| Type |
Conference Paper |
| Names |
Laura Trouille, A. Barger, L. Cowie, R. Mushotzky, Y. Yang |
| Conference Name |
American Astronomical Society, AAS Meeting #215, #353.03 |
| Volume |
42 |
| Pages |
536 |
| Date |
January 1, 2010 |
| Short Title |
The OPTX Project |
| URL |
http://adsabs.harvard.edu/abs/2010AAS...21535303T |
| Library Catalog |
NASA ADS |
| Abstract |
In order to understand the evolution of Active Galactic Nuclei, it is
essential that we use a physically motivated classification scheme.
Using a uniformly selected and highly spectroscopically complete sample
of Chandra X-ray sources (the OPTX sample), we confirm that one cannot
use X-ray spectral classifications and optical spectral classifications
equivalently. We also show that there is not a one-to-one correspondence
between X-ray spectral type and the neutral hydrogen opacity of the
source. Until a better understanding is reached for how the X-ray and
optical classifications relate to the obscuration of the central engine,
the use of a mixed classification scheme can only complicate the
interpretation of X-ray AGN samples. On the basis of this study, we
advocate the adoption of a pure optical classification scheme for
studying AGN with low signal-to-noise X-ray spectra. However if high
quality X-ray spectra are available, they form an equally valid method
of categorizing the objects. We also compare the completeness in AGN
selection using X-ray versus optical emission line ratio diagnostic
diagrams. We confirm that we miss AGNs in our X-ray selected sample that
can be picked up by optical diagnostic diagrams. Conversely, there are
X-ray AGNs that lie in the star formation region of these diagrams that
we cannot find with this technique. We discuss the effect of this
incompleteness on the shape and evolution of X-ray and [OIII] AGN
luminosity functions.
L. Trouille gratefully acknowledges support from a National Science
Foundation Graduate Research Fellowship and a Wisconsin Space Grant
Consortium Graduate Fellowship Award while working on this Ph.D. thesis
work. |