An XMM-Newton observation of the neutron star X-ray transient 2S 1803-245 in quiescence

Abstract

We observed the neutron star X-ray transient 2S 1803-245 in quiescence with the X-ray satellite XMM-Newton, but did not detect it. An analysis of the X-ray bursts observed during the 1998 outburst of 2S 1803-245 gives an upper limit to the distance of <=7.3 kpc, leading to an upper limit on the quiescent 0.5-10 keV X-ray luminosity of <=2.8 × 10³² erg s^-1 (3σ). Since the expected orbital period of 2S 1803-245 is several hours, this limit is not much higher than those observed for the quiescent black hole transients with similar orbital periods.