Detection of an ultraviolet and visible counterpart of the NGC 6624 X-ray burster

Abstract

view Abstract Citations (44) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Detection of an Ultraviolet and Visible Counterpart of the NGC 6624 X-Ray Burster King, I. R. ; Stanford, S. A. ; Albrecht, R. ; Barbieri, C. ; Blades, J. C. ; Boksenberg, A. ; Crane, P. ; Disney, M. J. ; Deharveng, J. M. ; Jakobsen, P. ; Kamperman, T. M. ; Macchetto, F. ; Mackay, C. D. ; Paresce, F. ; Weigelt, G. ; Baxter, D. ; Greenfield, P. ; Jedrzejewski, R. ; Nota, A. ; Sparks, W. B. ; Sosin, C. Abstract We have detected, in images taken with the HST FOC, the UV and optical counterpart of the X-ray source 4U 1820-30 in the globular cluster NGC 6624. Astrometric measurements place this object 2 sigma from the X-ray position of 4U 1820-30. The source dominates a far-UV FOC image and has the same flux at 1400 A as was seen through the large IUE aperture by Rich et al. (1993). It has a B magnitude of 18.7 but is not detected in V. It is 0.66 arcsec from the center of NGC 6624, a fact that may change the interpretation of the P-average of the 11 minute binary orbit. The flux drops between 1400 and 4300 A at a rate that is nearly as steep as that of a Rayleigh-Jeans curve. The flux is far too large to come from the neutron star directly but could accord with radiation from a heated accretion disk and/or the heated side of the companion star. Publication: The Astrophysical Journal Pub Date: August 1993 DOI: 10.1086/186973 Bibcode: 1993ApJ...413L.117K Keywords: Globular Clusters; Iue; Ultraviolet Astronomy; X Ray Sources; Astrometry; Neutron Stars; Visible Spectrum; Astrophysics full text sources ADS | data products SIMBAD (2) MAST (2) ESA (1)