see "forbidden" lines from the diffuse ISM; the densities are so low that the collision rate is smaller than the spontaneous decay rate (<latex>A_{ji}</latex>), which is not typical for laboratory conditions on Earth at the time these naming conventions took hold.}}

''' Atomic physicist: '''

{{cquote|Usually you'd call a line forbidden if it is not a electric dipole allowed transition. There are a number of other possibilities: magnetic dipole, electric quadrupole, magnetic quadrupole, electric octupole, magnetic ... you get the picture. All of these have smaller and smaller probabilities to actually happen. So all that 'forbidden' really means is that the transition really has smallish Einstein A, i.e., spontaneous decay rate.}}

----

=== "Strictly forbidden" lines ===

If you look at the table for the selection rules (e.g., [http://en.wikipedia.org/wiki/Selection_rules]), you will find some transitions, especially those with J = 0 -> 0, that are never allowed in any of the multipole things, i.e., they are truly forbidden and you will really never ever see them.

In astrophysics, these are often referred to as ''"strictly forbidden"''.

Examples for these truly forbidden transitions are the 1s2s 1S0 → 1s2 1S0 and 1s2p 3P0 → 1s2 1S0 transitions. You can cascade from higher levels into those, but they won't spontaneously decay into the ground state.

[[Category:Atomic Physics]]

Ascii version of the first 35 lines of Table 3 from Drake 19888

2018-04-11T13:57:23Z

Kirsch: Migrated from old wiki

<nowiki>
2 169086.83 171134.88 9231.858 9230.869 9230.791
3 494260.38 501807.65 18231.312 18226.107 18228.194
4 983368.87 997469.04 26864.636 26853.039 26867.916
5 1636937.96 1657995.05 35393.703 35377.399 35430.023
6 2455178.84 2483400.63 43898.958 43886.220 44021.942
7 3438278.56 3473794.30 52420.973 52429.204 52720.061
8 4586390.31 4629307.20 60979.645 61037.666 61588.977
9 5899703.39 5950124.44 69592.461 69742.414 70699.796
10 7378380.09 7436433.28 78265.904 78564.658 80121.595
11 9022687. 9088513. 87019.10 87539.08 89945.37
12 10832818. 10906612. 95853.40 96682.51 100252.85
13 12809088. 12891081. 104786.69 106027.61 111152.07
14 14951735. 15042237. 113819.77 115588.17 122743.06
15 17261119. 17360506. 122969.89 125391.65 135151.74
16 19737521. 19846285. 132237.68 135445.29 148496.89
17 22381344. 22500075. 141640.19 145768.00 162923.38
18 25192959. 25322387. 151185.71 156364.73 178577.07
19 28172675. 28313718. 160868.54 167221.35 195599.64
20 31320989. 31474717. 170711.69 178345.79 214171.71
21 34638371. 34806046. 180729.38 189731.77 234475.31
22 38125207. 38308336. 190918.03 201351.51 256684.94
23 41782013. 41982336. 201291.80 213190.33 281003.58
24 45609274. 45828791. 211855.64 225222.44 307635.71
25 49607558. 49848527. 222624.75 237429.71 336807.19
26 53777413. 54042384. 233603.92 249785.36 368744.59
27 58119468. 58411271. 244808.91 262272.34 403697.11
28 62634307. 62956085. 256240.03 274863.30 441909.98
29 67322654. 67677827. 267920.31 287549.55 483663.60
30 72185152. 72577481. 279847.13 300307.83 529224.53
31 77222612. 77656158. 292045.18 313136.50 578899.77
32 82435721. 82914884. 304511.37 326015.13 632981.03
33 87825330. 88354850. 317262.02 338943.03 691792.93
34 93392273. 93977223. 330308.99 351913.62 755669.35
35 99137441. 99783268. 343660.72 364926.78 824954.50
36 105061720. 105774218. 357330.35 377975.62 900012.11
</nowiki>

[[Category:Atomic Physics]]

