5 papers · 1 filter
The concave X-ray spectrum of the blazar ON 231: the signature of intermediate BL Lac objects
G. Tagliaferri, G. Ghisellini, P. Giommi +17
ON 231 was observed with BeppoSAX in May and June 1998, following an exceptional optical outburst which occured in April--May. We measured the X-ray spectrum from 0.1 up to 100 keV…
ISO observations of the BL Lac object PKS 2155-304
E. Bertone, G. Tagliaferri, G. Ghisellini +3
The Infrared Space Observatory (ISO) observed the BL Lac object PKS 2155-304 16 times from 1996, May 7 to June 8, with both the ISOCAM camera and the ISOPHOT photometer, as part of…
X-ray Rapid Variability of MKN 421
A. Treves, Y. H. Zhang, F. Tavecchio +7
We present a detailed Cross Correlation analysis of the light curves of the X-ray bright BL Lac object Mkn 421 observed with SAX period 1997-1998. Monte Carlo simulations ar…
Hour-Scale Multiwavelength Variability in Markarian 421
M. Catanese, I. H. Bond, S. M. Bradbury +36
Markarian 421 was observed for about four days with BeppoSAX and the Whipple Observatory gamma-ray telescope in April 1998. A pronounced, well-defined, flare with hour-scale variab…
The blazar PKS 0528+134: new results from BeppoSAX observations
G. Ghisellini, L. Costamante, G. Tagliaferri +14
BeppoSAX observed 8 times the gamma-ray bright blazar PKS 0528+134 in Feb. and Mar. 1997, during a multiwavelength campaign involving EGRET, onboard CGRO, and ground based telescop…