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ID 47044
file
creator
Futamase, Toshifumi
Kijisawa, Masaru
Kuroshima, Risa
subject
galaxies: clusters: individual (Coma Cluster (A1656)) – gravitational lensing: weak – X-rays: galaxies: clusters
NDC
Astronomy. Space sciences
abstract
We present a 4 deg^2 weak gravitational lensing survey of subhalos in the very nearby Coma cluster using the Subaru/Suprime-Cam. The large apparent size of cluster subhalos allows us to measure the mass of 32 subhalos detected in a model-independent manner, down to the order of 10^−3 of the virial mass of the cluster. Weak-lensing mass measurements of these shear-selected subhalos enable us to investigate subhalo properties and the correlation between subhalo masses and galaxy luminosities for the first time. The mean distortion profiles stacked over subhalos show a sharply truncated feature which is well-fitted by a Navarro–Frenk–White (NFW) mass model with the truncation radius, as expected due to tidal destruction by the main cluster. We also found that subhalo masses, truncation radii, and mass-to-light ratios decrease toward the cluster center. The subhalo mass function, dn/d ln M_sub, in the range of 2 orders of magnitude in mass, is well described by a single power law or a Schechter function. Best-fit power indices of 1.09^+0.42_−0.32 for the former model and 0.99^+0.34_−0.23 for the latter, are in remarkable agreement with slopes of ∼0.9–1.0 predicted by the cold dark matter paradigm. The tangential distortion signals in the radial range of 0.02–2 h^−1 Mpc from the cluster center show a complex structure which is well described by a composition of three mass components of subhalos, the NFW mass distribution as a smooth component of the main cluster, and a lensing model from a large scale structure behind the cluster. Although the lensing signals are 1 order of magnitude lower than those for clusters at z ∼ 0.2, the total signal-to-noise ratio, S/N = 13.3, is comparable, or higher, because the enormous number of background source galaxies compensates for the low lensing efficiency of the nearby cluster.
description
This work was supported by World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan.
journal title
The Astrophysical Journal
volume
Volume 784
issue
Issue 2
start page
90
date of issued
2014-04-01
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
© 2014. The American Astronomical Society. All rights reserved.
relation url
department
Graduate School of Science