Ultraviolet-excess selection of the counterpart to a globular cluster X-ray burster - Hubble Space Telescope images of the core of NGC 6712

Abstract

view Abstract Citations (31) References (27) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Ultraviolet-Excess Selection of the Counterpart to a Globular Cluster X-Ray Burster: Hubble Space Telescope Images of the Core of NGC 6712 Anderson, Scott F. ; Margon, Bruce ; Deutsch, Eric W. ; Downes, Ronald A. Abstract Using the Planetary Camera on the Hubble Space Telescope, we have obtained high spatial resolution, multicolor images and photometry of the core of the globular cluster NGC 6712. A comparison of our blue and ultraviolet images unambiguously reveals a faint (B = 21), UV-excess object, 'star S', within the Einstein error box for the bursting X-ray source X1850-086. The unusual color of star S is immediately apparent even in a cursory visual comparison of the images, and is more quantitatively (U-B of about -1) confirmed via photometry. A variety of different candidate optical counterparts to the X-ray source have previously been suggested from ground-based work, but our images indicate that star S is almost certainly the only viable candidate brighter than U = 21. Compared with the mean values for low mass X-ray binaries in the field, star S has a typical (U-B) color, and a moderate-to-high X-ray-to-optical luminosity ratio, but its luminosity (MB = 5) is about 4 mag fainter than average. Publication: The Astronomical Journal Pub Date: September 1993 DOI: 10.1086/116702 Bibcode: 1993AJ....106.1049A Keywords: Globular Clusters; Hubble Space Telescope; Ultraviolet Astronomy; X Ray Sources; Astrometry; Color-Magnitude Diagram; Image Analysis; Spaceborne Astronomy; Stellar Luminosity; Stellar Spectrophotometry; Astronomy; GLOBULAR CLUSTERS: INDIVIDUAL: NGC 6712; X-RAYS: BURSTS; X-RAYS: STARS full text sources ADS | data products SIMBAD (12) MAST (1) ESA (1)