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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 710117.0, MPI für Astronomie / Publikationen_mpia
The highest redshift quasar at z = 7.085: A radio-quiet source
Authors:Momjian, E.; Carilli, C. L.; Walter, F.; Venemans, B.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:The Astronomical Journal
Issue / Number:1
Start Page:id. 6 (3 pp)
Audience:Not Specified
Abstract / Description: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 >=3sigma or 23.1 muJy beam-1. This 3sigma limit corresponds to a rest-frame 1.4 GHz luminosity density limit of L nu, 1.4 GHz < 1.76 × 1024 W Hz-1 for a spectral index of alpha = 0, and L nu, 1.4 GHz < 1.42 × 1025 W Hz-1 for a spectral index of alpha = -1. The rest-frame 1.4 GHz luminosity limits are L rad < 6.43 × 106 L &sun; and L rad < 5.20 × 107 L &sun; for alpha = 0 and alpha = -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.
Free Keywords:galaxies: active; galaxies: high-redshift; galaxies: individual: ULAS J112001.48+064124.3; radio continuum: galaxies; techniques: interferometric
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-6256 %R 10.1088/0004-6256/147/1/6
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