Radio continuum imaging of far-infrared-luminous QSOs at z > 6

C. L. Carilli, F. Walter, F. Bertoldi, K. M. Menten, Xiaohui Fan, G. F. Lewis, Michael A. Strauss, Pierre Cox, A. Beelen, A. Omont, N. Mohan

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Abstract

We present sensitive imaging at 1.4 GHz of the two highest redshift far-infrared (FIR) luminous QSOs, SDSS J114816.65+525150.2 (z = 6.42) and SDSS J104845.05+463718.3 (z = 6.2). Radio continuum emission is detected from J1148+5251 with S1.4 = 55 ± 12 μJy, while J1048+4637 is marginally detected with S1.4 = 26 ± 12 μJy. Comparison of the radio and FIR luminosities shows that both sources follow the radio-FIR correlation for star-forming galaxies, with implied (massive) star formation rates ∼103 M yr-1, although we cannot rule out as much as 50% of the FIR luminosity being powered by the active galactic nucleus. Five bright (>22 mJy) radio sources are detected within 8′ of J1148+5251. This is a factor of 30 more than expected for a random field. Two sources have SDSS redshifts, including a z = 1.633 radio-loud quasar and a z = 0.05 radio galaxy. However, we do not find evidence for a galaxy cluster in the SDSS data, at least out to z = 0.2. Considering the faint SDSS magnitudes of the remaining radio sources, we conclude that the overdensity of radio sources could either be a statistical fluke or a very large scale structure (>8 Mpc comoving) at z ≥ 1. We also consider the possibility of gravitational lensing by the closest (in angle) bright galaxy in the SDSS data at z = 0.05 and conclude that the galaxy provides negligible magnification.

Original languageEnglish (US)
Pages (from-to)997-1001
Number of pages5
JournalAstronomical Journal
Volume128
Issue number3 1785
DOIs
StatePublished - Sep 2004

Fingerprint

quasars
radio
galaxies
continuums
luminosity
radio galaxies
star formation rate
magnification
massive stars
active galactic nuclei
stars

Keywords

  • Galaxies: active
  • Galaxies: formation
  • Galaxies: high-redshift
  • Galaxies: starburst
  • Infrared: galaxies
  • Radio continuum: galaxies

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Carilli, C. L., Walter, F., Bertoldi, F., Menten, K. M., Fan, X., Lewis, G. F., ... Mohan, N. (2004). Radio continuum imaging of far-infrared-luminous QSOs at z > 6. Astronomical Journal, 128(3 1785), 997-1001. https://doi.org/10.1086/423295

Radio continuum imaging of far-infrared-luminous QSOs at z > 6. / Carilli, C. L.; Walter, F.; Bertoldi, F.; Menten, K. M.; Fan, Xiaohui; Lewis, G. F.; Strauss, Michael A.; Cox, Pierre; Beelen, A.; Omont, A.; Mohan, N.

In: Astronomical Journal, Vol. 128, No. 3 1785, 09.2004, p. 997-1001.

Research output: Contribution to journalArticle

Carilli, CL, Walter, F, Bertoldi, F, Menten, KM, Fan, X, Lewis, GF, Strauss, MA, Cox, P, Beelen, A, Omont, A & Mohan, N 2004, 'Radio continuum imaging of far-infrared-luminous QSOs at z > 6', Astronomical Journal, vol. 128, no. 3 1785, pp. 997-1001. https://doi.org/10.1086/423295
Carilli CL, Walter F, Bertoldi F, Menten KM, Fan X, Lewis GF et al. Radio continuum imaging of far-infrared-luminous QSOs at z > 6. Astronomical Journal. 2004 Sep;128(3 1785):997-1001. https://doi.org/10.1086/423295
Carilli, C. L. ; Walter, F. ; Bertoldi, F. ; Menten, K. M. ; Fan, Xiaohui ; Lewis, G. F. ; Strauss, Michael A. ; Cox, Pierre ; Beelen, A. ; Omont, A. ; Mohan, N. / Radio continuum imaging of far-infrared-luminous QSOs at z > 6. In: Astronomical Journal. 2004 ; Vol. 128, No. 3 1785. pp. 997-1001.
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abstract = "We present sensitive imaging at 1.4 GHz of the two highest redshift far-infrared (FIR) luminous QSOs, SDSS J114816.65+525150.2 (z = 6.42) and SDSS J104845.05+463718.3 (z = 6.2). Radio continuum emission is detected from J1148+5251 with S1.4 = 55 ± 12 μJy, while J1048+4637 is marginally detected with S1.4 = 26 ± 12 μJy. Comparison of the radio and FIR luminosities shows that both sources follow the radio-FIR correlation for star-forming galaxies, with implied (massive) star formation rates ∼103 M⊙ yr-1, although we cannot rule out as much as 50{\%} of the FIR luminosity being powered by the active galactic nucleus. Five bright (>22 mJy) radio sources are detected within 8′ of J1148+5251. This is a factor of 30 more than expected for a random field. Two sources have SDSS redshifts, including a z = 1.633 radio-loud quasar and a z = 0.05 radio galaxy. However, we do not find evidence for a galaxy cluster in the SDSS data, at least out to z = 0.2. Considering the faint SDSS magnitudes of the remaining radio sources, we conclude that the overdensity of radio sources could either be a statistical fluke or a very large scale structure (>8 Mpc comoving) at z ≥ 1. We also consider the possibility of gravitational lensing by the closest (in angle) bright galaxy in the SDSS data at z = 0.05 and conclude that the galaxy provides negligible magnification.",
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AU - Carilli, C. L.

