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ID 47046
file
creator
Sasaki, Toru
Matsushita, Kyoko
Sato, Kosuke
subject
galaxies: clusters: individual (Coma Cluster) – X-rays: galaxies: clusters
NDC
Astronomy. Space sciences
abstract
We observed three massive subhalos in the Coma cluster with Suzaku. These subhalos, labeled “ID 1,” “ID 2,” and “ID 32,” were detected with a weak-lensing survey using Subaru/Suprime-Cam, and are located at the projected distances of 1.4 r_500, 1.2 r_500, and 1.6 r_500 from the center of the Coma cluster, respectively. The subhalo “ID 1” has a compact X-ray excess emission close to the center of the weak-lensing mass contour, and the gas mass to weak-lensing mass ratio is about 0.001. The temperature of the emission is about 3 keV, which is slightly lower than that of the surrounding intracluster medium (ICM) and that expected for the temperature versus mass relation of clusters of galaxies. The subhalo “ID 32” shows an excess emission whose peak is shifted toward the opposite direction from the center of the Coma cluster. The gas mass to weak-lensing mass ratio is also about 0.001, which is significantly smaller than regular galaxy groups. The temperature of the excess is about 0.5 keV and significantly lower than that of the surrounding ICM and far from the temperature versus mass relation of clusters. However, there is no significant excess X-ray emission in the “ID 2” subhalo. Assuming an infall velocity of about 2000 km s^−1, at the border of the excess X-ray emission, the ram pressures for “ID 1” and “ID 32” are comparable to the gravitational restoring force per area. We also studied the effect of the Kelvin–Helmholtz instability to strip the gas. Although we found X-ray clumps associated with the weak-lensing subhalos, their X-ray luminosities are much lower than the total ICM luminosity in the cluster outskirts.
description
We acknowledge the support of a Grant-in-Aid for Scientific Research from the MEXT, No. 25400235 (K.M.), 25800112 (K.S.), and 26800097 (N.O.). This work was supported by “World Premier International Research Center Initiative (WPI Initiative)” and the Funds for the Development of Human Resources in Science and Technology under MEXT, Japan.
journal title
The Astrophysical Journal
volume
Volume 806
issue
Issue 1
start page
123
date of issued
2015-06-10
publisher
IOP Publishing
issn
0004-637X
1538-4357
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
© 2015. The American Astronomical Society. All rights reserved.
relation url
department
Graduate School of Science