The Chandra Multi-wavelength Project: Optical Spectroscopy and the Broadband Spectral Energy Distributions of X-Ray-selected AGNs.
Author
Trichas, Markos
Green, Paul J.
Silverman, John D.
Aldcroft, Tom
Barkhouse, Wayne
Cameron, Robert A.
Constantin, Anca
Ellison, Sara L.
Foltz, Craig
Haggard, Daryl
Jannuzi, Buell T.
Marshall, Herman L.
Pérez, Laura M.
Romero-Colmenero, Encarni
Ruiz, Angel
Smith, Malcolm G.
Smith, Paul S.
Wik, Daniel R.
Wolfgang, Angie
Note: Order does not necessarily reflect citation order of authors.
Published Version
https://doi.org/10.1088/0067-0049/200/2/17Metadata
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Trichas, Markos, Paul J. Green, John D. Silverman, Tom Aldcroft, Wayne Barkhouse, Robert A. Cameron, Anca Constantin, et al. 2012. “The Chandra Multi-wavelength Project: Optical Spectroscopy and the Broadband Spectral Energy Distributions of X-Ray-selected AGNs.” The Astrophysical Journal Supplement Series 200 (2) (May 30): 17. doi:10.1088/0067-0049/200/2/17.Abstract
From optical spectroscopy of X-ray sources observed as part of ChaMP, we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic follow up using the FLWO, SAAO, WIYN, CTIO, KPNO, Magellan, MMT and Gemini telescopes, and from archival SDSS spectroscopy. We classify the optical counterparts as 50% BLAGN, 16% NELG, 14% ALG, and 20% stars. We detect QSOs out to z~5.5 and galaxies out to z~3. We have compiled extensive photometry from X-ray to radio bands. Together with our spectroscopic information, this enables us to derive detailed SEDs for our extragalactic sources. We fit a variety of templates to determine bolometric luminosities, and to constrain AGN and starburst components where both are present. While ~58% of X-ray Seyferts require a starburst event to fit observed photometry only 26% of the X-ray QSO population appear to have some kind of star formation contribution. This is significantly lower than for the Seyferts, especially if we take into account torus contamination at z>1 where the majority of our X-ray QSOs lie. In addition, we observe a rapid drop of the percentage of starburst contribution as X-ray luminosity increases. This is consistent with the quenching of star formation by powerful QSOs, as predicted by the merger model, or with a time lag between the peak of star formation and QSO activity. We have tested the hypothesis that there should be a strong connection between X-ray obscuration and star-formation but we do not find any association between X-ray column density and star formation rate both in the general population or the star-forming X-ray Seyferts. Our large compilation also allows us to report here the identification of 81 XBONG, 78 z>3 X-ray sources and 8 Type-2 QSO candidates. Also we have identified the highest redshift (z=5.4135) X-ray selected QSO with optical spectroscopy.Other Sources
https://arxiv.org/abs/1204.5148Terms of Use
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