Globular clusters as a source of X-ray emission from the neighbourhood of M87
Abstract
AT least five galactic X-ray sources have been identified with globular clusters1-3, and it is possible that a similar association holds for the bright unidentified sources near the galactic centre4. Intense X-ray bursts have been detected5 from the direction of one of these (3U1820-30/NGC 6624), and a star cluster, probably globular, has been found6 in the error box7,8 of the so-called `rapid burster', MXB1730-335. Moreover, the error box of a hard X-ray flare observed from the Cosmos 428 satellite9 contains NGC5904 (M5). This globular cluster has similar properties10 to the others that emit X rays, and if normally weak it is unlikely to have appeared in the Uhuru catalogue because of its position. The X-ray emission from globular clusters may be attributable to accretion on to compact objects, the accreting material being supplied from binary companions11-14, or gas trapped in the potential well of the cluster15,16.
- Publication:
-
Nature
- Pub Date:
- September 1976
- DOI:
- 10.1038/263301b0
- Bibcode:
- 1976Natur.263..301F
- Keywords:
-
- Galactic Radiation;
- Globular Clusters;
- X Ray Sources;
- Galactic Nuclei;
- Milky Way Galaxy;
- Stellar Luminosity;
- Astrophysics