X-ray properties of 4U 1543-624
Abstract
4U 1543-624 is a relatively bright persistent low-mass X-ray binary. Analysis of archival data from ASCA, SAX and RXTE is presented. The X-ray continuum be can modeled with the standard low-mass X-ray binary spectrum, an isothermal blackbody and a Comptonized component. Variations in the luminosity and flux ratio of the continuum components are seen. An increase in luminosity is accompanied by a decrease in the blackbody luminosity and a hardening of the spectrum. Most low-mass X-ray binaries have softer spectra and higher blackbody luminosities in high luminosity states. The Fe Kalpha line is seen only in the high luminosity spectra. A narrow feature near 0.7 keV, previously detected in the ASCA data, is also seen in the SAX data. A qualitative model of the system is presented. The X-ray observations can be explained by a low inclination system (face-on disk) containing a slowly (P >> ms) rotating neutron star. A slowly rotating neutron star would imply either that the system is a young low-mass X-ray binary, or that the accretion rate is unusually low. The empirical relation between optical and X-ray luminosity and orbital period suggests a relatively short period.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 2003
- DOI:
- 10.1051/0004-6361:20021477
- arXiv:
- arXiv:astro-ph/0210250
- Bibcode:
- 2003A&A...397..249S
- Keywords:
-
- binaries: close;
- stars: individual: 4U 1543-624;
- X-rays: binaries;
- Astrophysics
- E-Print:
- 9 pages, 3 figures, accepted for publication in A&