A multiwavelength survey of NGC6752: X-ray counterparts, two new dwarf novae and a core-collapsed radial profile

• Published in: Monthly notices of the Royal Astronomical Society Vol. 423; no. 3; pp. 2901 - 2916
• Main Authors: Thomson, G. S, Knigge, C, Dieball, A, Maccarone, T. J, Dolphin, A, Zurek, D, Long, K. S, Shara, M, Sarajedini, A
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 01.07.2012
• Subjects: Astrophysics; Dwarf stars; Supernovae
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2012.21104.x

We present the results of a multiwavelength (far-ultraviolet to I band) survey of the stellar populations of the globular cluster NGC6752, 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 colour-magnitude 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 WD-main-sequence binaries, including CVs. The X-ray sources and WD binary systems are the most centrally concentrated populations, with dynamically estimated characteristic masses >1.1 and >0.8M, respectively. [PUBLICATION ABSTRACT]