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Title: The highest redshift quasar at z = 7.085: A radio-quiet source

We present 1-2 GHz Very Large Array A-configuration continuum observations on the highest redshift quasar known to date, the z = 7.085 quasar ULAS J112001.48+064124.3. The results show no radio continuum emission at the optical position of the quasar or its vicinity at a level of ≥3σ or 23.1 μJy beam{sup –1}. This 3σ limit corresponds to a rest-frame 1.4 GHz luminosity density limit of L {sub ν,} {sub 1.4} {sub GHz} < 1.76 × 10{sup 24} W Hz{sup –1} for a spectral index of α = 0, and L {sub ν,} {sub 1.4} {sub GHz} < 1.42 × 10{sup 25} W Hz{sup –1} for a spectral index of α = –1. The rest-frame 1.4 GHz luminosity limits are L {sub rad} < 6.43 × 10{sup 6} L {sub ☉} and L {sub rad} < 5.20 × 10{sup 7} L {sub ☉} for α = 0 and α = –1, respectively. The derived limits for the ratio of the rest-frame 1.4 GHz luminosity density to the B-band optical luminosity density are R{sub 1.4}{sup ∗}<0.53 and <4.30 for the above noted spectral indices, respectively. Given our upper limits on the radio continuum emission and the radio-to-optical luminosity ratio, we conclude thatmore » this quasar is radio-quiet and located at the low end of the radio-quiet distribution of high-redshift (z ≳ 6) quasars.« less
Authors:
;  [1] ; ;  [2]
  1. National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States)
  2. Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)
Publication Date:
OSTI Identifier:
22340049
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 147; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BEAMS; CONFIGURATION; DENSITY; DISTRIBUTION; EMISSION; GALAXIES; GHZ RANGE; LUMINOSITY; QUASARS; RED SHIFT