Fundamental differences in the properties of red and blue quasars: measuring the reddening and accretion properties with X-shooter
Abstract
We have recently found fundamental differences in the radio properties of red quasars when compared to typical blue quasars. In this paper, we use data from the X-shooter spectrograph on the Very Large Telescope, providing spectral coverage from ∼3000–$25\,000\,$ Å, of a sample of 40 red and blue luminous quasars at 1.45 < z < 1.65 to explore the connections between the radio, emission-line, and accretion-disc properties. We fit various dust-extinction curves to the data and find that dust reddening can fully explain the observed colours for the majority of the red quasars in our sample, with moderate extinctions ranging from AV ∼ 0.06–0.7 mag. We confront our spectra with a simple thin accretion-disc model and find this can describe the continua of both the blue and red quasars, once corrected for dust extinction; we also find no significant differences in the accretion properties. We detect ionized outflows in a number of red and blue quasars, but do not find any significant evidence that they are more prevalent in the red quasar population. Overall our findings imply that the radio emission is more closely connected to circumnuclear/ISM opacity rather than accretion disc or outflow differences.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 13, 2022
- Source ID
- 10.1093/mnras/stac945
Entities
People
- David M. Alexander
- David Rosario
- Elisabeta Lusso
- Gabriela Calistro Rivera
- Leah Morabito
- Lizelke Klindt
- V. A. Fawcett
Organizations
- ACVO Vision for Animals Foundation
- Alfred P. Sloan Foundation
- American Museum of Natural History
- Arcetri Observatory
- California Institute of Technology
- Case Western Reserve University
- Chinese Academy of Sciences
- Drexel University
- Durham University
- European Southern Observatory
- Higher Education Funding Council for England
- Institute for Advanced Study
- Jet Propulsion Laboratory
- Johns Hopkins University
- Los Alamos National Laboratory
- Maritime and Port Authority of Singapore
- Medical Research Council
- National Aeronautics and Space Administration
- National Science Foundation
- New Mexico State University
- Newcastle University
- Ohio State University
- Princeton University
- Science and Technology Facilities Council
- United States Department of Energy
- United States Naval Observatory
- University of Basel
- University of California
- University of Cambridge
- University of Chicago
- University of Florence
- University of Pittsburgh
- University of Portsmouth
- University of Washington