An XMM-Newton Observation of 4U1755-33 in Quiescence: Evidence for a Fossil X-Ray Jet

Abstract

We report an XMM-Newton observation of the Low mass X-ray Binary (LMXB) and black hole candidate 4U1755-33. This source had been a bright persistent source for at least 25 yrs, but in 1995 entered an extended quiescent phase. 4U1755-33 was not detected with an upper limit to the 2-10 keV luminosity of 5.10^31 erg/s (assuming a distance of 4 kpc) - consistent with the luminosity of other black hole candidates in a quiescent state. An unexpected result is the discovery of a narrow 7' long X-ray jet-like feature centered on the position of 4U1755-33. The spectrum of the jet is similar to that observed from other galactic and extragalactic jets thought to be associated with accreting black holes. The detection of a fossil jet provides additional evidence supporting the black hole candidacy of 4U1755-33. The spectral properties of three bright serendipitous sources in the field are reported and it is suggested these are background active galactic nuclei (AGN).