TY - JOUR
T1 - The Faint End of the z = 5 Quasar Luminosity Function from the CFHTLS
AU - McGreer, Ian D.
AU - Fan, Xiaohui
AU - Jiang, Linhua
AU - Cai, Zheng
N1 - Funding Information:
I. D. McGreer and X. Fan acknowledge the support from the U.S. NSF grant AST 15-15115. L.J. acknowledges support from the National Key R&D Program of China (2016YFA0400703) and from the National Science Foundation of China (grant 11533001). The work presented here is based in part on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia).
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved.
PY - 2018/3
Y1 - 2018/3
N2 - We present results from a spectroscopic survey of z ∼ 5 quasars in the CFHT Legacy Survey. Using both optical color selection and a likelihood method, we select 97 candidates over an area of 105 deg2 to a limit of i AB < 23.2, and 7 candidates in the range 23.2 < i AB < 23.7 over an area of 18.5 deg2. Spectroscopic observations for 43 candidates were obtained with Gemini, MMT, and Large Binocular Telescope, of which 37 are z > 4 quasars. This sample extends measurements of the quasar luminosity function ∼1.5 mag fainter than our previous work in Sloan Digital Sky Survey Stripe 82. The resulting luminosity function is in good agreement with our previous results, and suggests that the faint end slope is not steep. We perform a detailed examination of our survey completeness, particularly the impact of the Lyα emission assumed in our quasar spectral models, and find hints that the observed Lyα emission from faint z ∼ 5 quasars is weaker than for z ∼ 3 quasars at a similar luminosity. Our results strongly disfavor a significant contribution of faint quasars to the hydrogen-ionizing background at z = 5.
AB - We present results from a spectroscopic survey of z ∼ 5 quasars in the CFHT Legacy Survey. Using both optical color selection and a likelihood method, we select 97 candidates over an area of 105 deg2 to a limit of i AB < 23.2, and 7 candidates in the range 23.2 < i AB < 23.7 over an area of 18.5 deg2. Spectroscopic observations for 43 candidates were obtained with Gemini, MMT, and Large Binocular Telescope, of which 37 are z > 4 quasars. This sample extends measurements of the quasar luminosity function ∼1.5 mag fainter than our previous work in Sloan Digital Sky Survey Stripe 82. The resulting luminosity function is in good agreement with our previous results, and suggests that the faint end slope is not steep. We perform a detailed examination of our survey completeness, particularly the impact of the Lyα emission assumed in our quasar spectral models, and find hints that the observed Lyα emission from faint z ∼ 5 quasars is weaker than for z ∼ 3 quasars at a similar luminosity. Our results strongly disfavor a significant contribution of faint quasars to the hydrogen-ionizing background at z = 5.
KW - galaxies: high redshift
KW - quasars: emission lines
KW - quasars: general
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U2 - 10.3847/1538-3881/aaaab4
DO - 10.3847/1538-3881/aaaab4
M3 - Article
AN - SCOPUS:85043597888
VL - 155
JO - Astronomical Journal
JF - Astronomical Journal
SN - 0004-6256
IS - 3
M1 - 131
ER -