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A catalogue of optical to X-ray spectral energy distributions of z ≈ 2 quasars observed with Swift – I. First results

A catalogue of optical to X-ray spectral energy distributions of z ≈ 2 quasars observed with Swift – I. First results
A catalogue of optical to X-ray spectral energy distributions of z ≈ 2 quasars observed with Swift – I. First results
We present the Swift optical to X-ray spectral energy distributions (SEDs) of 44 quasars at redshifts z ≈ 2 observed by Swift, part of a larger program to establish and characterize the optical through X-ray SEDs of moderate-redshift quasars. Here, we outline our analysis approach and present preliminary analysis and results for the first third of the full quasar sample. Not all quasars in the sample are detected in X-rays; all of the X-ray-detected objects so far are radio loud. As expected for radio-loud objects, they are X-ray bright relative to radio-quiet quasars of comparable optical luminosities, with an average αox =1.39 ± 0.03 (where αox is the power-law slope connecting the monochromatic flux at 2500 Å and at 2 keV), and display hard X-ray spectra. We find integrated 3000 Å–25 keV accretion luminosities of between 0.7 × 1046 erg s−1 and 5.2 × 1047 erg s−1. Based on single-epoch spectroscopic virial black hole mass estimates, we find that these quasars are accreting at substantial Eddington fractions, 0.1 L/LEdd 1.
Catalogues – quasars: general
1365-2966
4674-46710
Lawther, D.
e49b26ad-3d71-4699-9e8a-647278a792f7
Vestergaard, M.
0403f403-5b3b-4cc4-b3f0-87f841afe909
Raimundo, S.
e409d9d3-17e8-4049-ad29-43ada60b24e2
Grupe, D.
c5c55483-6653-4a69-805d-1a4c6c49c2bc
Lawther, D.
e49b26ad-3d71-4699-9e8a-647278a792f7
Vestergaard, M.
0403f403-5b3b-4cc4-b3f0-87f841afe909
Raimundo, S.
e409d9d3-17e8-4049-ad29-43ada60b24e2
Grupe, D.
c5c55483-6653-4a69-805d-1a4c6c49c2bc

Lawther, D., Vestergaard, M., Raimundo, S. and Grupe, D. (2017) A catalogue of optical to X-ray spectral energy distributions of z ≈ 2 quasars observed with Swift – I. First results. Monthly Notices Of The Royal Astronomical Society, 467 (4), 4674-46710. (doi:10.1093/mnras/stx423).

Record type: Article

Abstract

We present the Swift optical to X-ray spectral energy distributions (SEDs) of 44 quasars at redshifts z ≈ 2 observed by Swift, part of a larger program to establish and characterize the optical through X-ray SEDs of moderate-redshift quasars. Here, we outline our analysis approach and present preliminary analysis and results for the first third of the full quasar sample. Not all quasars in the sample are detected in X-rays; all of the X-ray-detected objects so far are radio loud. As expected for radio-loud objects, they are X-ray bright relative to radio-quiet quasars of comparable optical luminosities, with an average αox =1.39 ± 0.03 (where αox is the power-law slope connecting the monochromatic flux at 2500 Å and at 2 keV), and display hard X-ray spectra. We find integrated 3000 Å–25 keV accretion luminosities of between 0.7 × 1046 erg s−1 and 5.2 × 1047 erg s−1. Based on single-epoch spectroscopic virial black hole mass estimates, we find that these quasars are accreting at substantial Eddington fractions, 0.1 L/LEdd 1.

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More information

Accepted/In Press date: 16 February 2017
Published date: 1 June 2017
Additional Information: Funding Information: Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington and Yale University. Funding Information: We thank the anonymous referee for helpful feedback with regards to the X-ray modelling, and for a thorough report that improved the clarity of the manuscript as a whole. This work took advantage of the Danish Swift guaranteed time programme. We thank local Swift affiliate Daniele Malesani, and the Swift helpdesk at the University of Leicester, for their assistance in obtaining and processing the data. DL, MV and SR gratefully acknowledge support from the Danish Council for Independent Research via grant no. DFF 4002-00275. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington and Yale University. Funding Information: This work took advantage of the Danish Swift guaranteed time programme. We thank local Swift affiliate Daniele Malesani, and the Swift helpdesk at the University of Leicester, for their assistance in obtaining and processing the data. DL, MV and SR gratefully acknowledge support from the Danish Council for Independent Research via grant no. DFF 4002-00275. Publisher Copyright: © 2017 The Authors.
Keywords: Catalogues – quasars: general

Identifiers

Local EPrints ID: 473430
URI: http://eprints.soton.ac.uk/id/eprint/473430
ISSN: 1365-2966
PURE UUID: a71025d3-9227-4cc4-a133-122c2c00443f
ORCID for S. Raimundo: ORCID iD orcid.org/0000-0002-6248-398X

Catalogue record

Date deposited: 18 Jan 2023 17:31
Last modified: 18 Mar 2024 03:58

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Contributors

Author: D. Lawther
Author: M. Vestergaard
Author: S. Raimundo ORCID iD
Author: D. Grupe

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