The NuSTAR and Chandra View of CL 0217+70 and Its Tell-tale Radio Halo

Journal
Date Issued
2023
Author(s)
Tümer, Ayşegül
•
Wik, Daniel R.
•
Zhang, Xiaoyuan
•
Hoang, Duy N.
•
•
van Weeren, Reinout J.
•
Rudnick, Lawrence
•
•
Mernier, François
•
Simionescu, Aurora
•
Rojas Bolivar, Randall A.
•
Kraft, Ralph
•
Akamatsu, Hiroki
•
de Plaa, Jelle
DOI
Description
We thank the anonymous referee for valuable suggestions that improved our manuscript. A.T. and D.R.W. acknowledge support from NASA NuSTAR GO grant No. 80NSSC22K0066 and from NASA ADAP award No. 80NSSC19K1443. M.G. acknowledges partial support by NASA Chandra GO9-20114X and HST GO-15890.020/023-A, and the BlackHoleWeather program. R.J.v.W. acknowledges support from the ERC Starting Grant ClusterWeb 804208. C.S. acknowledges support from the MIUR grant FARE “SMS”. A.T. thanks Ross Silver and Taweewat Somboonpanyakul for valuable discussions. This research has made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory (JPL), and funded by by the National Aeronautics and Space Administration (NASA). In this work, we used the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). The data for this research have been obtained from the High Energy Astrophysics Science Archive Research Center (HEASARC), provided by NASAs Goddard Space Flight Center. This research has also made use of data obtained from the Chandra Data Archive and the Chandra Source Catalog, and software provided by the Chandra X-ray Center (CXC) in the application package CIAO.
Abstract
Mergers of galaxy clusters are the most energetic events in the universe, driving shock and cold fronts, generating turbulence, and accelerating particles that create radio halos and relics. The galaxy cluster CL 0217+70 is a remarkable late-stage merger, with a double peripheral radio relic and a giant radio halo. Chandra detects surface brightness (SB) edges that correspond to radio features within the halo. In this work, we present a study of this cluster with Nuclear Spectroscopic Telescope Array and Chandra data using spectro-imaging methods. The global temperature is found to be kT = 9.1 keV. We set an upper limit for the inverse Compton (IC) flux of ~2.7 × 10-12 erg s-1 cm-2, and a lower limit to the magnetic field of 0.08 μG. Our local IC search revealed a possibility that IC emission may have a significant contribution at the outskirts of the radio halo emission and on/near shock regions within ~0.6 r 500 of clusters. We detected a "hot spot" feature in our temperature map coincident with an SB edge, but our investigation on its origin is inconclusive. If the "hot spot" is the downstream of a shock, we set a lower limit of kT > 21 keV to the plasma that corresponds to ${ \mathcal M }$ ~2. We found three shock fronts within 0.5 r 500. Multiple weak shocks within the cluster center hint at an ongoing merger activity and continued feeding of the giant radio halo. CL 0217+70 is the only example hosting these secondary shocks in multiple form.
Volume
942
Issue
79
Start page
1
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2023ApJ...942...79T
Rights
open.access
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