A New Radio-X-Ray Probe of Galaxy Cluster Magnetic Fields

By T. Clarke, P. Kronberg, H. Böhringer. 2000

429 citations recorded by the source corpus.

Results are presented of a new VLA-ROSAT study that probes the magnetic field strength and distribution over a sample of 16 "normal" low-redshift (z ≤ 0.1) galaxy clusters. The clusters span 2 orders of magnitude in X-ray luminosity and were selected to be free of (unusual) strong radio cluster halos and widespread cooling flows. Consistent with these criteria, most clusters show a relaxed X-ray morphology and little or no evidence of recent merger activity. Analysis of the rotation measure (RM) data shows cluster-generated Faraday RM excess out to ~0.5 h Mpc from cluster centers. The results, combined with RM imaging of cluster-embedded sources and ROSAT X-ray profiles, indicate that the hot intergalactic gas within these "normal" clusters is permeated with a high filling factor by magnetic fields at levels of icm = 5-10(ℓ/10 kpc)-1/2 h μG, where ℓ is the field correlation length. These results lead to a global estimate of the total magnetic energy in clusters and give new insight into the ultimate energy origin, which is likely gravitational. These results also shed some light on the cluster evolutionary conditions that existed at the onset of cooling flows.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/ff8f19abf67ac958905bce6f51bf32017ef87c3c

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Citations in the corpus

Magnetic fields and Faraday rotation in clusters of galaxies (2004, result): “From a statistical study of several clusters, Clarke et al. (2001) obtained magnetic fields of 4−8 µG, in agreement with the above findings.”
The Coma cluster magnetic field from Faraday rotation measures (2009, background): “…against this interpretation: – the trend of RM versus the cluster impact parameter in both statistical studies and individual cluster investigations (Clarke et al. 2001, 2004; Feretti et al. 1999; Govoni et al. 2005); – the Laing-Garrington effect (Laing 1988, Garrington et al. 1988, Garrington &…”
Cosmological Magnetic Fields: Their Generation, Evolution and Observation (2013, background): “Similar limits can also be derived from the absence of non-Gaussianities in the observed CMB anisotropies.”
An improved map of the Galactic Faraday sky (2011, neutral): “Clarke et al. (2001) estimated the cluster contribution by comparing the RM values of sources within the cluster to those of sources behind the cluster.”
Generation of large scale magnetic fields in single-field inflation (2007, background): “Furthermore, in recent years, magnetic fields in clusters of galaxies have been observed by means of the Faraday rotation measurements (RMs) of polarized electromagnetic radiation passing through an ionized medium [6, 7, 8 ]. Unfortunately, however, RMs give only the product of the field strength a”
Inflationary magnetogenesis without the strong coupling problem (2013, background): “While the typical field strength in galaxies and clusters is of the order of a few micro-Gauss [4], a careful study of some astrophysical processes seems to suggest a lower bound of a few femto-Gauss on the coherent magnetic fields in the intergalactic medium [5](for some recent reviews, see also [6”
Astrophysical magnetic fields and nonlinear dynamo theory (2004, background): “A very 33 interesting statistical study in this context is a recent VLA survey [139], where the RMs in and behind a sample of 16 Abell clusters were determined.”