The X-ray to optical-UV luminosity ratio of X-ray selected type 1 AGN in XMM-COSMOS
Creators
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Lusso, E.1
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Comastri, A.
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Vignali, C.1
- Zamorani, G.
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Brusa, M.2
- Gilli, R.
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Iwasawa, K.
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Salvato, M.3
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Civano, F.4
- Elvis, M.4
- Merloni, A.2, 5
- Bongiorno, A.2
- Trump, J. R.6
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Koekemoer, A. M.7
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Schinnerer, E.8
- Le Floc'h, E.9
- Cappelluti, N.2
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Jahnke, K.8
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Sargent, M. T.10
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Silverman, J.10
- Mainieri, V.2, 11
- Fiore, F.12
- Bolzonella, M.
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Le Fèvre, O.13
- Garilli, B.
- Iovino, A.14
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Kneib, J. P.13
- Lamareille, F.
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Lilly, S.10
- Mignoli, M.
- Scodeggio, M.
- Vergani, D.1
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1.
University of Bologna
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2.
Max Planck Society
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3.
California Institute of Technology
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4.
Harvard-Smithsonian Center for Astrophysics
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5.
Excellence Cluster Universe
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6.
University of Arizona
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7.
Space Telescope Science Institute
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8.
Max Planck Institute for Astronomy
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9.
University of Hawaii at Manoa
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10.
ETH Zurich
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11.
European Southern Observatory
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12.
Astronomical Observatory of Rome
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13.
Laboratoire d'Astrophysique de Marseille
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14.
Brera Astronomical Observatory
Abstract
We present a study of the X-ray to optical properties of a sample of 545 X-ray selected type 1 AGN, from the XMM-COSMOS survey, over a wide range of redshifts (0.04 < z < 4.25) and X-ray luminosities (40.6 ≤ Log L_([2-10] keV) ≤ 45.3). About 60% of them are spectroscopically identified type 1 AGN, while the others have a reliable photometric redshift and are classified as type 1 AGN on the basis of their multi-band Spectral Energy Distributions. We discuss the relationship between UV and X-ray luminosity, as parameterized by the α_(ox) spectral slope, and its dependence on redshift and luminosity. We compare our findings with previous investigations of optically selected broad-line AGN (mostly from SDSS). A highly significant correlation between α_(ox) and L_(2500 Å) is found, in agreement with previous investigations of optically selected samples. We calculate bolometric corrections, k_(bol), for the whole sample using hard X-ray luminosities (L_([2-10] keV)), and the Eddington ratios for a subsample of 150 objects for which black hole mass estimates are available. We confirm the trend of increasing bolometric correction with increasing Eddington ratio as proposed in previous works. A tight correlation is found between α_(ox) and k_(bol), which can be used to estimate accurate bolometric corrections using only optical and X-ray data. We find a significant correlation between α_(ox) and Eddington ratio, in which the ratio between X-ray and optical flux decreases with increasing Eddington ratio.
Additional Information
© 2010 ESO. Received: 15 September 2009; accepted: 4 January 2010. In Italy, the XMM-COSMOS project is supported by PRIN/MIUR under grant 2006-02-5203, ASI-INAF grants I/023/05/00, I/088/06 and ASI/COFIS/WP3110 I/026/07/0. In Germany the XMM-Newton project is supported by the Bundesministerium für Wirtshaft und Techologie/Deutsches Zentrum für Luft und Raumfahrt and the Max-Planck society. The entire COSMOS collaboration is gratefully acknowledged.Attached Files
Published - Lusso2010p9928Astron_Astrophys.pdf
Files
Lusso2010p9928Astron_Astrophys.pdf
Additional details
Identifiers
- Eprint ID
- 18584
- Resolver ID
- CaltechAUTHORS:20100607-120917341
Related works
- Describes
- http://cdsarc.u-strasbg.fr/cgi-bin/qcat?J/A+A/512/A34 (URL)
Dates
- Created
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2010-06-07Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field
Caltech Custom Metadata
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)