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

TL;DR

This study used XMM-Newton to observe the neutron star transient 2S 1803-245 in quiescence but did not detect it, establishing upper limits on its distance and X-ray luminosity, which are comparable to black hole transients with similar orbital periods.

Contribution

First X-ray observation of 2S 1803-245 in quiescence setting upper limits on its luminosity and distance, informing comparisons with black hole transients.

Findings

No detection of 2S 1803-245 in quiescence.

Upper limit on distance: <7.3 kpc.

Upper limit on X-ray luminosity: <2.8x10^32 erg/s.

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 <2.8x10^32 erg/s (3sigma). Since the expected orbital period of 2S 1803-245 is several hrs, this limit is not much higher than those observed for the quiescent black hole transients with similar orbital periods.