AU - Walter, F.

AU - Bertoldi, F.

AU - Menten, K. M.

AU - Fan, Xiaohui

AU - Lewis, G. F.

AU - Strauss, Michael A.

AU - Cox, Pierre

AU - Beelen, A.

AU - Omont, A.

AU - Mohan, N.

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N2 - We present sensitive imaging at 1.4 GHz of the two highest redshift far-infrared (FIR) luminous QSOs, SDSS J114816.65+525150.2 (z = 6.42) and SDSS J104845.05+463718.3 (z = 6.2). Radio continuum emission is detected from J1148+5251 with S1.4 = 55 ± 12 μJy, while J1048+4637 is marginally detected with S1.4 = 26 ± 12 μJy. Comparison of the radio and FIR luminosities shows that both sources follow the radio-FIR correlation for star-forming galaxies, with implied (massive) star formation rates ∼103 M⊙ yr-1, although we cannot rule out as much as 50% of the FIR luminosity being powered by the active galactic nucleus. Five bright (>22 mJy) radio sources are detected within 8′ of J1148+5251. This is a factor of 30 more than expected for a random field. Two sources have SDSS redshifts, including a z = 1.633 radio-loud quasar and a z = 0.05 radio galaxy. However, we do not find evidence for a galaxy cluster in the SDSS data, at least out to z = 0.2. Considering the faint SDSS magnitudes of the remaining radio sources, we conclude that the overdensity of radio sources could either be a statistical fluke or a very large scale structure (>8 Mpc comoving) at z ≥ 1. We also consider the possibility of gravitational lensing by the closest (in angle) bright galaxy in the SDSS data at z = 0.05 and conclude that the galaxy provides negligible magnification.

AB - We present sensitive imaging at 1.4 GHz of the two highest redshift far-infrared (FIR) luminous QSOs, SDSS J114816.65+525150.2 (z = 6.42) and SDSS J104845.05+463718.3 (z = 6.2). Radio continuum emission is detected from J1148+5251 with S1.4 = 55 ± 12 μJy, while J1048+4637 is marginally detected with S1.4 = 26 ± 12 μJy. Comparison of the radio and FIR luminosities shows that both sources follow the radio-FIR correlation for star-forming galaxies, with implied (massive) star formation rates ∼103 M⊙ yr-1, although we cannot rule out as much as 50% of the FIR luminosity being powered by the active galactic nucleus. Five bright (>22 mJy) radio sources are detected within 8′ of J1148+5251. This is a factor of 30 more than expected for a random field. Two sources have SDSS redshifts, including a z = 1.633 radio-loud quasar and a z = 0.05 radio galaxy. However, we do not find evidence for a galaxy cluster in the SDSS data, at least out to z = 0.2. Considering the faint SDSS magnitudes of the remaining radio sources, we conclude that the overdensity of radio sources could either be a statistical fluke or a very large scale structure (>8 Mpc comoving) at z ≥ 1. We also consider the possibility of gravitational lensing by the closest (in angle) bright galaxy in the SDSS data at z = 0.05 and conclude that the galaxy provides negligible magnification.

KW - Galaxies: active

KW - Galaxies: formation

KW - Galaxies: high-redshift

KW - Galaxies: starburst

KW - Infrared: galaxies

KW - Radio continuum: galaxies

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