How are Red and Blue Quasars Different? The Radio Properties. (arXiv:2111.10384v2 [astro-ph.GA] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Fawcett_V/0/1/0/all/0/1">V. A. Fawcett</a> (CEA, Durham University), <a href="http://arxiv.org/find/astro-ph/1/au:+Alexander_D/0/1/0/all/0/1">D. M. Alexander</a> (CEA, Durham University), <a href="http://arxiv.org/find/astro-ph/1/au:+Rosario_D/0/1/0/all/0/1">D. J. Rosario</a> (Newcastle University, CEA, Durham University), <a href="http://arxiv.org/find/astro-ph/1/au:+Klindt_L/0/1/0/all/0/1">L. Klindt</a> (CEA, Durham University)
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 micron 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.
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 micron 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.
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