Identification of the Low‐Mass X‐Ray Binary and Faint X‐Ray Sources in NGC 6652
- 20 November 2001
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 562 (1) , 363-367
- https://doi.org/10.1086/323493
Abstract
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 ksec HRC-I exposure. Star 49 (M_{V}~4.7), suggested by Deutsch et al.(1998) as the optical candidate for the LMXB, is identified (<0.3") not with the LMXB, but with another, newly detected source (B). Using archival HST images, we identify (<0.3") the LMXB (A) and one of the remaining new sources (C) with blue variable optical counterparts at M_{V}~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 N_{H}=5.5*10^{20}, source A has intrinsic luminosity L_{X}~5.3*10^{35} ergs/s. Assuming a 1 keV thermal bremsstrahlung spectrum, B has L_{X}~4.1*10^{33} ergs/s, while C and D have L_{X}~8*10^{32}$ ergs/s. Source B is probably a quiescent LMXB, while source C may be either a luminous CV or quiescent LMXB.Comment: 14 pages, 3 figures, accepted by Astrophysical JournaKeywords
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