Identification of Faint Chandra X-ray Sources in the Core-Collapsed Globular Cluster NGC 6752

Abstract

We have searched for optical identifications for 39 Chandra X-ray sources that lie within the 1.9 arcmin half-mass radius of the nearby (d = 4.0 kpc), core-collapsed globular cluster, NGC 6752, using deep Hubble Space Telescope ACS/WFC imaging in B435, R625, and H alpha. Photometry of these images allows us to classify candidate counterparts based primarily on color-magnitude and color-color diagram location. The color-color diagram is particularly useful for quantifying the H alpha line equivalent width. In addition to recovering 11 previously detected optical counterparts, we propose 20 new optical IDs. In total, there are 16 likely or less certain cataclysmic variables (CVs), nine likely or less certain chromospherically active binaries, three galaxies, and three active galactic nuclei (AGNs). The latter three sources, which had been identified as likely CVs by previous investigations, now appear to be extragalactic objects based on their proper motions. As we previously found for NGC 6397, the CV candidates in NGC 6752 fall into a bright group that is centrally concentrated relative to the turnoff-mass stars and a faint group that has a spatial distribution that is more similar to that of the turnoff-mass stars. This is consistent with an evolutionary scenario in which CVs are produced by dynamical interactions near the cluster center and diffuse to larger radius orbits as they age.

arXiv comment26 pages, 18 figures

References in corpus (33)

• The Photometric Performance and Calibration of the HST Advanced Camera For Surveys
• An ACS Survey of Globular Clusters V: Star Catalog for Each Cluster
• Dynamical Formation of Close Binary Systems in Globular Clusters
• A Hydrogen Atmosphere Spectral Model Applied to the Neutron Star X7 in the Globular Cluster 47 Tucanae
• An Exploration of the Paradigm for the 2-3 Hour Period Gap in Cataclysmic Variables
• SDSS unveils a population of intrinsically faint cataclysmic variables at the minimum orbital period
• Post-common-envelope binaries from SDSS. XI: The white dwarf mass distributions of CVs and pre-CVs
• Analysis of the Quiescent Low-Mass X-ray Binary Population in Galactic Globular Clusters
• The Frequency of Binary Stars in the Core of 47 Tucanae
• Formation and evolution of compact binaries in globular clusters: I.Binaries with white dwarfs
• Dynamical Formation of Close Binaries in Globular Clusters II: Cataclysmic Variables
• The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters
• Stellar Encounter Rate in Galactic Globular Clusters
• X-ray Processing of ChaMPlane Fields: Methods and Initial Results for Selected Anti-Galactic Center Fields
• Optical Identification of Multiple Faint X-ray Sources in the Globular Cluster NGC 6752: Evidence for Numerous Cataclysmic Variables
• X-Ray Observations of Black Widow Pulsars
• An Extensive Census of HST Counterparts to Chandra X-ray Sources in the Globular Cluster 47 Tucanae. II. Time Series and Analysis
• The puzzling dynamical status of the core of the globular cluster NGC 6752
• A Chandra X-ray Observatory Study of PSR J1740--5340 and Candidate Millisecond Pulsars in the Globular Cluster NGC 6397
• Chandra X-ray Observations of 12 Millisecond Pulsars in the Globular Cluster M28
• Identification of Faint Chandra X-ray Sources in the Core-Collapsed Globular Cluster NGC 6397: Evidence for a Bimodal Cataclysmic Variable Population
• Atomic Diffusion and Mixing in Old Stars V: A deeper look into the Globular Cluster NGC 6752
• Resolving the Controversy Over the Core Radius of 47 Tucanae (NGC 104)
• Inside catalogs: a comparison of source extraction software
• X-ray and optical observations of M55 and NGC 6366: evidence for primordial binaries
• A Chandra Look at the X-ray Faint Millisecond Pulsars in the Globular Cluster NGC 6752
• Dynamical Formation of Cataclysmic Variables in Globular Clusters
• HST/ACS Imaging of Omega Centauri: Optical Counterparts of Chandra X-Ray Sources
• Hα photometry of low mass stars in 47 Tucanae: chromospheric activity and exotica
• Timing of millisecond pulsars in NGC 6752 - II. Proper motions of the pulsars in the cluster outskirts
• MOCCA-SURVEY database I. Accreting white dwarf binary systems in globular clusters -- II. Cataclysmic variables -- progenitors and population at birth
• A multi-wavelength survey of NGC\,6752: X-ray counterparts, two new dwarf novae, and a core-collapsed radial profile
• A far-ultraviolet variable with an 18-minute period in the globular cluster NGC 1851

Cited by in corpus (16)

• MOCCA-SURVEY database I. Accreting white dwarf binary systems in globular clusters -- IV. cataclysmic variables -- properties of bright and faint populations
• New Cataclysmic Variables and other Exotic Binaries in the Globular Cluster 47 Tucanae
• A Deep X-ray Survey of the Globular Cluster Omega Centauri
• The MAVERIC Survey: Chandra/ACIS Catalog of Faint X-ray sources in 38 Galactic globular clusters
• A stellar census in globular clusters with MUSE: A spectral catalogue of emission-line sources
• Exploring the Mass Segregation Effect of X-ray Sources in Globular Clusters: The Case of 47 Tucanae
• A Deep Search for Faint Chandra X-ray Sources, Radio Sources, and Optical Counterparts in NGC 6752
• A deep Chandra survey for faint X-ray sources in the Galactic globular cluster M30, and searches for optical and radio counterparts
• Formation and Evolution of Accreting Compact Objects
• Identifications of Faint Chandra Sources in the Globular Cluster M3
• Exotica in the Globular Cluster M4, Studied with Chandra, HST, and the VLA
• X-ray sources in Galactic globular clusters and old open clusters
• Investigating the UV-excess in star clusters with $N$-body simulations: predictions for future CSST observations
• Reevaluating the Origin of Detectable Cataclysmic Variables in Globular Clusters: Testing the Importance of Dynamics
• Exploration of faint X-ray and radio sources in the massive globular cluster M14: A UV-bright counterpart to Nova Ophiuchus 1938
• Are most Cataclysmic Variables in Globular Clusters dynamically formed?