`RELXILL`v0.2e

`RELXILL` is a brand new model, joining forces of
the `XILLVER` reflection code (link;
Garcia et al., 2010, 2011, 2013) and the `RELLINE` code
(Dauser et al., 2010, 2013). The striking new feature is that for
each point on the disk the proper xillver-reflection spectrum is
chosen for each relativistically calculated emission angle. The
implications of this improvement and more details regarding the
model are provided in Garcia & Dauser et al., 2014, ApJ, 782, 76
(2014) and Dauser & Garcia et al. (subm. to MNRAS). See also this
pdf for a short information on all
models and their parameters.

v0.2e: several bug fixes were applied (e.g., problems occured with the reflection fraction when combining relxill and xillver, the reshift parameter in xillver, and for certain combinations of the fixReflFrac switch)

v0.2d: updated to code to use the new 1 MeV Ecut table

v0.2c: added non-relativistic xillver model

v0.2c: added relxilllp_alpha, using the alpha disk density (see Shakura & Sunyaev, 1973)

v0.2a: Major Update: added models relxill_ion and relxilllp_ion, which allow to take an ionization gradient in the disk into account (see below on information on how these models work).

v0.1e: bug fixed: if fixRelRefl=1, the model was not always working properly

v0.1d: fixed minor bug when displaying the reflection fraction

v0.1c: added the possibility to
fix and display the reflection fraction to the one predicted from
the lamp post setup (applies only to `relxilllp`)

v0.1b: Major change to the
structure of `relxill`.

- The table now includes a cutoff energy (Ecut). However, unfortunately this requires a larger table to be downloaded.
- The model is now evaluated on a fixed energy grid, yielding a huge improvement in speed for complicated datasets.
- We added the parameter "reflection fraction", with equal definition like in the pexrav model. Hence, for a positive value of this parameter, the primary power law and the reflection spectrum are returned (see below for more information)

### General Information

By installing the
new `RELXILL` model, all previous implementations of the
`relline`-like and `relconv`-like models are
automatically installed, too. These models are completely
identical to the ones from the `RELLINE` installation (hence,
no additional installation of relline is necessary to get the
previous functionalities).

### Usage and Parameters

The`RELXILL`model now includes by default the irradiating power law source. It's strength can be set by the parameter

`refl_frac`. Note, however, that for a negative value of

`refl_frac`, only the reflection compontent will be returned (equal to the pexrav model definition). All information can also be found in this pdf: download

norm: | defined as the normalization of xillver divided by
the ionization parameter |

refl_frac: | reflection fraction, with the same definition
as pexrav; calculated between 20 and 40 keV |

Ecut: | cutoff energy in keV (the same for the power law and the reflection spectrum) |

angleon: | 0: angle averaging (see below for more information) |

1: take angles properly into account | |

fixReflFrac: | 0: free reflection fraction (determined by
the refl_frac parameter) |

1: fix reflection fraction to the lamp post value (i.e.,
the parameter refl_frac has NO meaning in this case) | |

2: free, (same as 0:), but now the reflection fraction is displayed on the screen |

The meaning of the parameters is the same as
for the separate models. The only exception is the additional
parameter **angleon**. If set to **0**, the relxill model acts
like a simple `RELCONV x XILLVER`, hence using only the angle
averaged reflection spectra and then applying the relativistic smear.
However, if set to **1**, it acts as described above: For each
point on the disk the proper xillver-reflection spectrum is chosen for
each relativistically calculated emission angle. Note that due to the
relativistic effects the emission angle is generally not equal to the
inclination angle and therefore this more complicated approach is
necessary. Moreover, as the angular effects are properly treated, no
"guess" regarding a limb brightening or darkening law is needed
anymore.
Hence, unless you really know what you
are doing: Leave **angleon=1**. It is definitely the exacter model
(no matter what your chi2 value is telling you)!

### Download

To install, please download the following files:

last changes | in version | |

relxill_code.tgz | 2014-10-09 | v0.2e |

tables.fits.tgz (warning: 708MB) | 2014-07-11 | v0.2d |

The installation is similar to the relline model (look here). Note that you can use the environment variable RELLINE_TABLES to point to the complete set of provided tables, including the xillver table.

### A Comparison between `RELXILL` and the angle averaged approach

`RELXILL`(standard parameters: logxi=2, gamma=2, index=3, spin=0.99). Middle: Ratio between relxill and the conventional relconv*xillver. Right: Relativ distribution of flux for different emission angles. Note the angle averaged approach, which is commonly used, assumes a flat distribution here.

The code here is still in *BETA-test!* Please contact
me if
you find bugs or encounter problems with the model.