Properties of the second outburst of the bursting pulsar (GRO J1744-28) asobserved with BATSE

One year after its discovery, the Bursting Pulsar (GRO J1744-28) went into outburst again, displaying the hard X-ray bursts and pulsations that make t his source unique. We report on BATSE observations of both the persistent a nd burst emission for this second outburst and draw comparisons with the fi rst. The second outburst was smaller than the first in both duration and pe ak luminosity. The persistent flux, burst peak flux, and burst fluence were all reduced in amplitude by a factor of similar to 1.7. Despite these diff erences, the two outbursts were very similar with respect to the burst occu rrence rate, the durations and spectra of bursts, the absence of spectral e volution during bursts, and the evolution of the ratio ct of average persis tent to burst luminosity. Although no spectral evolution was found within i ndividual bursts, we find evidence for a small (20%) variation of the spect ral temperature during the course of the second outburst.