Hostname: page-component-77c89778f8-gvh9x Total loading time: 0 Render date: 2024-07-20T22:47:57.806Z Has data issue: false hasContentIssue false
  • English
  • Français

Comptel Observations of X-Ray Binaries

Published online by Cambridge University Press:  12 April 2016

A. F. Iyudin
A. F. Iyudin*
Affiliation:
MPI für extraterrestrische Physik, Garching, FRG

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The COMPTEL experiment on the Compton Gamma-Ray Observatory measures γ–radiation in the energy range from 0.75 to 30 MeV [10]. X-ray binaries form one category of potential γ-ray sources. Up to now only two X-ray binaries, Cyg X-l and Nova Per, have been seen by COMPTEL.

Cyg X-l. Preliminary results were reported by [6] and indicate that (i) there was no evidence for any hardening of the spectrum near lMeV, (ii) the plasma temperature suggested by a Wien spectral model was much higher than that implied by hard X-ray observations. This latter conclusion seems to require a revision in the standard spectral model for Cyg X-l.

The α–ray flux from Cyg X-l is constant up to several MeV. The time history of the flux in the 0.75… 2.0 MeV energy range shows that there are no significant variations near 1 MeV. The average photon spectrum derived from all observations up to 1994 July shows evidence for significant emission extending well above 2 MeV, with a data point in the 2…5 MeV range at 4.3 σ significance. However, the observed flux near 1 MeV is significantly below that reported by HEAO-3 and several other balloon observations [6]. The COMPTEL spectral data show a broad line-like feature around ~ 4 MeV with the best fit of a single power law plus Gaussian. If we assume that the Gaussian represents a single broadened nuclear line of 12C*, then the width of 1.38 MeV demands a temperature of ~ 2 1012 K [7].

Type
Space Observations
Information
International Astronomical Union Colloquium , Volume 158: Cataclysmic Variables and Related Objects , 1996 , pp. 277 - 278
Copyright
Copyright © Kluwer 1996

References

1. Callanan, P.J., Garcia, M.R., McClintock, J.E., et al., 1995, Ap. J., 441, 786 CrossRefGoogle Scholar
2. Cameron, R.A., et al., 1992, IAUC 5587 Google Scholar
3. Chevalier, C., Ilovaisky, S.A., 1994, preprint No. 83, Observatoire de Haute-ProvenceGoogle Scholar
4. van Dijk, R., et al., 1994, in AIP 304 Conf. Proceed., “The Second Compton Symposium”, eds. Fichtel, C.E., Gehreis, N., Norris, J.P., (New York: AIP), p 197 Google Scholar
5. van Dijk, R., Bennett, K., Collmar, W., et al., 1995, A&A, 296, L33 Google Scholar
6. McConnell, M.L., Forrest, D., Ryan, J., et al., 1994, Ap. J., 424, 933 CrossRefGoogle Scholar
7. McConnell, M.L., et al., 1995, presented at the Third Compton Symposium, MünchenGoogle Scholar
8. Paciesas, W.C., et al., 1993, in AIP 304 Conf. Proceed., “The Second Compton Symposium”, eds. Fichtel, C.E., Gehrels, N., Norris, J.P., (New York: AIP), p 365 Google Scholar
9. Roques, J.P., Bouchet, L., Jourdain, E., et al., 1994, Ap. J. Supp., 92, 451 CrossRefGoogle Scholar
10. Schönfelder, V., Aarts, H., Bennett, K., et al., 1993, Ap. J. Supp., 86, 657 CrossRefGoogle Scholar
11. Sunyaev, R.A., Titarchuk, L.G., 1980, A&A, 86, 121 Google Scholar
12. Titarchuk, L., 1994, Ap. J., 434, 570 CrossRefGoogle Scholar