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- Title
Radio relics tracing the projected mass distribution in CIZA J2242.8+5301.
- Authors
Nobuhiro OKABE; Hiroki AKAMATSU; Jun KAKUWA; Yutaka FUJITA; Yuying ZHANG; Masayuki TANAKA; Keiichi UMETSU
- Abstract
We present a weak-lensing analysis for a merging galaxy cluster, CIZA J2242.8+5301, which hosts double radio relics, using three-band Subaru/Suprime-Cam imaging (Br'z'). Since the lifetime of dark matter halos colliding into clusters is longer than that of X-ray emitting gas halos, weak-lensing analysis is a powerful method to constrain merger dynamics. Two-dimensional shear fitting using a clean background catalog suggests that the cluster undergoes a merger with a mass ratio of about 2: 1. The main halo is located around the gas core in the southern region, while no concentrated gas core is associated with the northern sub-halo. We find that the projected cluster mass distribution resulting from an unequal-mass merger is in excellent agreement with the curved shapes of the two radio relics and the overall X-ray morphology, except for the lack of the northern gas core. The lack of a prominent radio halo enables us to constrain an upper limit of the fractional energy of magnetohydrodynamic turbulence of (δB/B)2 < O(10−6) at a resonant wavenumber, by finding a balance between the acceleration time and the time after the core passage or the cooling time, with an assumption of resonant acceleration by a second-order Fermi process.
- Subjects
RADIO sources (Astronomy); STELLAR mass; GALAXY clusters; DARK matter; HALOS (Meteorology); GRAVITATIONAL lenses; X-rays
- Publication
Publications of the Astronomical Society of Japan, 2015, Vol 67, Issue 6, p1
- ISSN
0004-6264
- Publication type
Article
- DOI
10.1093/pasj/psv085