How Are Red and Blue Quasars Different? The Radio Properties

Fawcett, Victoria A.; Alexander, David M.; Rosario, David J.; Klindt, Lizelke

Abstract

A non-negligible fraction of quasars are red at optical wavelengths, indicating (in the majority of cases) that the accretion disc is obscured by a column of dust which extinguishes the shorter-wavelength blue emission. In this paper, we summarize recent work by our group, where we find fundamental differences in the radio properties of SDSS optically-selected red quasars. We also present new analyses, using a consistent color-selected quasar parent sample matched to four radio surveys (FIRST, VLA Stripe 82, VLA COSMOS 3 GHz, and LoTSS DR1) across a frequency range 144 MHz–3 GHz and four orders of magnitude in radio flux. We show that red quasars have enhanced small-scale radio emission (∼kpc) that peaks around the radio-quiet threshold (defined as the ratio of 1.4 GHz luminosity to 6 μm luminosity) across the four radio samples. Exploring the potential mechanisms behind this enhancement, we rule out star-formation and propose either small-scale synchrotron jets, frustrated jets, or dusty winds interacting with the interstellar medium; the latter two scenarios would provide a more direct connection between opacity (dust; gas) and the production of the radio emission. In our future study, using new multi-band uGMRT data, we aim to robustly distinguish between these scenarios.

Citation

Fawcett, V. A., Alexander, D. M., Rosario, D. J., & Klindt, L. (2021). How Are Red and Blue Quasars Different? The Radio Properties. Galaxies, 9(4), Article 107. https://doi.org/10.3390/galaxies9040107

• Journal Article Type: Article
• Acceptance Date: Nov 16, 2021
• Online Publication Date: Nov 19, 2021
• Publication Date: 2021
• Deposit Date: Dec 8, 2021
• Publicly Available Date: Dec 8, 2021
• Journal: Galaxies
• Electronic ISSN: 2075-4434
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 4
• Article Number: 107
• DOI: https://doi.org/10.3390/galaxies9040107
• Public URL: https://durham-repository.worktribe.com/output/1219832