RX J004717.4-251811: The first eclipsing X-ray binary outside the Local Group

Free access article

Issue		A&A Volume 402, Number 2, May I 2003


Page(s)		457 - 464
Section		Galactic structure and dynamics
DOI		http://dx.doi.org/10.1051/0004-6361:20030274

A&A 402, 457-464 (2003)
DOI: 10.1051/0004-6361:20030274

RX J004717.4-251811: The first eclipsing X-ray binary outside the Local Group

W. Pietsch, F. Haberl and A. Vogler

Max-Planck-Institut für extraterrestrische Physik, 85741 Garching, Germany
(Received 19 December 2002 / Accepted 25 February 2003 )

Abstract
The X-ray source RX J004717.4-251811 in the nearby starburst galaxy NGC 253 was found to undergo changes from a low to a high state twice, during an XMM-Newton EPIC observation in December 2000 and also during a Chandra observation one year earlier. These transitions are interpreted as egresses from eclipses of a compact object in a high mass X-ray binary system (HMXB). The phase of eclipse egress during the Chandra observation is given by barycenter corrected $\rm MJD~51539.276\pm 0.006$ and the binary period determined to $p=(352.870\pm 0.012){\rm d}/n$ by the time difference between the two egresses and number n of periods in-between. Allowed periods may be further constrained by additional XMM-Newton, Chandra, ROSAT, and Einstein observations resulting in only seven acceptable periods with 1.47024 d and 3.20793 d most promising. No significant regular pulsations of the source in the range 0.3-1000 s were found. Fluctuations on time scales of 1000 s were observed together with extended intervals of low intensity. The energy spectrum during the bright state can best be described by an absorbed flat power law ( = 1.9 $\,\times\,10^{21}$ cm ^-2, $\Gamma=1.7$ ). In the bright state the source luminosity is $4\times 10^{38}$ (0.5-5 keV), just compatible with the Eddington luminosity of a 1.4 $M_{\odot}$ neutron star. A possible optical identification is suggested. RX J004717.4-251811 parameters are compared to other eclipsing X-ray binaries (XRBs).

Key words: galaxies: individual: NGC 253 -- X-rays: stars -- stars: binaries: eclipsing

Offprint request: W. Pietsch, wnp@mpe.mpg.de

SIMBAD Objects

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.