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Frontier fields clusters: Chandra and JVLA view of the pre-merging cluster MACS J0416.1-2403

Ogrean, G. A.; Weeren, R. J.Van; Jones, C.; Clarke, T. E.; Sayers, J.; Mroczkowski, T.; Nulsen, P. E. J.; Forman, W.; Murray, S. S.; Pandey-Pommier, M.; Randall, S.; Churazov, E.; Bonafede, A.; Kraft, R.; David, L.; Andrade-Santos, F.; Merten, J.; Zitrin, A.; Umetsu, K.; Goulding, A.; Roediger, E.; Bagchi, J.; Bulbul, E.; Donahue, M.; Ebeling, H.; Johnston-Hollitt, M.; Mason, B.; Rosati, P.; Vikhlinin, A.


G. A. Ogrean

R. J.Van Weeren

C. Jones

T. E. Clarke

J. Sayers

T. Mroczkowski

P. E. J. Nulsen

W. Forman

S. S. Murray

M. Pandey-Pommier

S. Randall

E. Churazov

A. Bonafede

R. Kraft

L. David

F. Andrade-Santos

J. Merten

A. Zitrin

K. Umetsu

A. Goulding

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Dr Elke Roediger
Senior Lecturer/ Director of Studies for Physics

J. Bagchi

E. Bulbul

M. Donahue

H. Ebeling

M. Johnston-Hollitt

B. Mason

P. Rosati

A. Vikhlinin


Merging galaxy clusters leave long-lasting signatures on the baryonic and non-baryonic cluster constituents, including shock fronts, cold fronts, X-ray substructure, radio halos, and offsets between the dark matter (DM) and the gas components. Using observations from Chandra, the Jansky Very Large Array, the Giant Metrewave Radio Telescope, and the Hubble Space Telescope, we present a multiwavelength analysis of the merging Frontier Fields cluster MACS J0416.1-2403 (z = 0.396), which consists of NE and SW subclusters whose cores are separated on the sky by ∼250 kpc. We find that the NE subcluster has a compact core and hosts an X-ray cavity, yet it is not a cool core. Approximately 450 kpc south-southwest of the SW subcluster, we detect a density discontinuity that corresponds to a compression factor of ∼1.5. The discontinuity was most likely caused by the interaction of the SW subcluster with a less massive structure detected in the lensing maps SW of the subcluster's center. For both the NE and the SW subclusters, the DM and the gas components are well-aligned, suggesting that MACS J0416.1-2403 is a pre-merging system. The cluster also hosts a radio halo, which is unusual for a pre-merging system. The halo has a 1.4 GHz power of (1.3 ±0.3) × 10 24 W Hz -1 , which is somewhat lower than expected based on the X-ray luminosity of the cluster if the spectrum of the halo is not ultra-steep. We suggest that we are either witnessing the birth of a radio halo, or have discovered a rare ultra-steep spectrum halo.


Ogrean, G. A., Weeren, R. J., Jones, C., Clarke, T. E., Sayers, J., Mroczkowski, T., …Vikhlinin, A. (2015). Frontier fields clusters: Chandra and JVLA view of the pre-merging cluster MACS J0416.1-2403. The Astrophysical journal, 812(2), 153. doi:10.1088/0004-637X/812/2/153

Journal Article Type Article
Acceptance Date Aug 31, 2015
Online Publication Date Oct 20, 2015
Publication Date Oct 20, 2015
Deposit Date Dec 6, 2017
Publicly Available Date Dec 6, 2017
Journal The Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 812
Issue 2
Pages 153
Keywords Space and Planetary Science; Astronomy and Astrophysics
Public URL


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