Multiwavelength radio observations of a brightest cluster galaxy at z = 1.71: Detection of a modest active galactic nucleus and evidence for extended star formation

Ariane Trudeau, Tracy Webb, Julie Hlavacek-Larrondo, Allison Noble, Marie Lou Gendron-Marsolais, Christopher Lidman, Mar Mezcua, Adam Muzzin, Gillian Wilson, H. K.C. Yee

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

We present deep, multiwavelength radio observations of SpARCS104922.6 + 564032.5, a z = 1.71 galaxy cluster with a starbursting core. Observations were made with the Karl G. Jansky Very Large Array (JVLA) in three bands: 1-2 GHz, 4-8 GHz, and 8-12 GHz. We detect a radio source coincident with the brightest cluster galaxy (BCG) that has a spectral index of α = 0.44 ± 0.29 and is indicative of emission from an active galactic nucleus. The radio luminosity is consistent with the average luminosity of the lower redshift BCG sample, but the flux densities are 6σ below the predicted values of the star-forming spectral energy distribution based on far infrared data. Our new fit fails to simultaneously describe the far infrared and radio fluxes. This, coupled with the fact that no other bright source is detected in the vicinity of the BCG implies that the star formation region, traced by the infrared emission, is extended or clumpy and not located directly within the BCG. Thus, we suggest that the star-forming core might not be driven by a single major wet merger, but rather by several smaller galaxies stripped of their gas or by a displaced cooling flow, although more data are needed to confirm any of those scenarios.

Original languageEnglish (US)
Pages (from-to)1210-1217
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume487
Issue number1
DOIs
StatePublished - Jul 21 2019

Keywords

  • Galaxies: Active
  • Galaxies: Clusters: Individual (SpARCS104922.6 + 564032.5)
  • Galaxies: Evolution
  • Galaxies: Interactions
  • Galaxies: Starburst
  • Radio continuum: Galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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