Relighting the fire in Hickson Compact Group (HCG) 15: magnetised fossil plasma revealed by the SKA Pathfinders & Precursors

Abstract

In the context of the life cycle and evolution of active galactic nuclei (AGN), the environment plays an important role. In particular, the over-dense environments of galaxy groups, where dynamical interactions and bulk motions have significant impact, offer an excellent but under-explored window into the life cycles of AGN and the processes that shape the evolution of relativistic plasma. Pilot Survey observations with the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) survey recovered diffuse emission associated with the nearby (z = 0.0228) galaxy group HCG15, which was revealed to be strongly linearly polarised. We study the properties of this emission in unprecedented detail to settle open questions about its nature and its relation to the group-member galaxies. We perform a multi-frequency spectropolarimetric study of HCG15 incorporating our ASKAP EMU observations as well as new data from MeerKAT, LOFAR, the GMRT, and the Karl G. Jansky Very Large Array (VLA), plus X-ray data from XMM-Newton and optical spectra from the Himalayan Chandra Telescope (HCT). Our study confirms that the diffuse structure represents remnant emission from historic AGN activity, likely associated with HCG15-D, some 80-86 Myr ago (based on ageing analysis). We detect significant highly linearly-polarised emission from a diffuse 'ridge'-like structure with a highly ordered magnetic field. Our analysis suggests that this emission is generated by draping of magnetic field lines in the intra-group medium (IGrM), although further exploration with simulations would aid our understanding. We confirm that HCG15-C is a group-member galaxy. Finally, we report the detection of thermal emission associated with a background cluster at redshift z ~ 0.87 projected onto the IGrM of HCG15, which matches the position and redshift of the recent SZ detection of ACT-CL J0207.8+0209.

Accepted for publication in A&A. Manuscript is 35 pages, contains 19 figures. Abstract abridged due to arXiv's requirements

References in corpus (76)

