Cepheus X-4
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Also known as: GS 2138 + 56, V* V490 Cep
Simbad
Monitoring Data: CGRO/BATSE [Swift]MAXI Fermi/GBM pulsed flux RXTE/ASM
Coordinates
| Ra | 21h 39m 30.6s | Dec | +56º 59' 12.9 |
| l | 99.01 | b | +3.31 |
([1])
Binary System
Known to be a Be high mass X-ray binary system.
Distance
Determined to be 3.8 ± 0.6 kpc ([2])
Orbit
Period: Between 20-23 days[3][4]
Companion
Spectral Type: B1 V-B2 V
Magnitude: mv = 14.2, Mv = -(2.5-3.8)
([2])
Available Data
- RXTE: Mostly individual observations in 1997, 2002 and 2004 for ≤3 ksec. Up to 50 ksec in 1997 and 2002.
- RXTE: As part of the All-Sky Monitor Long Term Observed Sources. First observed in 1996.
- Ginga: Various observations in April 1988.
- INTEGRAL: Many pointed observations as part of CORE and GPS.
- Suzaku: None as of yet.
Flux
Luminosity:
- Quiescent: Lx(0.1-100keV) = (3.3-6.2) 1033 erg.s-1 ([2])
- Outburst: Fermi/GBM detected the 2009 outburst where Lx(12-25 keV) = 4.8380 1035 erg.s-1 was measured. ([5])
Cyclotron Resonance: Detected at 30.7 keV. ([6]) ([4]). Asymmetric shape and luminosity dependence found by [7].
Spectrum:
Figure taken from [4]
Pulse Profile
Period: 66.30 s ([4])
Pulse profiles in the 2-5keV for various observations. Luminosity decreases from top to bottom.
References
- ↑ Roche, P., Green, L., Hoenig, M., 1997, IAU Circ., 6698 (NASA ADS)
- ↑ 2.0 2.1 2.2 Bonnet-Bidaud, J.M. & Mouchet, M., A&A, 332, L9 (NASA ADS)
- ↑ Koyama, K., Kawada, M., Tawara, Y., et al., 1991, ApJ, 366, L19 (NASA ADS)
- ↑ 4.0 4.1 4.2 4.3 McBride, V.A., Wilms, J., Coe, M.J., et al., 2007, A&A 470, 1065 (NASA ADS)
- ↑ Becklen, E., Finger, M.H., 2009, The Astronomer's Telegram, 1972 (NASA ADS)
- ↑ Mihara, T., Makishima, K., Kamijo, S. et al., 1991, ApJ, 379, L61 (NASA ADS)
- ↑ Fürst F., Pottschmidt K., Miyasaka H, et al., 2015, ArXiv e-prints, 1505.02788 (NASA ADS)