Using mid-infrared and radio selection criteria, we pre-select a sample of candidate high-redshift type-2 quasars in the Subaru XMM-Newton Deep Field (SXDF). To filter out starburst contaminants, we use a bayesian method to fit the spectral energy distributions (SEDs) between 24-microns and B-band, obtain photometric redshifts, and identify the best candidates for high-z type-2 quasars. This leaves us with 12 z_phot >= 1.7 type-2 quasar candidates in an area ~0.8 deg^2, of which only two have secure X-ray detections. The two detected sources have estimated column densities N_H~2 and 3x10^27 m^-2, i.e. heavily obscured but Compton-thin quasars. Given the large bolometric luminosities and redshifts of the undetected objects, the lack of X-ray...
Many models that seek to explain the origin of the unresolved X-ray background predict that Compton-...
Context. Obscured AGN are fundamental to understand the history of supermassive black hole growth an...
We present X-ray spectral analysis of the brightest sources ($f_{2{-}10~{\rm keV}} > 10^{-15}$ $\rm...
Using mid-infrared and radio selection criteria, we pre-select a sample of candidate high-redshift t...
Using mid-infrared and radio selection criteria, we pre-select a sample of candidate high-redshift t...
Using mid-infrared and radio criteria, we select a sample of candidate z~2 obscured quasars. Optical...
This thesis presents a study of high-redshift obscured (type-2) quasars, selected at mid-infrared an...
The intrinsic column density (N-H) distribution of quasars is poorly known. At the high obscuration ...
We present new mid-infrared and submillimetre observations for a sample of eight high redshift type-...
XMM-Newton observations of 29 high redshift (z>2) quasars, including seven radio-quiet, 16 radio-lou...
Quasars with extremely red infrared-to-optical colours are an interesting population that can test i...
Using the large multiwavelength data set in the Chandra/SWIRE Survey (0.6 deg2 in the Lockman Hole),...
Quasars may have played a key role in limiting the stellar mass of massive galaxies. Identifying tho...
Using the large multiwavelength data set in the Chandra/SWIRE Survey (0.6 deg2 in the Lockman Hole),...
Obscured quasars hidden in deep X-ray surveys can be recovered by looking at mid-infrared wavelength...
Many models that seek to explain the origin of the unresolved X-ray background predict that Compton-...
Context. Obscured AGN are fundamental to understand the history of supermassive black hole growth an...
We present X-ray spectral analysis of the brightest sources ($f_{2{-}10~{\rm keV}} > 10^{-15}$ $\rm...
Using mid-infrared and radio selection criteria, we pre-select a sample of candidate high-redshift t...
Using mid-infrared and radio selection criteria, we pre-select a sample of candidate high-redshift t...
Using mid-infrared and radio criteria, we select a sample of candidate z~2 obscured quasars. Optical...
This thesis presents a study of high-redshift obscured (type-2) quasars, selected at mid-infrared an...
The intrinsic column density (N-H) distribution of quasars is poorly known. At the high obscuration ...
We present new mid-infrared and submillimetre observations for a sample of eight high redshift type-...
XMM-Newton observations of 29 high redshift (z>2) quasars, including seven radio-quiet, 16 radio-lou...
Quasars with extremely red infrared-to-optical colours are an interesting population that can test i...
Using the large multiwavelength data set in the Chandra/SWIRE Survey (0.6 deg2 in the Lockman Hole),...
Quasars may have played a key role in limiting the stellar mass of massive galaxies. Identifying tho...
Using the large multiwavelength data set in the Chandra/SWIRE Survey (0.6 deg2 in the Lockman Hole),...
Obscured quasars hidden in deep X-ray surveys can be recovered by looking at mid-infrared wavelength...
Many models that seek to explain the origin of the unresolved X-ray background predict that Compton-...
Context. Obscured AGN are fundamental to understand the history of supermassive black hole growth an...
We present X-ray spectral analysis of the brightest sources ($f_{2{-}10~{\rm keV}} > 10^{-15}$ $\rm...