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Ultraviolet Fe II emission in fainter quasars: luminosity dependences, and the influence of environments

Clowes, Roger G. and Haberzettl, Lutz and Raghunathan, Srinivasan and Williger, Gerard M. and Mitchell, Sophia M. and Söchting, Ilona K. and Graham, Matthew J. and Campusano, Luis E. (2016) Ultraviolet Fe II emission in fainter quasars: luminosity dependences, and the influence of environments. Monthly Notices of the Royal Astronomical Society, 460 (2). pp. 1428-1444. ISSN 0035-8711.

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We investigate the strength of ultraviolet Fe ii emission in fainter quasars compared with brighter quasars for 1.0 ≤ z ≤ 1.8, using the Sloan Digital Sky Survey (SDSS) DR7QSO catalogue and spectra of Schneider et al., and the SDSS Faint Quasar Survey (SFQS) catalogue and spectra of Jiang et al. We quantify the strength of the UV Fe ii emission using the W2400 equivalent width of Weymann et al., which is defined between two rest-frame continuum windows at 2240–2255 and 2665–2695 Å. The main results are the following. (1) We find that for W2400 ≳ 25 Å there is a universal (i.e. for quasars in general) strengthening of W2400 with decreasing intrinsic luminosity, L3000. (2) In conjunction with previous work by Clowes et al., we find that there is a further, differential, strengthening of W2400 with decreasing L3000 for those quasars that are members of Large Quasar Groups (LQGs). (3) We find that increasingly strong W2400 tends to be associated with decreasing full width at half maximum (FWHM) of the neighbouring Mg ii λ2798 broad emission line. (4) We suggest that the dependence of W2400 on L3000 arises from Lyα fluorescence. (5) We find that stronger W2400 tends to be associated with smaller virial estimates from Shen et al. of the mass of the central black hole, by a factor of ∼2 between the ultrastrong emitters and the weak. Stronger W2400 emission would correspond to smaller black holes that are still growing. The differential effect for LQG members might then arise from preferentially younger quasars in the LQG environments.

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URLURL TypeDescription Paper
Raghunathan, Srinivasan0000-0003-1405-378X
Graham, Matthew J.0000-0002-3168-0139
Additional Information:© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 April 28. Received 2016 April 27; in original form 2015 August 31. First published online May 1, 2016. We wish to thank Linhua Jiang for providing us with the SFQS spectra in digital form and Martin Gaskell for very informative discussions on the characteristics of the BLRs in quasars. The anonymous referee is thanked for a thoughtful and constructive review of the paper. We also wish to thank the R Foundation for Statistical Computing for the r software. LEC received partial support from the Center of Excellence in Astrophysics and Associated Technologies (PFB 06), and from a CONICYT Anillo project (ACT 1122). SR was in receipt of a CONICYT PhD studentship while much of this work was in progress. This research has used the SDSS DR7QSO catalogue (Schneider et al. 2010). Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web Site is The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington.
Funding AgencyGrant Number
Center of Excellence in Astrophysics and Associated TechnologiesPFB 06
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)ACT 1122
Alfred P. Sloan FoundationUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Japanese MonbukagakushoUNSPECIFIED
Max Planck SocietyUNSPECIFIED
Higher Education Funding Council for EnglandUNSPECIFIED
Subject Keywords:galaxies: active galaxies: clusters: general quasars: emission lines large-scale structure of Universe
Issue or Number:2
Record Number:CaltechAUTHORS:20160909-134904899
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Official Citation:Roger G. Clowes, Lutz Haberzettl, Srinivasan Raghunathan, Gerard M. Williger, Sophia M. Mitchell, Ilona K. Söchting, Matthew J. Graham, and Luis E. Campusano Ultraviolet Fe ii emission in fainter quasars: luminosity dependences, and the influence of environments MNRAS (August 01, 2016) Vol. 460 1428-1444 doi:10.1093/mnras/stw1021 first published online May 1, 2016
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:70253
Deposited By: Ruth Sustaita
Deposited On:09 Sep 2016 23:57
Last Modified:09 Mar 2020 13:19

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