20 citations · 25 across the 14 of their papers we have counts for
5 papers · 2 filters
The evolution of AGN in the Hard X-rays from HELLAS
F. La Franca, F. Fiore, C. Vignali +3
We present optical spectroscopic identification of sources identified in the BeppoSAX MECS fields of the High Energy LLarge Area Survey (HELLAS). In total 62 sources from a sample…
On the peculiar X-ray properties of the bright nearby radio-quiet quasar PDS456
C. Vignali, A. Comastri, F. Nicastro +3
BeppoSAX and ASCA observations of the nearby (z=0.184), high-luminosity, radio-quiet quasar PDS456 are presented. The X-ray spectrum is characterized by a prominent ionized edge at…
Sub-mm and X-ray background: two unrelated phenomena?
P. Severgnini, R. Maiolino, M. Salvati +9
Obscured AGNs are thought to contribute a large fraction of the hard X-ray background (2-10 keV), and have also been proposed as the powerhouse of a fraction of the SCUBA sources w…
Optically dim counterparts of hard X-ray selected AGNs
R. Maiolino, M. Salvati, L. A. Antonelli +9
We present near-IR photometry and imaging observations of a small sample of sources identified in the BeppoSAX 5-10 keV survey (HELLAS) which resolves ~ 20-30% of the X-ray backgro…
The BeppoSAX High Energy Large Area Survey (HELLAS): a progress Report
A. Comastri, F. Fiore, C. Vignali +2
The integrated emission of highly obscured AGN is expected to provide a major contribution to the X-ray energy density in the Universe: the X-ray background (XRB). The study of the…