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BeppoSAX study of the X-ray binary XB 1832-330 located in the globular cluster NGC 6652

A. N. Parmar·T. Oosterbroek·L. Sidoli·L. Stella·F. Frontera
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Abstract

Results of a 2001 March 17-20 BeppoSAX observation of the X-ray binary XB 1832-330 located in the globular cluster NGC 6652 are presented. In contrast to the majority of luminous globular cluster X-ray sources, the (0.1-200 keV) BeppoSAX spectrum cannot be fit with a disk-blackbody and comptt Comptonization model, unless partial covering is included. This confirms the ASCA detection of partial covering by Mukai & Smale (2000). The best-fit spectral parameters are similar to those of the globular cluster sources with orbital periods of <1 hr, implying that XB 1832-330 is also an ultra-compact system. A plausible optical candidate to XB 1832-330 has recently been discovered by Heinke et al. (2001) which shows evidence for possible 0.92, 2.22, or 4.44 hr periodicities. We find no evidence for any 2-10 keV periodic modulation at any of these periods with a 2 sigma upper limit to the semi-amplitude of any sinusoid of < 1.5%.

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A. N. Parmar, T. Oosterbroek, L. Sidoli, L. Stella, F. Frontera. 2001-10-22. BeppoSAX study of the X-ray binary XB 1832-330 located in the globular cluster NGC 6652. https://doi.org/10.1051/0004-6361%3A20011464

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