A persistent hard X-ray emission has been observed by the SIGMA telescope in the Terzan 1 globular cluster. The photon spectrum is reproduced by a power law with spectral index equal to -3.2+/-0.7. The luminosity calculated in the 40-75keV energy range assuming a distance of 10kpc is equal to (4+/-0.8) 10^35^erg/s. This source is already known as an X-ray burster and has been studied by HEAO1, SL2-XRT, Exosat, Rosat and ART-P and it may be a LMXB with a neutron star as the compact member.
Astronomy and Astrophysics Supplement Series
- Pub Date:
- December 1996
- GLOBULAR CLUSTERS: INDIVIDUAL: TERZAN 1;
- GAMMA-RAYS: OBSERVATIONS