6 papers
EVN Observations of the BL Lac object ON 231
F. Mantovani, E. Massaro, R. Fanti +3
New EVN images at 5.0 GHz and 8.4 GHz of ON 231 confirm the complex structure of the source, the identification of the core, the presence of components on the two sides of the core…
Discovery, identification, and study of variability in gamma-ray point sources
M. Fiorucci, N. Marchili, G. Tosti +3
We present preliminary results of a statistical analysis obtained with a sample of blazars observed at the Perugia Astronomical Observatory since 1992. We briefly show how these st…
Optical Observations of Blazars: the Perugia Monitoring
G. Tosti, S. Ciprini, G. Nucciarelli
In eight years, during the blazar monitoring program performed with the Perugia automatic telescope, we were able to collect about 20000 photometric points, contributing…
Two BeppoSAX observations of BL Lac
G. Tagliaferri, G. Ghisellini, M. Ravasio +14
We present the results of two ToO BeppoSAX observations of BL Lac. During the first observation we detected both the synchrotron and the Compton components. Fast time variability w…
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…
Synchrotron and Inverse Compton Variability in the BL Lacertae object S5 0716+714
P. Giommi, E. Massaro, L. Chiappetti +14
We report intensity variations of different spectral components in the BL Lac object S5 0716+714 detected during coordinated BeppoSAX and optical observations in 1996 and 1998. The…