Triplett line energies

2018-04-11T13:54:32Z

Kirsch: Migrated from old wiki

<nowiki>require("isisscripts");

%read in data from the drake 1998 table
variable dk = ascii_read_table("drake_table3_cm.dat",
[{"%d"},{"%F"},{"%F"},{"%F"},{"%F"},{"%F"}]);

%conversion factor from cm^-1 to keV
variable cf = 8065730;

%list of elements
variable elem = ["He","Li","Be","B","C","N","O","F","Ne","Na","Mg","Al",
"Si","P","S","Cl","Ar","K","Ca","Sc","Ti","V","Cr","Mn",
"Fe","Co","Ni","Cu","Zn","Ga","Ge","As","Se","Br","Kr"];

%define structure for the lines; line conversion from the values in
%Drake is according to what Natalie told me what the individual columns
%in the table represent
variable tri = struct{element = elem,
w = dk.col3/cf,
y = dk.col2/cf,
x = (dk.col6-dk.col5+dk.col2)/cf,
z = (dk.col2 - dk.col5)/cf};

%write fits fite and ascii file
fits_write_binary_table("tripletts.fits","DATA",tri);
print_struct("tripletts.dat",tri);

print("STACK:");
_print_stack;
exit;</nowiki>

[[Category:Atomic Physics]]

Triplett energies according to Drake 1988

2018-04-11T13:50:12Z

Kirsch: Migrated from old wiki

More exact triplett energies than those given in Alex Markowitz's list can be obtained from the Drake 1988 paper

http://adsabs.harvard.edu/abs/1988CaJPh..66..586D

(Note that the references, as always, matters. Other literature references may result in somewhat different lines. The joys of it ...)

In particular, the important part is Table 3. However, instead of direct line energies, it lists things in a somewhat more complex way and in 1/cm, at least for elements He to Kr, i.e., everything that will ever matter in your normal observed spectrum, namely (with thanks to Natalie):

1. column: y (2 ^3P_1 → 1 ^1S_0 or 1s2p 3P1 → 1s2 1S0)
2. column: w (2 ^1P_1 → 1 ^1S_0 or 1s2p 1P1 → 1s2 1S0)
3. column: not important here\\
4. column: y-z (2 ^3P_1 → 2 ^3S_1 or 1s2p 3P1 → 1s2s 3S1), i.e., they give upper level y minus upper level z
5. column: x-z (2 ^3P_2 → 2 ^3S_1 or 1s2p 3P2 → 1s2s 3S1)

and to obtain the triplet line energies thus

w: 2. column
y: 1. column
x: 5. column - 4. column + 1. column [i.e., (x-z)-(y-z)+y]
z: 1. column - 4. column [i.e., y-(y-z)]

I've written a small script that reads in the data copied from the Drake table and returns the value - please round yourself according to your needs and taking into account the data accuracy:

[[draketriplettscripts|script]]

This script makes use of [[draketriplettslist|this ascii file]] that you will have to copy and name "drake_table3_cm.dat" - this is just an ascii version of the first 35 lines in Table 3 from the Drake paper.

Author --- [mailto:grinberg@space.mit.edu Victoria Grinberg] 2016-25-03

[[Category:Atomic Physics]]

Atomic Databases: General idea and limitations

2018-04-11T13:37:39Z

Kirsch: Migrated

''informal rant from an email that I wrote. Needs some cleaning up. Don't cite!!!''

=== Idealistic principle: ===

Only well tested / benchmarked / reliable data goes into reference databases. At the same time, the database includes any data anyone could possibly ever need.

=== Problems / Limitations: ===
Databases would be kinda small and pretty much biased against certain lines that are weak or rare. But the better our instruments (satellites) get, the more (and reliable and accurate) reference data we'll need. Also, it is better to know that there is a line that falls roughly into the right energy band, even if it's somewhat off, than to be completely clueless about what the observed feature could be.

