A Chandra Observation of the Diffuse Emission Centered on the Low-Mass X-Ray Binary 4U 1755-33

We present an analysis of a Chandra observation of the field surrounding the low-mass X-ray binary 4U 1755-33, which has been in quiescence since 1996. In 2003, Angelini & White reported the appearance of a narrow 7'-long jetlike feature centered on the position of 4U 1755-33 using the XMM-Newton telescope. Although the source and jet are not visibly apparent in our Chandra ACIS-S image, there is a significant excess (4-6 σ) of counts in a region that encloses the jet when compared to adjacent regions. We examined a knot of emission in the jet that was detected by XMM-Newton but not by Chandra and calculated that if the knot flux observed by XMM-Newton was concentrated in a point source, Chandra would have easily detected it; we therefore conclude that this knot of emission is diffuse. In summary, we suggest that the jetlike feature found previously in the XMM-Newton data is quite diffuse and likely a true jet and that it is not due to a chance alignment of discrete point sources or pointlike regions of emission associated with internal shocks.