Search for radio pulsations in four Anomalous X-ray Pulsars and discovery of two new pulsars

Abstract

We report on observations of four southern Anomalous X-ray Pulsars (1RXSJ170849.0-400910, 1E1048.1-5937, 1E1841-045 and AXJ1845-0258) obtained at 1.4 GHz using the Parkes Radio Telescope. Radio pulsations from these sources have been searched (i) by directly folding the time-series at a number of trial periods centred on the value of the spin rate obtained from the X-ray observations; (ii) by performing a blind search and (iii) by using a code sensitive to single de-dispersed pulses, with the aim to detect signals similar to those of the recently discovered Rotating Radio Transients. No evidence for radio pulsations with an upper limit of ~0.1mJy for any of the four targets has been found. The blind search led to the serendipitous discovery of two new pulsars, rotating with a spin period of about 0.7s and 92ms, respectively, and to the further detection of 18 known pulsars, two of which were also detected in the single-pulse search.