There is only so much you can do about the accuracy part. Therefore, it would be nice if the atomic data came with uncertainties and fit algorithms could handle uncertainties in the model as well as the data. Randall and Adam have been trying to sell this point, but people do not yet think this is a thing (i.e., that proposal got no funding. At least twice, I believe.). These people will come whining soon (around the year 2030 the latest^^).

=== Uncertainties for reference data ===

Currently, only a rather small fraction of the data in AtomDB comes with uncertainties (exhibit A: atomdb3err.png, from Smith & Brickhouse 2014); some of them relatively bad. Laboratory data have the advantage that experimentalist usually have a pretty good grasp of what the limitations of their instruments (and analysis) are. So usually they come out with reasonable errorbars.

Theorists have 2 problems:
# they (ok, not all of them) believe their calculations are accurate ala "dude, it's a calculation, of course there are no uncertainties!" - except, outside of H-like, the equations cannot be solved analytically, i.e., perturbation theories, i.e., approximations. Plus there are still some open questions as to what is the correct description of interactions in each ion (things like relativistic effects, distorted waves, the amount of configuration interactions, etc).

# it's much harder to get an estimate for uncertainties on your theories. i guess, one way to do it, would be to play with certain parameters, run the code a bunch of times, see how the results scatter. I don't think anybody really does that. Also, you'd still not really know how reliable those uncertainties are. The other options are to compare the calculation to experimental data (if they exist; plus they're also only so accurate) or to compare to other theories. I don;t quite see the point of comparing to other theories: why do we need 20 different codes that produce the exact same result?

The comparison between theory and experiment are important, though, because we need to understand the theory better. For one, because physics. But also because we cannot systematically measure everything at the lab. There is neither time nor money. Also, some things blend so badly that even the best instruments will never be able to split the lines. Therefore, we do need the codes to fill up the databases. We just need to make sure first that we can trust them -- at least to a certain degree of accuracy.

To some extend it's also an interpretation question: if you can measure a certain line in the lab really accurately, you can compare different theories and see if, for example, QED plays an important role for that line or whether it has no contribution.

To be fair, experimentalists have problems, too:
* in experiments, things can go wrong, too. Especially, what you would call an "absolute" measurement is really hard to do. A lot of the times, especially for wavelengths measurements, relative measurements are by far more common, i.e., you measure a calibration spectrum containing lines whose wavelengths are well known, use that to set up your scale, then use that scale to derive the wavelengths of the "unknown" lines. So at best the accuracy of the newly measured lines is as good as the uncertainty of the reference lines, usually a bit lower. You can see how this is going to decay... . Plus you cannot easily swap the underlying reference wavelengths for other wavelengths, because usually the scale is not linear.

=== The hard life of data providers ===
Collections like atomic databases are very convenient for a lot of people, especially the ones not well versed in atomic physics, since everything can be found in a single place and has undergone -- to some extend at least -- quality control. However, these databases pose a major problem for '''data providers''' -- this includes experimentalists as well as theorists: '''they do not get the citations they need'''.

Everyone is aware that a high number of citations is key to survival in science; citations are what makes papers ''high impact'' and help to secure funding for future projects. Papers providing reference data often are merely cited by the database that incorporates their results, but hardly ever by people actually using the provided data. This way the database gets many citations. However, citations do not recursively trickle down to the original source.
This makes it really hard for the data providers to keep a track record of how widely used their work is. By extension this can lead to the data providers not longer being able to provide the data that is needed by the community.

Less political, but science-wise equally important: citing improperly also makes it harder to compare, e.g., Doppler shifts derived in different papers, since differences in the Doppler shift do not only depend on the observation/analysis, but also on the value of the reference wavelength. Similarly, for relative intensities, etc. And sometimes even the database is not cited.

Please be aware of this situation and try to cite atomic reference papers properly -- especially if you pick specific sets of reference lines out of the database (in contrast to using a fit functions that relies on the whole database).
In practice this means: refer to the atomic database that you used to find the reference data (including the version number), but then also go the extra step and '''look up and cite''' the original paper where the data came from. This information is included in the database for everyone to find.

