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Title: Multi-wavelength Observations of the Dissociative Merger in the Galaxy Cluster CIZA J0107.7+5408

We present results based on X-ray, optical, and radio observations of the massive galaxy cluster CIZA J0107.7+5408. We find that this system is a post-core-passage, dissociative, binary merger, with the optical galaxy density peaks of each subcluster leading their associated X-ray emission peaks. This separation occurs because the diffuse gas experiences ram pressure forces, while the effectively collisionless galaxies (and presumably their associated dark matter (DM) halos) do not. This system contains double-peaked diffuse radio emission, possibly a double radio relic with the relics lying along the merger axis and also leading the X-ray cores. We find evidence for a temperature peak associated with the SW relic, likely created by the same merger shock that is powering the relic radio emission in this region. Thus, this system is a relatively rare, clean example of a dissociative binary merger, which can in principle be used to place constraints on the self-interaction cross-section of DM. Low-frequency radio observations reveal ultra-steep spectrum diffuse radio emission that is not correlated with the X-ray, optical, or high-frequency radio emission. Here, we suggest that these sources are radio phoenixes, which are preexisting non-thermal particle populations that have been re-energized through adiabatic compression by the same mergermore » shocks that power the radio relics. Finally, we place upper limits on inverse Compton emission from the SW radio relic.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [1] ;  [3] ; ORCiD logo [4] ; ORCiD logo [2] ;  [5] ;  [6] ; ORCiD logo [7]
  1. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
  2. Naval Research Lab. (NRL), Washington, DC (United States)
  3. National Radio Astronomy Observatory, Socorro, NM (United States)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  5. Boston Univ., MA (United States). Astronomy Dept. and Inst. for Astrophysical Research
  6. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Kavli Inst. for Astrophysics & Space Research
  7. Univ. of Maryland, College Park, MD (United States). Dept. of Astronomy
Publication Date:
Report Number(s):
LLNL-JRNL-737794
Journal ID: ISSN 1538-4357
Grant/Contract Number:
AC52-07NA27344; GO3-14134X; NAS8-03060
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 823; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
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
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS
OSTI Identifier:
1430969