Millimeter and Radio Observations of z ~ 6 Quasars - Archive ouverte HAL
Article Dans Une Revue The Astronomical Journal Année : 2007

Millimeter and Radio Observations of z ~ 6 Quasars

Ran Wang
Chris L. Carilli
  • Fonction : Auteur
Alexandre Beelen
  • Fonction : Auteur
Frank Bertoldi
Xiaohui Fan
Fabian Walter
Karl M. Menten
  • Fonction : Auteur
Pierre Cox
  • Fonction : Auteur
Michael A. Strauss
  • Fonction : Auteur
Linhua Jiang
  • Fonction : Auteur

Résumé

We present millimeter and radio observations of 13 SDSS quasars at redshifts z~6. We observed 11 of them with the Max Planck Millimeter Bolometer Array (MAMBO-2) at the IRAM 30 m telescope at 250 GHz and all of them with the Very Large Array (VLA) at 1.4 GHz. Four sources are detected by MAMBO-2 and six are detected by the VLA at the >~3 σ level. These sources, together with another six published in previous papers, yield a submillimeter/millimeter- and radio-observed SDSS quasar sample at z~6. We use this sample to investigate the far-infrared (FIR) and radio properties of optically bright quasars in the early universe. We compare this sample to lower redshift samples of quasars observed in the submillimeter and millimeter wavelengths [(sub)mm] and find that the distribution of the FIR-to-B-band optical luminosity ratio (LFIR/LB) is similar from z~2 to 6. We find a weak correlation between the FIR luminosity (LFIR) and B-band optical luminosity (LB) by including the (sub)mm observed samples at all redshifts. Some strong (sub)mm detections in the z~6 sample have radio-to-FIR ratios within the range defined by star-forming galaxies, which suggests possible coeval star-forming activity with the powerful AGN in these sources. We calculate the rest-frame radio-to-optical ratios (R*1.4=Lν,1.4GHz/Lν,4400Å) for all of the VLA-observed sources in the z~6 quasar sample. Only one radio detection in this sample, J083643.85+005453.3, has R*1.4~40 and can be considered radio-loud. There are no strong radio sources (R*1.4>=100) among these SDSS quasars at z~6. These data are consistent with, although do not set strong constraints on, a decreasing radio-loud quasar fraction with increasing redshift.

Dates et versions

hal-03646579 , version 1 (19-04-2022)

Identifiants

Citer

Ran Wang, Chris L. Carilli, Alexandre Beelen, Frank Bertoldi, Xiaohui Fan, et al.. Millimeter and Radio Observations of z ~ 6 Quasars. The Astronomical Journal, 2007, 134, pp.617-627. ⟨10.1086/518867⟩. ⟨hal-03646579⟩
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