[[Category:Atomic Physics]]

Common lines in the X-rays: K α, He α, Ly α

2018-04-11T13:29:40Z

Kirsch: Fixed footnote

=== Principle quantum number ===
In a very simple model (the Bohr model), an atom is thought of as a solar system like setup: the nucleus, consisting of protons and neutrons, i.e. the bulk of the mass, is 'orbited' by the electrons on discrete energy levels (orbitals). But unlike the solar system in an atom the attraction is provided by electromagnetic forces rather than gravity. For the orbitals the potential energy increases with distance to the nucleus. The location of an electron in one of these energy levels is denoted by the principle quantum number ''n'' where ''n''=1 corresponds to the innermost orbital.

Often these energy levels are denoted with letters: the energy levels K,L,M,... correpsond to the principal quantum numbers ''n''=1,2,3,... .
Each orbital can hold ''2n2'' electrons.

The state of an atom or ion with the lowest possible energy, is called the ''ground'' state. In the ground state, all electrons are located in orbitals as close to the nucleus as possible. However, electrons can jump between different orbitals. In order to excite an electron to higher levels, it needs to absorb additional energy, e.g., from photons or through collisions. De-excitation of an electron into a lower level can also happen spontaneously by emitting energy in form of a photon.

Note that the Bohr model is a first-order approximation and can only explain the principle quantum number. For a more accurate description of orbitals, quantum mechanics is
essential.

=== Rydberg series in Hydrogen ===
Early on it was discovered that the emission spectrum of atomic hydrogen, the simplest of all atoms, forms a distinct set of spectral series. These series are called the Rydberg series, after the Swedish physicist who discovered a description for these series in the late 1880s. He found that within each series the lines have the same lower level and that the wavelengths of the emission lines can be reproduced by the Rydberg formula

1/λ = ''R'' (1/n'2 - 1/n2)

where n' is the lower energy level, n the upper energy level, and ''R'' the Rydberg constant.
The first handful of series are named after famous physcists:

{| class="wikitable" style="text-align: left;"
|-
! style="text-align: left;width:5em;" |n'
! style="text-align: left;width:15em;" |series
|-
|1 (K)
|Lyman series
|-
|2 (L)
|Balmer series
|-
|3 (M)
|Paschen series
|-
|4 (N)
|Brackett series
|-
|5 (O)
|Pfund series
|-
|6 (P)
|Humphreys series
|-
|}

Spectral lines within a series are designated with Greek letters depending on the upper level, starting with α for n=n'+1, β for n=n'+2, etc. For example, a transition from n=2 to n'=1 would be called Lyman α, or Ly α for short.

=== Generalization of the Rydberg series ===

In case of the hydrogen atom, the nucleus contains only a proton. There are other systems, H-like ions, where also only 1 electron orbits around an albeit heavier nucleus that can contain multiple protons and neutrons depending on the element. These hydrogenic ions display the same series of spectral lines as the hydrogen atom, only at higher energies. Their wavelengths are described by the Rydberg formula modified by a factor of ''Z''2, where ''Z'' is the atomic number, i.e., the proton number of the element.
Starting with about H-like B (Ly α ~250 eV) some of these transitions (especially the Lyman series) fall into the X-ray regime.

It turns out that the Rydberg series can be found in even more generalized ions. Adding a second electron to the ion still results in a pattern of spectral lines very similar to the pattern known from the hydrogenic ions.
But the negative charge of the second electron does screen the positive charge of the nucleus that the first electron "feels" to some extend, effectively lowering ''Z''2. The spectral lines of the He-like system are therefore shifted to somewhat lower energies than the lines in the H-like ion with the same atomic number.

The same is true for basically any number of electrons; if the electron distribution in the orbitals is such that the transitions can occur, the familiar pattern of the Rydberg series can be observed.
However, due to the larger number of electrons, the ions become too complex and the Rydberg formula can no longer reproduce the wavelengths of the corresponding transitions.

