Optical/near-infrared observations of GRO J1744-28

Abstract

We present results from a series of optical (g- and r-band) and near-infrared (K′-band) observations of the region of the sky including the entire Rossi X-Ray Timing Explorer and ROSAT error circles for the "Bursting Pulsar," GRO J1744-28. These data were taken with the Astrophysical Research Consortium's 3.5 m telescope at Apache Point Observatory and with the 2.2 m telescope at the European Southern Observatory. We see no new object, or any significant brightening of any known object, in these error circles, with the exception of an object detected in our 1996 February 8 image. This object has already been proposed as a near-infrared counterpart to GRO J1744-28. While it is seen in only two of our 10 frames from February 8, there is no evidence that this is an instrumental artifact, suggesting the possibility of near-infrared flares from GRO J1744-28, similar to those that have been reported from the Rapid Burster. The distance to the Bursting Pulsar must be more than 2 kpc, and we suggest that it is more than 7 kpc. Show more