• Array Programming with NumPy
• The NumPy array: a structure for efficient numerical computation
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release
• The LOFAR Two-metre Sky Survey -- V. Second data release
• Diffuse Radio Emission from Galaxy Clusters
• Revised equipartition & minimum energy formula for magnetic field strength estimates from radio synchrotron observations
• The eROSITA Final Equatorial Depth Survey (eFEDS): The X-ray catalog
• CMasher: Scientific colormaps for making accessible, informative and 'cmashing' plots
• An optimized algorithm for multi-scale wideband deconvolution of radio astronomical images
• The Dark Energy Survey Data Release 2
• Australian Square Kilometre Array Pathfinder: I. System Description
• The Rapid ASKAP Continuum Survey I: Design and First Results
• Strangulation in Galaxy Groups
• Full spectrum fitting with photometry in pPXF: stellar population versus dynamical masses, non-parametric star formation history and metallicity for 3200 LEGA-C galaxies at redshift z~0.8
• Scaling Properties of a Complete X-ray Selected Galaxy Group Sample
• Science With The Australian Square Kilometre Array Pathfinder
• Draping of Cluster Magnetic Fields over Bullets and Bubbles -- Morphology and Dynamic Effects
• The LOFAR Two Meter Sky Survey: Deep Fields, I -- Direction-dependent calibration and imaging
• Radio interferometric gain calibration as a complex optimization problem
• The Rapid ASKAP Continuum Survey Paper II: First Stokes I Source Catalogue Data Release
• LOFAR/H-ATLAS: The low-frequency radio luminosity - star-formation rate relation
• LOFAR/H-ATLAS: A deep low-frequency survey of the Herschel-ATLAS North Galactic Pole field
• LOFAR observations of galaxy clusters in HETDEX
• Non-linear Kalman filters for calibration in radio interferometry
• Feedback from Active Galactic Nuclei in Galaxy Groups
• Impact of tangled magnetic fields on AGN-blown bubbles
• The 1.28 GHz MeerKAT DEEP2 Image
• A radio spectral index map and catalogue at 147-1400 MHz covering 80 per cent of the sky
• The Australian Square Kilometre Array Pathfinder: System Architecture and Specifications of the Boolardy Engineering Test Array
• Galaxy Evolution in Hickson Compact Groups: The Role of Ram Pressure Stripping and Strangulation
• All-purpose, all-sky photometric redshifts for the Legacy Imaging Surveys Data Release 8
• Simulating Groups and the IntraGroup Medium: The Surprisingly Complex and Rich Middle Ground Between Clusters and Galaxies
• The Australian Square Kilometre Array Pathfinder: Performance of the Boolardy Engineering Test Array
• Intragroup diffuse light in compact groups of galaxies II. HCG 15, 35 and 51
• A snapshot of the oldest AGN feedback phases
• MeerKAT uncovers the physics of an Odd Radio Circle
• Discovery of a new extragalactic circular radio source with ASKAP: ORC J0102-2450
• The Spectral Variability of the GHz-Peaked Spectrum Radio Source PKS 1718-649 and a Comparison of Absorption Models
• Radio spectral properties and jet duty cycle in the restarted radio galaxy 3C388
• The galaxy group NGC 507: newly detected AGN remnant plasma transported by sloshing
• Early Science from POSSUM: Shocks, turbulence, and a massive new reservoir of ionised gas in the Fornax cluster
• Target Selection for the DESI Peculiar Velocity Survey
• Deep low-frequency radio observations of Abell 2256 I: The filamentary radio relic
• Constraining the AGN duty cycle in the cool-core cluster MS 0735.6+7421 with LOFAR data
• Radio fossils, relics, and haloes in Abell 3266: cluster archaeology with ASKAP-EMU and the ATCA
• Understanding the radio relic emission in the galaxy cluster MACS J0717.5+3745: spectral analysis
• Spectral ageing in the era of big data: integrated vs resolved models
• A MeerKAT-meets-LOFAR Study of MS 1455.0+2232: A 590 kiloparsec 'Mini'-Halo in a Sloshing Cool-Core Cluster
• Remnant Radio Galaxies Discovered in a Multi-frequency Survey
• Disturbed, diffuse, or just missing? A global study of the HI content of Hickson Compact Groups
• Spectral Variability of Radio Sources at Low Frequencies
• Multi-frequency characterisation of remnant radio galaxies in the Lockman Hole field
• Early Science with the Karoo Array Telescope: a Mini-Halo Candidate in Galaxy Cluster Abell 3667
• Turbulent magnetic fields in the merging galaxy cluster MACS J0717.5+3745: polarization analysis
• Radio relics radio emission from multi-shock scenario
• CHEX-MATE: Characterization of the intra-cluster medium temperature distribution
• MeerKAT Holography Measurements in the UHF, L, and S bands
• A MeerKAT-meets-LOFAR study of Abell 1413: a moderately disturbed non-cool-core cluster hosting a $\sim 500$ kpc 'mini'-halo
• Exploring diffuse radio emission in galaxy clusters and groups with the uGMRT and the SKA
• The MeerKAT Fornax Survey IV. A close look at the cluster physics through the densest rotation measure grid
• Polarised structures in the radio lobes of B2 0258+35 - Evidence of magnetic draping?
• X-ray luminosity-star formation rate scaling relation: Constraints from the eROSITA Final Equatorial Depth Survey (eFEDS)
• Wide-Band Spectral Variability of Peaked Spectrum Sources
• Evolution of the pc-scale structure of PKS 1934-638 revisited: first science with the ASKAP and New Zealand telescopes
• Selecting and Modelling Remnant AGNs with Limited Spectral Coverage
• The ACT-DR5 MCMF Galaxy Cluster Catalog
• Anomalous gas in ESO 149-G003: A MeerKAT-16 View
• A deep dive: Chandra observations of the NGC 4839 group falling into the Coma cluster
• Galaxy and Mass Assembly (GAMA): the clustering of galaxy groups
• New filamentary remnant radio emission and duty cycle constraints in the radio galaxy NGC 6086
• A MeerKAT Polarization Survey of Southern Calibration Sources
• A search for extended radio emission from selected compact galaxy groups
• Somewhere in between: Tracing the Radio Emission from Galaxy Groups (or Why Does the Future of Observing Galaxy Groups with Radio Telescopes Look Promising?)