51 citations · 56 across the 6 of their papers we have counts for
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AGN models for the X and gamma-ray backgrounds
Andrea Comastri
The origin of the X-ray background spectral intensity has been a long standing problem in high energy astrophysics research. Deep X-ray surveys carried out with ROSAT and ASCA comb…
The BeppoSAX High Energy Large Area Survey (HELLAS)
F. Fiore, P. Giommi, F. La Franca +9
We have surveyed about 50 deg-2 of sky in the largely unexplored 5-10 keV band using the BeppoSAX MECS instrument, finding 180 sources. After correction for the non uniform sky cov…
The colours of the X-ray background
A. Comastri
The recent deep X-ray surveys at both soft (0.5--2 keV) and hard (2--10 keV) energies have greatly extended our knowledge of the X-ray source density and spectral shapes at relativ…
First ASCA results for high-redshift Radio-Quiet Quasars
C. Vignali, A. Comastri, M. Cappi +2
Here we report the X-ray spectral analysis of 5 high-redshift () radio-quiet quasars (RQQs) observed with the ASCA satellite. A simple power law with Galactic absorption…
Evidence for inverse Compton emission in the powerful radio galaxy 3C 219
G. Brunetti, A. Comastri, G. Setti +1
Spectral analysis of ROSAT PSPC and ASCA archive data and a recent ROSAT HRI observation of the powerful FRII radio galaxy 3C 219 reveal an absorbed point-like source, coincident w…
BeppoSax Spectral Survey of soft X-ray selected BL Lacs
A. Wolter, A. Comastri, G. Ghisellini +10
We present X-ray spectra obtained with BeppoSAX (Satellite per Astronomia X) of 10 BL Lac objects, selected from the Einstein Medium Sensitivity and Slew Surveys. We find that in a…