Chandra and JVLA Observations of HST Frontier Fields Cluster MACS J0717.5+3745

van Weeren, R. J.; Ogrean, G. A.; Jones, C.; Forman, W. R.; Andrade-Santos, F.; Pearce, Connor J. J.; Bonafede, A.; Brüggen, M.; Bulbul, E.; Clarke, T. E.; Churazov, E.; David, L.; Dawson, W. A.; Donahue, M.; Goulding, A.; Kraft, R. P.; Mason, B.; Merten, J.; Mroczkowski, T.; Nulsen, P. E. J.; Rosati, P.; Roediger, E.; Randall, S. W.; Sayers, J.; Umetsu, K.; Vikhlinin, A.; Zitrin, A.

Abstract

To investigate the relationship between thermal and non-thermal components in merger galaxy clusters, we present deep JVLA and Chandra observations of the HST Frontier Fields cluster MACS J0717.5+3745. The Chandra image shows a complex merger event, with at least four components belonging to different merging subclusters. Northwest of the cluster, ∼0.7 Mpc from the center, there is a ram-pressure-stripped core that appears to have traversed the densest parts of the cluster after entering the intracluster medium (ICM) from the direction of a galaxy filament to the southeast. We detect a density discontinuity north-northeast of this core, which we speculate is associated with a cold front. Our radio images reveal new details for the complex radio relic and radio halo in this cluster. In addition, we discover several new filamentary radio sources with sizes of 100-300 kpc. A few of these seem to be connected to the main radio relic, while others are either embedded within the radio halo or projected onto it. A narrow-angled-tailed (NAT) radio galaxy, a cluster member, is located at the center of the radio relic. The steep spectrum tails of this active galactic nucleus lead into the large radio relic where the radio spectrum flattens again. This morphological connection between the NAT radio galaxy and relic provides evidence for re-acceleration (revival) of fossil electrons. The presence of hot ≳20 keV ICM gas detected by Chandra near the relic location provides additional support for this re-acceleration scenario.

Citation

van Weeren, R. J., Ogrean, G. A., Jones, C., Forman, W. R., Andrade-Santos, F., Pearce, C. J. J., Bonafede, A., Brüggen, M., Bulbul, E., Clarke, T. E., Churazov, E., David, L., Dawson, W. A., Donahue, M., Goulding, A., Kraft, R. P., Mason, B., Merten, J., Mroczkowski, T., Nulsen, P. E. J., …Zitrin, A. (2017). Chandra and JVLA Observations of HST Frontier Fields Cluster MACS J0717.5+3745. The Astrophysical journal, 835(2), 197. https://doi.org/10.3847/1538-4357/835/2/197

• Journal Article Type: Article
• Acceptance Date: Dec 24, 2016
• Online Publication Date: Jan 31, 2017
• Publication Date: Jan 31, 2017
• Deposit Date: Apr 10, 2018
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 835
• Issue: 2
• Pages: 197
• DOI: https://doi.org/10.3847/1538-4357/835/2/197
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://hull-repository.worktribe.com/output/773690
• Contract Date: Apr 10, 2018