5 papers · 1 filter
The obscured X-ray source population in the HELLAS2XMM survey: the Spitzer view
C. Vignali, Francesca Pozzi, A. Comastri +9
Recent X-ray surveys have provided a large number of high-luminosity, obscured Active Galactic Nuclei (AGN), the so-called Type 2 quasars. Despite the large amount of multi-wavelen…
The obscured quasar population from optical, mid-infrared, and X-ray surveys
C. Vignali, A. Comastri, D. M. Alexander
Over the last few years, optical, mid-infrared and X-ray surveys have brought to light a significant number of candidate obscured AGN and, among them, many Type 2 quasars, the long…
The quest for Type 2 quasars: Chandra observations of luminous obscured quasars in the Sloan Digital Sky Survey
C. Vignali, D. M. Alexander, A. Comastri
We report on new Chandra exploratory observations of six candidate Type 2 quasars at z=0.49-0.73 selected among the most [OIII] luminous emitters from the Sloan Digital Sky Survey…
Type II quasar candidates in the Sloan Digital Sky Survey: evidence for X-ray obscuration
C. Vignali, D. M. Alexander, A. Comastri
Recent X-ray surveys with Chandra and XMM-Newton have found several genuine Type II quasars, the long sought-after population of high-luminosity (high-redshift) Seyfert 2 galaxies,…
The HST snapshot survey of the B2 sample of low luminosity radio-galaxies: a picture gallery
A. Capetti, H. R. de Ruiter, R. Fanti +3
A Hubble Space Telescope snapshot survey of the B2 sample of low luminosity radio galaxies has, at present, produced V and I images of 41 objects. Together with 16 images of B2 sou…