123 citations · 262 across the 5 of their papers we have counts for
5 papers · 1 filter
X-ray bright optically quiet galaxies: the case of P3
A. Comastri, M. Brusa, P. Ciliegi +10
Recent X-ray surveys have clearly demonstrated that a population of optically dull, X-ray bright galaxies is emerging at X-ray fluxes of the order of 10-14 erg cm-2 s-1. The nature…
On the nature of X-ray absorption in Seyfert 2 galaxies
M. Guainazzi, F. Fiore, G. Matt +1
We have studied the correlation among X-ray absorption, optical reddening and nuclear dust morphology in Seyfert 2 galaxies. Two main conclusions emerge: a) the Balmer decrement an…
High Energy Large Area Surveys: from BeppoSAX to Chandra and XMM
F. Fiore, A. Comastri, F. La Franca +3
Optical identification of hard X-ray selected BeppoSAX and Chandra sources indicates that a large fraction of the sources are ``intermediate'' AGN, i.e. type 1.8-1.9 AGN, broad-lin…
Broad band spectrum of Cygnus X-1 in two spectral states with BeppoSAX
F. Frontera, E. Palazzi, A. A. Zdziarski +13
We report on the 0.5--200 keV spectral properties of Cyg X-1 observed at different epochs with the Narrow Field Instruments of the BeppoSAX satellite. The source was in its soft st…
Ionized Absorbers in AGN: the Role of Collisional Ionization and Time-Evolving Photoionization
F. Nicastro, F. Fiore, G. C. Perola +1
In this paper we explore collisional ionization and time-evolving photoionization in the, X-ray discovered, ionized absorbers in Seyfert galaxies. These absorbers show temporal cha…