A multiwavelength survey of NGC 6752: X-ray counterparts, two new dwarf novae and a core-collapsed radial profile

作者：Thomson G S^*; Knigge C; Dieball A; Maccarone T J; Dolphin A; Zurek D; Long K S; Shara M; Sarajedini A

来源：Monthly Notices of the Royal Astronomical Society, 2012, 423(3): 2901-2916.

DOI：10.1111/j.1365-2966.2012.21104.x

• binaries: close
• stars: dwarf novae
• novae, cataclysmic variables
• stars: variables: general
• globular clusters: individual: NGC 6752

We present the results of a multiwavelength (far-ultraviolet to I band) survey of the stellar populations of the globular cluster NGC 6752, using Space Telescope Imaging Spectrograph (STIS), Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. We have confirmed that two previously identified cataclysmic variable (CV) candidates are, in fact, dwarf novae which underwent outbursts during our observations. We have also identified previously unknown optical counterparts to two X-ray sources. We estimate the position of the centre of the cluster, and show that the stellar density profile is not well described by a single King model, indicating that this cluster is in a core-collapsed or post-core-collapse phase. The colourmagnitude diagram shows a well-populated horizontal branch, numerous blue stragglers and white dwarfs (WDs), as well as 87 sources in the gap region where we expect to find WDmain-sequence binaries, including CVs. The X-ray sources and WD binary systems are the most centrally concentrated populations, with dynamically estimated characteristic masses %26gt;1.1 and %26gt;0.8 M?, respectively.

• 出版日期2012-7