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Title: The intrinsic quasar luminosity function: Accounting for accretion disk anisotropy

Abstract

Quasar luminosity functions are a fundamental probe of the growth and evolution of supermassive black holes. Measuring the intrinsic luminosity function is difficult in practice, due to a multitude of observational and systematic effects. As sample sizes increase and measurement errors drop, characterizing the systematic effects is becoming more important. It is well known that the continuum emission from the accretion disk of quasars is anisotropic—in part due to its disk-like structure—but current luminosity function calculations effectively assume isotropy over the range of unobscured lines of sight. Here, we provide the first steps in characterizing the effect of random quasar orientations and simple models of anisotropy on observed luminosity functions. We find that the effect of orientation is not insignificant and exceeds other potential corrections such as those from gravitational lensing of foreground structures. We argue that current observational constraints may overestimate the intrinsic luminosity function by as much as a factor of ∼2 on the bright end. This has implications for models of quasars and their role in the universe, such as quasars' contribution to cosmological backgrounds.

Authors:
; ;  [1];  [2];  [3]
  1. University of Wyoming, Department of Physics and Astronomy 3905, 1000 East University, Laramie, WY 82071 (United States)
  2. Penn State University, Department of Astronomy and Astrophysics, 413 Davey Lab, University Park, PA 16802 (United States)
  3. Large Binocular Telescope Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
Publication Date:
OSTI Identifier:
22356838
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCOUNTING; ACCRETION DISKS; ANISOTROPY; BLACK HOLES; CORRECTIONS; EMISSION; EVOLUTION; GALAXIES; GRAVITATIONAL LENSES; ISOTROPY; LIMITING VALUES; LUMINOSITY; MASS; QUASARS; RANDOMNESS; UNIVERSE

Citation Formats

DiPompeo, M. A., Myers, A. D., Brotherton, M. S., Runnoe, J. C., and Green, R. F. The intrinsic quasar luminosity function: Accounting for accretion disk anisotropy. United States: N. p., 2014. Web. doi:10.1088/0004-637X/787/1/73.
DiPompeo, M. A., Myers, A. D., Brotherton, M. S., Runnoe, J. C., & Green, R. F. The intrinsic quasar luminosity function: Accounting for accretion disk anisotropy. United States. doi:10.1088/0004-637X/787/1/73.
DiPompeo, M. A., Myers, A. D., Brotherton, M. S., Runnoe, J. C., and Green, R. F. Tue . "The intrinsic quasar luminosity function: Accounting for accretion disk anisotropy". United States. doi:10.1088/0004-637X/787/1/73.
@article{osti_22356838,
title = {The intrinsic quasar luminosity function: Accounting for accretion disk anisotropy},
author = {DiPompeo, M. A. and Myers, A. D. and Brotherton, M. S. and Runnoe, J. C. and Green, R. F.},
abstractNote = {Quasar luminosity functions are a fundamental probe of the growth and evolution of supermassive black holes. Measuring the intrinsic luminosity function is difficult in practice, due to a multitude of observational and systematic effects. As sample sizes increase and measurement errors drop, characterizing the systematic effects is becoming more important. It is well known that the continuum emission from the accretion disk of quasars is anisotropic—in part due to its disk-like structure—but current luminosity function calculations effectively assume isotropy over the range of unobscured lines of sight. Here, we provide the first steps in characterizing the effect of random quasar orientations and simple models of anisotropy on observed luminosity functions. We find that the effect of orientation is not insignificant and exceeds other potential corrections such as those from gravitational lensing of foreground structures. We argue that current observational constraints may overestimate the intrinsic luminosity function by as much as a factor of ∼2 on the bright end. This has implications for models of quasars and their role in the universe, such as quasars' contribution to cosmological backgrounds.},
doi = {10.1088/0004-637X/787/1/73},
journal = {Astrophysical Journal},
number = 1,
volume = 787,
place = {United States},
year = {Tue May 20 00:00:00 EDT 2014},
month = {Tue May 20 00:00:00 EDT 2014}
}
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