Identification of the Low-Mass X-Ray Binary and Faint X-Ray Sources in NGC 6652

We have detected three new X-ray point sources, in addition to the known low-mass X-ray binary (LMXB) X1832-330, in the globular cluster NGC 6652 with a Chandra 1.6 ks HRC-I exposure. Star 49 (MV ~ 4.7), suggested by Deutsch and coworkers as the optical candidate for the LMXB, is identified (<0.″3) not with the LMXB, but with another, newly detected source (B). Using archival Hubble Space Telescope (HST) images, we identify (<0.″3) the LMXB (A) and one of the remaining new sources (C) with blue variable optical counterparts at MV ~ 3.7 and 5.3, respectively. The other new source (D) remains unidentified in the crowded cluster core. In the 0.5-2.5 keV range, assuming a 5 keV thermal bremsstrahlung spectrum and NH = 5.5 × 1020, source A has intrinsic luminosity LX ~ 5.3 × 1035 ergs s-1. Assuming a 1 keV thermal bremsstrahlung spectrum, B has LX ~ 4.1 × 1033 ergs s-1, while C and D have LX ~ 8 × 1032 ergs s-1. Source B is probably a quiescent LMXB, while source C may be either a luminous cataclysmic variable or a quiescent LMXB.

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