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Session 68 - Degenerate Stars, Pulsars.
Display session, Thursday, June 11
The Low Mass X-ray Binary (LMXB) in NGC 6652 is one of about 10 bright X-ray sources to have been discovered in Globular Clusters. This LMXB was securely discovered in the ROSAT All-Sky Survey, but is probably identical to the HEAO-1 source whose relatively large error box contained NGC 6652. More recently, a Type I X-ray burst from this LMXB was detected in BeppoSAX WFC data.
Here we report on a serendipitous ASCA observation of this Globular Cluster LMXB, including the detection of a long-duration (>200 s) Type I burst. Our quiescent (non-bursting) spectrum is the best yet obtained for this source, which apparently was at its brightest level recorded to date. We present spectral and timing properties of the quiescent data as well as the spectral evolution of the burst. We present the evidence for a spectral cooling during the burst, which probably did not reach the Eddington luminosity for a 1.4 M_ødot neutron star. We will discuss these results in the context of Globular Cluster LMXBs.
Program listing for Thursday