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The Faint End of the QSO Luminosity Function at z = 3

Hunt, Matthew P. and Steidel, Charles C. and Adelberger, Kurt L. and Shapley, Alice E. (2004) The Faint End of the QSO Luminosity Function at z = 3. Astrophysical Journal, 605 (2). pp. 625-630. ISSN 0004-637X. doi:10.1086/381727.

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We present the first measurement of the faint end of the QSO luminosity function at z = 3. The QSOs, which range from M_(1450) = -21 to M_(1450) = -27, were discovered in 17 fields totaling 0.43 deg^2 using multicolor selection criteria (the Lyman break technique) and spectroscopic follow-up. We find that the faint-end slope of the luminosity function is β_l = 1.24 ± 0.07 (Φ ∝ L^(-β_t)), flatter than the value of β_l = 1.64 ± 0.18 measured at lower redshift. The integrated rest 1450 Å UV luminosity of z = 3 QSOs is only 50% of most previous estimates and only sime8% of that produced by Lyman break galaxies at the same redshifts. Assuming that ionizing photons from faint QSOs are as successful in escaping their host galaxies as bright QSOs, we estimate the total contribution of QSOs to the ionizing flux J912 at z ~ 3, J912 ≃ 2.4 × 10^(-22) ergs s^(-1) cm^(-2) Hz^(-1). This estimate, which we regard as an upper limit, remains consistent with rough estimates of J_(912) based on the Lyα forest "proximity effect."

Item Type:Article
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URLURL TypeDescription Paper
Steidel, Charles C.0000-0002-4834-7260
Shapley, Alice E.0000-0003-3509-4855
Additional Information:© 2004. The American Astronomical Society. Received 2003 September 16; accepted 2003 December 1. We wish to extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. Without their generous hospitality, most of the observations presented herein would not have been possible. We would also like to thank the staffs at the Keck and Palomar observatories for their invaluable assistance with the observations, and the anonymous referee for helpful suggestions. M. P. H., C. C. S., and A. E. S. have been supported by grant AST 00-70773 from the US National Science Foundation and by the David and Lucile Packard Foundation. Based, in part, on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
NSFAST 00-70773
Issue or Number:2
Record Number:CaltechAUTHORS:20170408-154715902
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Official Citation:Matthew P. Hunt et al 2004 ApJ 605 625
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76067
Deposited By: 1Science Import
Deposited On:23 May 2017 20:32
Last Modified:15 Nov 2021 16:57

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