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

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. Here, 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 flattensmore » 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.« less
ORCiD logo [1] ; ORCiD logo [2] ;  [1] ; ORCiD logo [1] ;  [1] ;  [3] ;  [4] ;  [4] ; ORCiD logo [5] ; ORCiD logo [6] ;  [7] ;  [1] ;  [8] ; ORCiD logo [9] ;  [10] ;  [1] ;  [11] ;  [12] ; ORCiD logo [13] ; ORCiD logo [14] more »;  [15] ;  [16] ; ORCiD logo [1] ;  [17] ; ORCiD logo [18] ; ORCiD logo [1] ; ORCiD logo [17] « less
  1. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
  2. Stanford Univ., CA (United States). Dept. of Physics
  3. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Univ. of Southampton (United Kingdom). Dept. of Physics and Astronomy
  4. Univ. of Hamburg (Germany). Hamburger Sternwarte
  5. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Kavli Inst. for Astrophysics and Space Research
  6. Naval Research Lab. (NRL), Washington, DC (United States)
  7. Max Planck Inst. for Astrophysics, Garching (Germany); Space Research Inst., Moscow (Russia)
  8. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  9. Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy
  10. Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences
  11. National Radio Astronomy Observatory, Charlottesville, VA (United States)
  12. Univ. of Oxford (United Kingdom). Dept. of Physics
  13. European Organization for Astronomical Research in the Southern Hemisphere (ESO), Munchen (Germany)
  14. Harvard-Smithsonian Center for Astrophysics, Crawley WA (United States). International Centre for Radio Astronomy Research (ICRAR)
  15. Univ. degli Studi di Ferrara (Italy). Dipartimento di Fisica e Scienze della Terra
  16. Univ. of Hull, Cottinton Road, Hall (United States)
  17. California Inst. of Technology (CalTech), Pasadena, CA (United States). Cahill Center for Astronomy and Astrophysics
  18. Academia Sinica, Taipei (Taiwan). Inst. of Astronomy and Astrophysics
Publication Date:
Report Number(s):
Journal ID: ISSN 1538-4357
Grant/Contract Number:
AC52-07NA27344; NAS8-03060; NAS5-26555; GO3-14131X; HSTHF2-51334.001-A; 12065.007-A
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 835; Journal Issue: 2; Journal ID: ISSN 1538-4357
Institute of Physics (IOP)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE; National Aeronautic and Space Administration (NASA)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; galaxies: clusters: individual (MACS J0717.5+3745); galaxies: clusters: intracluster medium; radiation mechanisms: non-thermal; X-rays: galaxies: clusters
OSTI Identifier: