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

Abstract

We present deep, multiwavelength radio observations of SpARCS104922.6+564032.5, a z = 1.71 galaxy cluster with a starbusting core. Observations were made with the Karl G. Jansky Very Large Array (JVLA) in 3 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\pm 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.

8 pages, 4 figures, MNRAS accepted

References in corpus (18)

• The hierarchical formation of the brightest cluster galaxies
• Heating Hot Atmospheres with Active Galactic Nuclei
• Shocks and cold fronts in galaxy clusters
• Star formation efficiency in galaxy interactions and mergers: a statistical study
• Turbulent Heating in Galaxy Clusters Brightest in X-rays
• The non-coplanar baselines effect in radio interferometry: The W-Projection algorithm
• An Infrared Survey of Brightest Cluster Galaxies. II: Why are Some Brightest Cluster Galaxies Forming Stars?
• Resurrecting the Red from the Dead: Optical Properties of BCGs in X-ray Luminous Clusters
• The VLA-COSMOS 3~GHz Large Project: Cosmic evolution of radio AGN and implications for radio-mode feedback since z~5
• ALMA observations of massive molecular gas filaments encasing radio bubbles in the Phoenix cluster
• Do sound waves transport the AGN energy in the Perseus Cluster?
• The Radio Continuum-Star Formation Rate Relation in WSRT SINGS Galaxies
• Near-infrared evolution of brightest cluster galaxies in the most X-ray luminous clusters since z=1
• Galaxy pairs in the Sloan Digital Sky Survey - XII: The fuelling mechanism of low excitation radio-loud AGN
• Smooth and Starburst Tidal Tails in the GEMS and GOODS Fields
• Detection of a Substantial Molecular Gas Reservoir in a brightest cluster galaxy at z = 1.7
• A distant radio mini-halo in the Phoenix galaxy cluster
• Infrared Emission from the Nearby Cool Core Cluster Abell 2597

Cited by in corpus (8)

• Molecular gas in CLASH brightest cluster galaxies at $z\sim 0.2-0.9$
• Evidence of runaway gas cooling in the absence of supermassive black hole feedback at the epoch of cluster formation
• Environmental processing in cluster core galaxies at z=1.7
• Constraining the Mass of the Emerging Galaxy Cluster SpARCS1049+56 at z=1.71 with Infrared Weak Lensing
• The H$\alpha$ star formation main sequence in cluster and field galaxies at $z\sim 1.6$
• An extreme case of galaxy and cluster co-evolution at $z$=0.7
• Euclid: A blue galaxy population and a brightest cluster galaxy in the making in a $z\sim 1.74$ MaDCoWS2 galaxy cluster candidate
• An Assessment of the In-Situ Growth of the Intracluster Light in the High Redshift Galaxy Cluster SpARCS1049+56