KS 1947+300
Also known as GRO J1948+32 Simbad
Monitoring Data: Swift/BAT MAXI RXTE/ASM
Coordinates
RA 19h 49m 35.49s , DEC +30° 12' 31.8"
RA 19.82653 , DEC +30.20911
l 66.0990 , b +02.0836
Binary System
Distance: 10 kpc (assuming standard luminosity, [1])
Orbit
| Parameter | Value | Unit | Reference |
|---|---|---|---|
| Porb | 440.415(7) | days | [2] |
| Tπ/2 | 51985.31(7) | MJD | [2] |
| a sin i | 137.4(1.2) | lt-sec | [2] |
| e | 0.034(7) | [2] | |
| ω | 33(3) | degrees | [2] |
Optical companion
Name: not reported in [1]
B0Ve star
| Parameter | Value | Unit | Reference |
|---|---|---|---|
| U | 14.76(8) | mag | [1] |
| B | 15.06(5) | mag | [1] |
| V | 14.16(3) | mag | [1] |
| R | 13.50(2) | mag | [1] |
| I | 12.77(4) | mag | [1] |
Description
The binary system was discovered in 1989 by Mir-Kvant/TTM and independently by BATSE in 1994. It is located in the constellation Cygnus and showed a strong outburst in 2000/2001. A few smaller outbursts followed until 2004. The source was in quiescence from then on until 2013, when it underwent an outbrust again, followed by moderate X-ray and optical activity. The 2000/2001 outburst was (among others) monitored by RXTE and BeppoSAX, the 2013 outburst by NuSTAR, Swift and Suzaku.
Spectrum
The spectrum of KS 1947+300 is well described by an absorbed cut-off power law with an additional black body component and a fluorescent iron line ([3], [4]) or a thermal Comptonization model with an additional black body ([2], [5]). During the 2013 outburst, a cyclotron line at 12.2 keV was discovered in NuSTAR data ([4])
Pulse period & profiles
The pulse period is ~18.8 s ([2]). The pulse profiles show a characteristic energy-dependence with a single broad peak at low energies which evolves to a narrow, secondary peak and a broad main peak ([5]). This evolution is rarely seen in X-ray pulsars. In most cases, the pulse profile is more complex at low energies and evolves to a sinusoidal shape at higher energies. The pulse profile is similar in shape to the one observed in IGR J16393-4643 ([6]).
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Negueruela I., Israel G., Marco A., et al., 2003, A&A, 397, 739 (NASA ADS)
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Galloway D., Morgan E., Levine A., 2004, ApJ 613, 1164 (NASA ADS)
- ↑ Tsygankov S., Lutovinov A., 2005, Ast. Let. 31, 88 (NASA ADS)
- ↑ 4.0 4.1 Fürst F., Pottschmidt K., Wilms J., et al., 2014, ApJ 784, L40 (NASA ADS)
- ↑ 5.0 5.1 Naik S., Callanan P., Paul B., et al., 2006, ApJ, 647, 1293 (NASA ADS)
- ↑ Islam N., Maitra C., Pradhan P., et al., 2015, MNRAS, 446, 4148 (NASA ADS)