EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 390/2 Article
Free access article

Issue A&A
Volume 390, Number 2, August I 2002
Page(s) 597 - 609
Section Formation, structure and evolution of stars
DOI http://dx.doi.org/10.1051/0004-6361:20020762



A&A 390, 597-609 (2002)
DOI: 10.1051/0004-6361:20020762

The nature of the X-ray transient SAX J1711.6-3808

J. J. M. in 't Zand1, 2, C. B. Markwardt3, 4, A. Bazzano5, M. Cocchi5, R. Cornelisse1, 2, J. Heise2, E. Kuulkers1, 2, L. Natalucci5, M. Santos-Lleo6, J. Swank4 and P. Ubertini5

1  Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands
2  SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
3  Dept. of Astronomy, University of Maryland, College Park, MD 20742, USA
4  NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771, USA
5  Istituto di Astrofisica Spaziale (CNR), Area Ricerca Roma Tor Vergata, Via del Fosso del Cavaliere, 00133 Roma, Italy
6  XMM-Newton Science Operations Center, Vilspa Satellite Tracking Station, Apartado 50727, 28080 Madrid, Spain

(Received 1 March 2002 / Accepted 15 May 2002)

Abstract
SAX J1711.6-3808 is an X-ray transient in the Galactic bulge that was active from January through May of 2001 and whose maximum 1-200 keV luminosity was measured to be $5\times 10^{-9}$ erg cm -2 s -1 which is less than ~25% of the Eddington limit, if placed at a distance equal to that of the galactic center. We study the X-ray data that were taken of this moderately bright transient with instruments on BeppoSAX and RXTE. The spectrum shows two interesting features on top of a Comptonized continuum commonly observed in low-state X-ray binaries: a broad emission feature peaking at 7 keV and extending from 4 to 9 keV, and a soft excess with a color temperature below 1 keV which reveals itself only during one week of data. High time-resolution analysis of 412 ksec worth of data fails to show bursts, coherent or high-frequency quasi-periodic oscillations. Given the dynamic range of the flux measurements, this would be unusual if a neutron star were present. SAX J1711.6-3808 appears likely to contain a black hole. No quiescent optical counterpart could be identified in archival data within the 5´´-radius XMM error circle, but the limits are not very constraining because of heavy extinction ( A V=16).


Key words: accretion, accretion disks -- binaries: close -- X-rays: stars: individual: SAX J1711.6-3808

Offprint request: J. J. M. in 't Zand, jeanz@sron.nl

SIMBAD Objects



© ESO 2002


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.