We observed the superluminal source GRO J1655-40 with ASCA on five occasions from 1994 through 1997. Significant absorption line features were detected in the iron-K band, which are attributable to the resonance absorption lines from helium-like and/or hydrogen iron ions. This gives direct evidence for the presence of highly ionized plasma in a non-spherical configuration in the vicinity of the black hole. The property of the continuum emission is also discussed. The newly discovered jet source XTE J0421+560 (CI Cam) was observed with ASCA on 1998 April 3-4, when it was in outburst. The spectrum can be explained by the emission from a multi-temperature thin-thermal plasma, although additional spectral structure is necessary to reproduce the broad iron-K emission line. Flare-like intensity enhancements were observed below 1 keV. We present the summary of the observational results and their implications.
19th Texas Symposium on Relativistic Astrophysics and Cosmology
- Pub Date:
- December 1998