Uhuru observations of 4U 1608-52: the "steady" X-ray source associated with the X-ray burst source in Norma.
Abstract
Data are presented for the X-ray source 4U 1608-52, summarizing its light curve, location, and spectral parameters. Evidence is presented showing that this source is the 'steady' X-ray counterpart of the X-ray burst source in Norma. The spectrum of the 'steady' source is compared with the spectrum observed during two bursts, and it is noted that there is substantially more low-energy absorption during the bursts. The 'steady' source spectral data are used to examine the optical data, and it is concluded that if the X-ray spectrum is thermal, then a globular-cluster counterpart probably would have been detected (whereas none has been). Further X-ray and optical observations are suggested for this source, since an optical identification may be central in determining whether all X-ray bursts have a common origin and if this origin requires a globular-cluster environment.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1976
- DOI:
- 10.1086/182282
- Bibcode:
- 1976ApJ...209L.125T
- Keywords:
-
- Globular Clusters;
- Light Curve;
- Uhuru Satellite;
- X Ray Sources;
- Spaceborne Astronomy;
- X Ray Astronomy;
- X Ray Spectra;
- Astronomy