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X-ray spectral constraints for z~2 massive galaxies : the identification of reflection-dominated active galactic nuclei. Authors:Alexander reporter:王文侠. Outline. Introduction Data and stacking procedures Analyses and results Summary. Introduction.
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X-ray spectral constraints for z~2 massive galaxies: the identification of reflection-dominated active galactic nuclei Authors:Alexander reporter:王文侠
Outline • Introduction • Data and stacking procedures • Analyses and results • Summary
Introduction • Employ X-ray stacking analyses of X-ray undetected IR galaxies • X-ray stacking analyses need to be treated with caution • Extend the analyses of Daddi et al.
Data and stacking procedures • Galaxy sample 76 objects classified as IR-excess and 146 objects classified as IR-normal galaxies
X-Ray matching 47 BzK galaxies have an X-ray counterpart,28 of which are classified as IR-excess galaxies and 19 of which are classified as IR-normal galaxies •X-ray variability
Analyses and results • X-ray detected BzK Galaxies
Classification of the X-ray emission 11 of the 47 X-ray detected BzK galaxies are classified as "heavily obscured AGNs" 9 of these objects are classified as "luminous AGNs",the other 27 objects are classified as "low-luminosity X-ray systems"
Re-evaluation of the space density of distant compton-thick AGNs
Summary • The overall X-ray spectra of the heavily obscured AGNs are better characterized by a pure reflection model than an absorbed power-law model • many of the heavily obscured AGNs are IR-excess galaxies • X-ray stacking analyses of the X-ray undetected BzK galaxies do not clearly reveal the presence of further X-ray undectected AGNs • Estimate a compton-thick AGN space density