==== K transitions ====

Transitions into the K-shell are the equivalent of the Lyman series for multi-electron ions.
This type of transition is the most common transitions in the X-rays. They're easily produced in He-like and H-like ions, but also possible in ions with lower ionization stages. He- and H-like ions are often the dominant (along with bare ions, but bare ions have no electrons to jump between levels and therefore do not produce spectral lines) ionization stage in energetic or hot environments like the vicinity of black holes, since for mid-Z elements the energy needed to produce He- and H-like ions (ionization potential) is fairly low (~4.12 keV to make H-like Ar).

==== others ====

Of course, also the other series besides the Lyman series have their equivalents in multi-electron systems. But since the energy difference between neighboring orbitals decreases with increasing ''n''', already the L-shell transitions (Balmer series equivalent) for the lighter elements move into the UV region. For example, Fe L lines (for various ionization stages of Fe) largely fall below 1 keV, with a limit of about 1.3 keV.

To see M-shell transitions in the X-rays, high-Z elements (e.g., Eu, W) are required. The relative abundance of these elements is so low that they are not typically observed in astrophysics.

=== So what's the difference between K α, He α, and Ly α? ===

K α is a general term denoting the transition of an electron between the n'=1 and n=2 energy levels. Such a transition can happen in any ion, provided there is an initial open space (hole) in the final orbital (in n'=1 for emission, n=2 for absorption). Configurations with such an inner-shell hole can also occur in ions that have electrons in the n>=3 orbitals. Therefore, "Fe K α" (for example) could be a spectral line originating from a n=1-2 transition in '''any''' Fe ion.

To be more specific, for such a transition in helium-like Fe, i.e., Fe with 2 electrons, one could say "He-like Fe K α" - or "Fe He α" for short.

Because of the history of the Rydberg series, a K α transition in a hydrogenic ion is still called Ly α. In case of the Fe example, this would be "Fe Ly α" for H-like Fe.

=== Fine structure ===

The Bohr model and the Rydberg formula only account for the gross structure of the spectra, which only depends on the principle quantum number ''n''. In reality, a number of other effects (kinetic energy relativistic correction, spin-orbit coupling, Darwin term) separate this gross structure into finer levels.
This is referred to as fine structure splitting. It lifts the degeneracy of the levels in //n// and splits the sub-shells into separate energy levels that now also depend on the angular momentum (azimuthal) and total angular momentum quantum numbers ''l'' and ''j''.
Every orbital has ''l''=0,1,...,''n''-1 sub-shells, which in turn split into one to two levels with total angular momenta ''j''=''l''+-1/2. The values of ''l'' are often written in form of letters where ''l''=s,p,d,f,g,... correspond to ''l''=0,1,2,... .
With this fine structure splitting, transitions from ''n''=2 to ''n'''=1 have slightly different energies. For example, the transition 2p1/2->1s1/2 has a slightly lower energy than the transition 2p3/2->1s1/2. Using spectrometers with sufficient spectral resolution, Ly α is seen as two distinct lines Ly α2 and Ly α1.
While these individual lines are still a, e.g., K α type transition, they often have individual "names" to identify them. See, for example, the [[atomic:he-triplet|the He-like system]].

[[Category:Atomic Physics]]

Common lines in the X-rays: K α, He α, Ly α

2018-04-11T13:22:52Z

Kirsch: Migrated from old wiki.

=== Principle quantum number ===
In a very simple model (the Bohr model), an atom is thought of as a solar system like setup: the nucleus, consisting of protons and neutrons, i.e. the bulk of the mass, is 'orbited' by the electrons on discrete energy levels (orbitals). But unlike the solar system in an atom the attraction is provided by electromagnetic forces rather than gravity. For the orbitals the potential energy increases with distance to the nucleus. The location of an electron in one of these energy levels is denoted by the principle quantum number ''n'' where ''n''=1 corresponds to the innermost orbital.

