2014AJ....147....6M

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. This 3σ limit corresponds to a rest-frame 1.4 GHz luminosity density limit of L_ν, 1.4 GHz_< 1.76x10²⁴ W/Hz for a spectral index of α = 0, and L_ν, 1.4 GHz_< 1.42x10²⁵ W/Hz for a spectral index of α = -1. The rest-frame 1.4 GHz luminosity limits are L_rad< 6.43x10⁶ L_☉ and L_rad< 5.20x10⁷ L_☉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_1.4^* < 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 that this quasar is radio-quiet and located at the low end of the radio-quiet distribution of high-redshift (z ≳ 6) quasars.