X-ray spectra and flux variations of blazars, 3C 279, Mkn 421, PKS 2155-304, BL Lac 0716+714, and OJ 287 were observed by ASCA. The X-ray light curve of 3C 279 showed correlated variation with 22 and 33 GHz radio flux during 1987-1991, but from 1993 to 1995, radio flux was in the highest level, while the X-ray flux was in the lowest level. X-rays from Mkn 421 were observed simultaneously with TeV gamma-ray observations at Whipple Observatory and a coincident flare was detected. The X-ray flux of PKS 2155-304 was in high state in 1994 and the absorption feature at around 0.6 keV was not observed. Spectral indices of PKS 2155-304 and Mkn 421 varied in correlated way with the flux and showed looping in the index-flux plane. The spectra of BL Lac 0716+714 were of single power law type with photon index of -2.62 and of double power law type with steep low energy component. OJ 287 was in low state and a flat power law spectrum with photon index of -1.75 was observed.
Roentgenstrahlung from the Universe
- Pub Date:
- February 1996
- Blazars: X Rays