Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-26T16:07:21.444Z Has data issue: false hasContentIssue false
  • English
  • Français

ROSAT Observations of Soft X-ray Transients in Quiescence

Published online by Cambridge University Press:  25 May 2016

Frank Verbunt
Frank Verbunt*
Affiliation:
Astronomical Institute, Utrecht University, Postbox 80.000, 3508 TA Utrecht, The Netherlands

Abstract

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.

Four soft X-ray transients, two with a neutron star and two with a black hole, have been detected at quiescence with ROSAT. Blackbody fits to their spectra give temperatures of 160–300 eV, and surface areas of <1 km2. The small surface area suggests that the actual spectrum may be optically thin. The companion star does not contribute significantly to the X-ray luminosity, except perhaps in the case of A 0620-00. From the observation that accretion continues at luminosity levels of ∼1033 erg s−1 it is concluded that the neutron stars in Aql X-1 and Cen X-4 have a weak magnetic field and rotate rather slowly.

Type
5 X-ray Binaries
Information
Symposium - International Astronomical Union , Volume 165: Compact Stars in Binaries , 1996 , pp. 333 - 339
Copyright
Copyright © Kluwer 1996 

References

Czerny, M., Czerny, B. & Grindlay, J.E. 1987, ApJ 312, 122.CrossRefGoogle Scholar
Dempsey, R. et al. 1993, ApJS 86, 599.Google Scholar
Kulkarni, S.R. et al. 1992, in X-ray Binaries and Recycled Pulsars , van den Heuvel, E.P.J. & Rappaport, S. (Eds.), Kluwer Academic Publishers, p. 99.CrossRefGoogle Scholar
Long, K., Helfand, D. & Grabelsky, D. 1981, ApJ 248, 925.Google Scholar
McClintock, J.E. & Remillard, R.E. 1990, ApJ 350, 386.CrossRefGoogle Scholar
McClintock, J.E., Horne, K. & Remillard, R.E. 1995, ApJ (in press).Google Scholar
Mihalas, D. & Binney, J. 1981, Galactic Astronomy, Structure and Kinematics , Freeman, 2nd Edition.Google Scholar
Mineshige, S. et al. 1992, PASJ 44, 117.Google Scholar
Schrijver, C. & Zwaan, C. 1991, A&A 151, 183.Google Scholar
Shahbaz, T., Naylor, T. & Charles, P. 1994, MNRAS 268, 756.CrossRefGoogle Scholar
Stella, L. et al. 1994, ApJ 423, L47.Google Scholar
Tanaka, Y. & Lewin, W.H.G. 1995, in X-ray Binaries , Lewin, W.H.G., van Paradijs, J. & van den Heuvel, E.P.J. (Eds.), Cambridge University Press (in press).Google Scholar
Van Paradijs, J. & Verbunt, F. 1984, in High Energy Transients in Astrophysics , Woosley, S.E. (Ed.), AIP Conf. Proc. Vol. 115, p. 49.Google Scholar
Van Paradijs, J. et al. 1987, A&A 182, 47.Google Scholar
Verbunt, F. 1993, ARA&A 31, 93.Google Scholar
Verbunt, F. et al. 1994, A&A 285, 903.Google Scholar
Wagner, R. et al. 1992, ApJ 401, L97.CrossRefGoogle Scholar
Wagner, R.M. et al. 1994, ApJ 429, L25.Google Scholar
White, N.E., Kaluzienski, L.J. & Swank, J.H. 1984, in High Energy Transients in Astrophysics , Woosley, S.E. (Ed.), AIP Conf. Proc. Vol. 115, p. 31.Google Scholar