The Spiderweb proto-cluster is being magnetized by its central radio jet

Abstract

We present deep broadband radio polarization observations of the Spiderweb radio galaxy (J1140-2629) in a galaxy proto-cluster at $z=2.16$. These yield the most detailed polarimetric maps yet made of a high redshift radio galaxy. The intrinsic polarization angles and Faraday Rotation Measures (RMs) reveal coherent magnetic fields spanning the $\sim 60$ kpc length of the jets, while $\sim 50$% fractional polarizations indicate these fields are well-ordered. Source-frame absolute RM values of $\sim 1,000$ rad/m/m are typical, and values up to $\sim 11,100$ rad/m/m are observed. The Faraday-rotating gas cannot be well-mixed with the synchrotron-emitting gas, or stronger-than-observed depolarization would occur. Nevertheless, an observed spatial coincidence between a localized absolute RM enhancement of $\sim 1,100$ rad/m/m, a bright knot of Ly$\alpha$ emission, and a deviation of the radio jet provide direct evidence for vigorous jet-gas interaction. We detect a large-scale RM gradient totaling $\sim 1,000$s rad/m/m across the width of the jet, suggesting a net clockwise (as viewed from the AGN) toroidal magnetic field component exists at 10s-of-kpc-scales, which we speculate may be associated with the operation of a Poynting-Robertson cosmic battery. We conclude the RMs are mainly generated in a sheath of hot gas around the radio jet, rather than the ambient foreground proto-cluster gas. The estimated magnetic field strength decreases by successive orders-of-magnitude going from the jet hotspots ($\sim 90$ $\mu$G) to the jet sheath ($\sim 10$ $\mu$G) to the ambient intracluster medium ($\sim 1$ $\mu$G). Synthesizing our results, we propose that the Spiderweb radio galaxy is actively magnetizing its surrounding proto-cluster environment, with possible implications for theories of the origin and evolution of cosmic magnetic fields.

12 pages, 7 figures, 2 tables. Accepted for publication in ApJ

References in corpus (26)

• Cosmic Star Formation History
• Simulating galaxy formation with black hole driven thermal and kinetic feedback
• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
• Distant Radio Galaxies and their Environments
• Fermi Gamma-ray Imaging of a Radio Galaxy
• MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments. VIII. Faraday rotation in parsec-scale AGN jets
• Star-Forming Galaxies at Cosmic Noon
• A radio ridge connecting two galaxy clusters in a filament of the cosmic web
• Minkowski's Object: A Starburst Triggered by a Radio Jet, Revisited
• The Spiderweb galaxy: a forming massive cluster galaxy at z~2
• The Evolution of the Baryons Associated with Galaxies Averaged over Cosmic Time and Space
• The Detection of a Red Sequence of Massive Field Galaxies at z~2.3 and its Evolution to z~0
• High-energy Particle Acceleration and Production of Ultra-high-energy Cosmic Rays in the Giant Lobes of Centaurus A
• Why z > 1 radio-loud galaxies are commonly located in proto-clusters
• Molecular Gas in the Halo Fuels the Growth of a Massive Cluster Galaxy at High Redshift
• ALMA observations of massive molecular gas filaments encasing radio bubbles in the Phoenix cluster
• The 700 ks Chandra Spiderweb Field I: evidence for widespread nuclear activity in the Protocluster
• Metal enriched gaseous halos around distant radio galaxies: Clues to feedback in galaxy formation
• Simulating the transport of relativistic electrons and magnetic fields injected by radio galaxies in the intracluster medium
• Early Science from POSSUM: Shocks, turbulence, and a massive new reservoir of ionised gas in the Fornax cluster
• Magnetization of the intergalactic medium in the IllustrisTNG simulations: the importance of extended, outflow-driven bubbles
• Characterizing the Uncertainty in Cluster Magnetic Fields derived from Rotation Measures
• Molecular gas along the old radio jets of the cluster-central type 2 quasar IRAS 09104+4109
• Proof of CMB-driven X-ray brightening of high-z radio galaxies
• X-ray Emission and Radio Emission from the Jets and Lobes of the Spiderweb Radio Galaxy

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• COALAS III: The ATCA CO(1-0) look at the growth and death of H$\alpha$ emitters in the Spiderweb protocluster at z=2.16
• CO survey of high-z radio galaxies, revisited with ALMA: Jet-cloud Alignments and Synchrotron Brightening by Molecular Gas in the Circumgalactic Environment
• JWST + ALMA ubiquitously discover companion systems within $\lesssim 18$kpc around four $z$$\approx$3.5 luminous radio-loud AGN
• Magnetic dynamos in galaxy clusters: the crucial role of galaxy formation physics at high redshifts
• AGN feedback in an infant galaxy cluster: the LOFAR-Chandra view of the giant FRII radio galaxy J103025+052430 at z=1.7
• Numerical modelling of the lobes of radio galaxies VI. Polarimetric simulations of universal pressure profile cluster atmospheres