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Environments of strong/ultrastrong, ultraviolet Fe II emitting quasars

Clowes, Roger G. and Raghunathan, Srinivasan and Söchting, Ilona K. and Graham, Matthew J. and Campusano, Luis E. (2013) Environments of strong/ultrastrong, ultraviolet Fe II emitting quasars. Monthly Notices of the Royal Astronomical Society, 433 (3). pp. 2467-2475. ISSN 0035-8711. doi:10.1093/mnras/stt915.

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We have investigated the strength of ultraviolet (UV) Fe ii emission from quasars within the environments of large quasar groups (LQGs) in comparison with quasars elsewhere, for 1.1 ≤ z_(LQG) ≤ 1.7, using the DR7QSO catalogue of the Sloan Digital Sky Survey. We use the Weymann et al. W2400 equivalent width, defined between the rest-frame continuum windows 2240–2255 and 2665–2695 Å, as the measure of the UV Fe ii emission. We find a significant shift of the W2400 distribution to higher values for quasars within LQGs, predominantly for those LQGs with 1.1 ≤ z_(LQG) ≤ 1.5. There is a tentative indication that the shift to higher values increases with the quasar i magnitude. We find evidence that within LQGs the ultrastrong emitters with W2400 ≥ 45 Å (more precisely, ultrastrong plus with W2400 ≥ 44 Å) have preferred nearest-neighbour separations of ∼30–50 Mpc to the adjacent quasar of any W2400 strength. No such effect is seen for the ultrastrong emitters that are not in LQGs. The possibilities for increasing the strength of the Fe ii emission appear to be iron abundance, Lyα fluorescence and microturbulence, and probably all of these operate. The dense environment of the LQGs may have led to an increased rate of star formation and an enhanced abundance of iron in the nuclei of galaxies. Similarly, the dense environment may have led to more active blackholes and increased Lyα fluorescence. The preferred nearest-neighbour separation for the stronger emitters would appear to suggest a dynamical component, such as microturbulence. In one particular LQG, the Huge-LQG (the largest structure known in the early Universe), six of the seven strongest emitters very obviously form three pairings within the total of 73 members.

Item Type:Article
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URLURL TypeDescription Paper
Raghunathan, Srinivasan0000-0003-1405-378X
Graham, Matthew J.0000-0002-3168-0139
Additional Information:© 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2013 May 22. Received 2013 May 17; in original form 2013 February 13. First published online: June 17, 2013. The anonymous referee is thanked for helpful comments and suggestions. 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 is in receipt of a CONICYT PhD studentship. 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 US 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 website 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
CONICYT Anillo projectACT 1122
Subject Keywords:galaxies: active; galaxies: clusters: general; quasars: emission lines; largescale structure of Universe.
Issue or Number:3
Record Number:CaltechAUTHORS:20130930-084406854
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Official Citation: Roger G. Clowes, Srinivasan Raghunathan, Ilona K. Söchting, Matthew J. Graham, and Luis E. Campusano Environments of strong/ultrastrong, ultraviolet Fe ii emitting quasars MNRAS (August 11, 2013) Vol. 433 2467-2475 first published online June 17, 2013 doi:10.1093/mnras/stt915
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41541
Deposited By: Ruth Sustaita
Deposited On:30 Sep 2013 16:29
Last Modified:10 Nov 2021 04:31

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