Radiation-pressure Waves and Multiphase Quasar Outflows
- Creators
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Mas-Ribas, Lluís
Abstract
We report on quasar outflow properties revealed by analyzing more than 60 composite outflow spectra built from ~60,000 C iv absorption troughs in the SDSS-III/BOSS DR12QBAL catalog. We assess the dependences of the equivalent widths of many outflow metal absorption features on outflow velocity, trough width and position, and quasar magnitude and redshift. The evolution of the equivalent widths of the O vi and N v lines with outflow velocity correlates with that of the mean absorption-line width, the outflow electron density, and the strength of lines arising from collisionally excited metastable states. None of these correlations are found for the other high- or low-ionization species, and different behaviors with trough width are also suggested. We find no dependence on quasar magnitude or redshift in any case. All the observed trends can be reconciled by considering a multiphase stratified outflow structure, where inner regions are colder, denser, and host lower-ionization species. Given the prevalence of radiative acceleration in quasar outflows found by Mas-Ribas & Mauland, we suggest that radiation pressure sweeps up and compresses the outflowing gas outward, creating waves or filaments where the multiphase stratified structure could take form. This scenario is supported by the suggested correlation between electron density and outflow velocity, as well as by the similar behavior observed for the line and line-locking components of the absorption features. We show that this outflow structure is also consistent with other X-ray, radiative transfer, and polarization results, and discuss the implications of our findings for future observational and numerical quasar outflow studies.
Additional Information
© 2019 The American Astronomical Society. Received 2019 January 18; revised 2019 August 25; accepted 2019 August 30; published 2019 November 1. I thank the referee for an in-depth and constructive revision of the manuscript that has improved the presentation and analysis of the results. The initial inspiration for this work grew out of a stimulating discussion with Paul Martini during a visit supported by the Visitor Program at the Ohio State Center for Cosmology and Astroparticle Physics. I am grateful to him for valuable ideas and comments on this manuscript, and to the CCAP for kind hospitality. Thanks also to Renate Mauland for her work on the spectral stacks in this and our previous paper, and for several revisions of this manuscript. I am thankful to Ski Antonucci for enriching and valuable discussions on polarization in outflows, to Tzu-Ching Chang, Robert Wissing, Phil Berger, Sijing Shen, and Joop Schaye for conversations on shocks, waves and the outflow structure, and to Max Gronke for discussions on gas hydrodynamics. Thanks to Daniel Proga for a careful review of this manuscript and for providing many great comments, suggestions, and references, and to Stan Owocki for sharing his thoughts and notes on hydrostatic cloud modeling. I am grateful to Suoqing Ji, Fred Hamann, Sterl Phinney, Nick Scoville, Eliot Quataeret, Tom Barlow, and other colleagues at JPL and Caltech for many interesting comments and discussions. I am also thankful to the UCSB/MPIA ENIGMA group, for their kind hospitality and comments. This research was partially carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. 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 website 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.Attached Files
Published - Mas-Ribas_2019_ApJ_885_95.pdf
Accepted Version - 1903.08170.pdf
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Additional details
- Eprint ID
- 99611
- Resolver ID
- CaltechAUTHORS:20191101-091451340
- NASA/JPL/Caltech
- Alfred P. Sloan Foundation
- Participating Institutions
- NSF
- Department of Energy (DOE)
- Created
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2019-11-01Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field