Often these energy levels are denoted with letters: the energy levels K,L,M,... correpsond to the principal quantum numbers ''n''=1,2,3,... .
Each orbital can hold ''2n2'' electrons.

The state of an atom or ion with the lowest possible energy, is called the ''ground'' state. In the ground state, all electrons are located in orbitals as close to the nucleus as possible. However, electrons can jump between different orbitals. In order to excite an electron to higher levels, it needs to absorb additional energy, e.g., from photons or through collisions. De-excitation of an electron into a lower level can also happen spontaneously by emitting energy in form of a photon.

Note that the Bohr model is a first-order approximation and can only explain the principle quantum number. For a more accurate description of orbitals, quantum mechanics is
essential.

=== Rydberg series in Hydrogen ===
Early on it was discovered that the emission spectrum of atomic hydrogen, the simplest of all atoms, forms a distinct set of spectral series. These series are called the Rydberg series, after the Swedish physicist who discovered a description for these series in the late 1880s. He found that within each series the lines have the same lower level and that the wavelengths of the emission lines can be reproduced by the Rydberg formula

1/λ = ''R'' (1/n'2 - 1/n2)

where n' is the lower energy level, n the upper energy level, and ''R'' the Rydberg constant.
The first handful of series are named after famous physcists:

{| class="wikitable" style="text-align: left;"
|-
! style="text-align: left;width:5em;" |n'
! style="text-align: left;width:15em;" |series
|-
|1 (K)
|Lyman series
|-
|2 (L)
|Balmer series
|-
|3 (M)
|Paschen series
|-
|4 (N)
|Brackett series
|-
|5 (O)
|Pfund series
|-
|6 (P)
|Humphreys series
|-
|}

Spectral lines within a series are designated with Greek letters depending on the upper level, starting with α for n=n'+1, β for n=n'+2, etc. For example, a transition from n=2 to n'=1 would be called Lyman α, or Ly α for short.

=== Generalization of the Rydberg series ===

In case of the hydrogen atom, the nucleus contains only a proton. There are other systems, H-like ions, where also only 1 electron orbits around an albeit heavier nucleus that can contain multiple protons and neutrons depending on the element. These hydrogenic ions display the same series of spectral lines as the hydrogen atom, only at higher energies. Their wavelengths are described by the Rydberg formula modified by a factor of ''Z''2, where ''Z'' is the atomic number, i.e., the proton number of the element.
Starting with about H-like B (Ly α ~250 eV) some of these transitions (especially the Lyman series) fall into the X-ray regime.

It turns out that the Rydberg series can be found in even more generalized ions. Adding a second electron to the ion still results in a pattern of spectral lines very similar to the pattern known from the hydrogenic ions.
But the negative charge of the second electron does screen the positive charge of the nucleus that the first electron "feels" to some extend, effectively lowering ''Z''2. The spectral lines of the He-like system are therefore shifted to somewhat lower energies than the lines in the H-like ion with the same atomic number.

The same is true for basically any number of electrons; if the electron distribution in the orbitals is such that the transitions can occur, the familiar pattern of the Rydberg series can be observed.
However, due to the larger number of electrons, the ions become too complex and the Rydberg formula can no longer reproduce the wavelengths of the corresponding transitions.

==== K transitions ====

Transitions into the K-shell are the equivalent of the Lyman series for multi-electron ions.
This type of transition is the most common transitions in the X-rays. They're easily produced in He-like and H-like ions, but also possible in ions with lower ionization stages. He- and H-like ions are often the dominant((along with bare ions, but bare ions have no electrons to jump between levels and therefore do not produce spectral lines)) ionization stage in energetic or hot environments like the vicinity of black holes, since for mid-Z elements the energy needed to produce He- and H-like ions (ionization potential) is fairly low (~4.12 keV to make H-like Ar).

==== others ====

Of course, also the other series besides the Lyman series have their equivalents in multi-electron systems. But since the energy difference between neighboring orbitals decreases with increasing ''n''', already the L-shell transitions (Balmer series equivalent) for the lighter elements move into the UV region. For example, Fe L lines (for various ionization stages of Fe) largely fall below 1 keV, with a limit of about 1.3 keV.

To see M-shell transitions in the X-rays, high-Z elements (e.g., Eu, W) are required. The relative abundance of these elements is so low that they are not typically observed in astrophysics.

=== So what's the difference between K α, He α, and Ly α? ===

K α is a general term denoting the transition of an electron between the n'=1 and n=2 energy levels. Such a transition can happen in any ion, provided there is an initial open space (hole) in the final orbital (in n'=1 for emission, n=2 for absorption). Configurations with such an inner-shell hole can also occur in ions that have electrons in the n>=3 orbitals. Therefore, "Fe K α" (for example) could be a spectral line originating from a n=1-2 transition in '''any''' Fe ion.

To be more specific, for such a transition in helium-like Fe, i.e., Fe with 2 electrons, one could say "He-like Fe K α" - or "Fe He α" for short.

Because of the history of the Rydberg series, a K α transition in a hydrogenic ion is still called Ly α. In case of the Fe example, this would be "Fe Ly α" for H-like Fe.

=== Fine structure ===

The Bohr model and the Rydberg formula only account for the gross structure of the spectra, which only depends on the principle quantum number ''n''. In reality, a number of other effects (kinetic energy relativistic correction, spin-orbit coupling, Darwin term) separate this gross structure into finer levels.
This is referred to as fine structure splitting. It lifts the degeneracy of the levels in //n// and splits the sub-shells into separate energy levels that now also depend on the angular momentum (azimuthal) and total angular momentum quantum numbers ''l'' and ''j''.
Every orbital has ''l''=0,1,...,''n''-1 sub-shells, which in turn split into one to two levels with total angular momenta ''j''=''l''+-1/2. The values of ''l'' are often written in form of letters where ''l''=s,p,d,f,g,... correspond to ''l''=0,1,2,... .
With this fine structure splitting, transitions from ''n''=2 to ''n'''=1 have slightly different energies. For example, the transition 2p1/2->1s1/2 has a slightly lower energy than the transition 2p3/2->1s1/2. Using spectrometers with sufficient spectral resolution, Ly α is seen as two distinct lines Ly α2 and Ly α1.
While these individual lines are still a, e.g., K α type transition, they often have individual "names" to identify them. See, for example, the [[atomic:he-triplet|the He-like system]].

[[Category:Atomic Physics]]

AtomdDB: a guide

2018-04-11T13:04:42Z

Kirsch: Migrated from old wiki.

''informal rant from an email that I wrote. Needs some cleaning up. Don't cite!!!''

''link to AtomDB''

With AtomDB, you have to be a little careful. It does list two wavelengths. One is called "lab/observed" (use this one whenever possible), the other one "theory". This is somewhat misleading. The real distinction is:

* '''lab/observed''': wavelengths that are widely accepted as being a good reference. This can be either experimental or theoretical. For example, in the case of He-like Ka lines, (for the more common elements) these wavelengths are from Drake 1988, which, as even the title will tell you, are theoretical calculations. They're good (we here use them as calibration references), but they're calculated. In atomDB, the lab/observed wavelengths tend to come with uncertainties.

* '''theory''': mass calculations, and not necessarily good ones at that. They're easily recognizable by their references, such as "Afoster Autos 2010" (= Adam ran autostructure in 2010), "* Afoster FAC *" (= Adam used FAC [he doesn't know any more about FAC than I do], these are more recent to extend Atomdb (3) to include innershell transitions in lower charge states), "Whiteford ICFT" (I don't know the guy, but wavelengths labeled with that are like really really really ... really bad).

==== Why the distinction? ====

The reason for this two-class system is that for a lot of the "good" wavelengths that's what you get - the wavelength. Especially experiments have a hard time to measure the level energies (note: line = transition between two levels). However, for all these sophisticated plasma models you need way more information, including level energies (a line is the transition between two levels. You can't really measure levels in the lab - or at least I don't know how), radiative rates (Einstein A), but also (temperature dependent) collision strengths, recombination rates, etc. Not only do you need all that information for the strong distinct lines you, Vici, for example, see in your Vela X-1 spectra. To get relative line strengths, charge balance, etc, right in your models, you also need to include all (or at least most) those weak transitions nobody would otherwise care about much. To make calculations easier and databases smaller, you can shove some of the really weak stuff that nobody will ever resolve into something that's called a pseudo-continuum (yes, if you add everything, there is enough weak stuff to create a continuum).

So, since AtomDB is not only supposed to be a look-up table but also provide plasma modelling, all the gaps between the good references are filled up with massive in-house calculations, mostly run by Adam. He is not a theorist. He does some checks, but cannot possibly check everything in detail like a theorist writing a paper about a specific line list would (should?) do. To some extend, these calculations are fine (e.g., the "Afoster Autos 2010" for you Si Lya is not bad), but there are some for which I really don't understand how they ever made it into the database...).
Worst case example: Whiteford ICFT. These seem to affect mostly the He-like systems. For example, Si XIII He alpha (r/resonance or w, upper level ID = 7). The lines is supposed to be at 1865 eV (lab/observed), Whiteford ICFT lists it at 1867 eV (theory). Even worse, for He-like Fe XXV w (same line) the difference is ~10eV. That is so bad that I had a really hard time making Greg believe me that that's actually what the database says - until he finally looked it up himself.

==== Best practice ====

Long story(ies) short: '''it is a good policy to always default to the lab/observed wavelengths'''. As far as I know, even the xspec models (are supposed to) use theory only if lab/observed is NULL.

At the very least, you should never take the level energies out of the level list. Logically, you'd think, if your transition goes into the ground state (level energy = 0), the transition energy should be equal to the energy of the upper level. Plus it's more convenient, because you don't have to go the extra step (that page loads slowly) and it's already in energy, i.e., no extra conversion from wavelength. Problem is, the level energies come from these massive data runs, and especially in the case of the "Whiteford ICFT" reference, they are pretty off.

=== What can happen if theories are mixed (within an ion) ===
Interesting things can happen if different calculations for the same ion are combined, as shown in exhibit B (reqres.pdf) [Lia, you've seen this before]. Originally, I made this plot, because I wanted to see what resolution is required (the purple shades are Astro-H) to be able to resolve lines of the He-triplet. The energy differences between two transitions for each He-like ion is color-coded (see legend) for whether one, both, or none of the two transitions was available as an "observed" line. As you can see, in the He-like case the observed and the theory pretty much follow the same trend, but are shifted with respect to each other. If one line was observed, but the other only theory, the difference between the transitions is a significant outlier to the overall trend. You can also see, that the trends in H-like (Lya1-Lya2) seem to agree better between theory and observed, which might be an indication that the theory is not so bad.

[[Category:Atomic Physics]]

Alex Markowitz' Line List

2018-04-11T12:52:45Z

Kirsch: Created page with "Alex Markowitz has compiled an [VG: extremely useful in my opinion] list of lines that can be encountered in AGN here: http://www.sternwarte.uni-erlangen.de/~markowitz/alllin..."

Alex Markowitz has compiled an [VG: extremely useful in my opinion] list of lines that can be encountered in AGN here:

http://www.sternwarte.uni-erlangen.de/~markowitz/alllines.html

Some remarks from Alex: the line list is poorly documented. And "There are a lot of lines, and for most of what we AGN people do, the neutral, He-like and H-like transitions are the usual suspects."

-- please use the list only as reference and check (back with Alex and on your own) the exact line energies.

Some of Natalie's remarks: The transition energies you list have "only" 1eV accuracy - this will be a problem if you are working with grating or calorimeter resolution and want exact line shift. It is good enough for CCD resolution spectra, though. The Fe XXV w absorption/emission should not be two lines -- this is likely due to different literature references.

[[Category:Atomic Physics]]