SUBARU WEAK-LENSING STUDY OF A2163: BIMODAL MASS STRUCTURE
- Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), P.O. Box 23-141, Taipei 10617, Taiwan (China)
- Dipartimento di Fisica, Universita degli Studi di Roma 'Tor Vergata', via della Ricerca Scientifica 1, 00133 Roma (Italy)
- Universite de Nice Sophia-Antipolis, CNRS, Laboratoire Cassiopee, CNRS, UMR 6202, Observatoire de la Cote d' Azur, BP4229, 06304 Nice Cedex 4 (France)
We present a weak-lensing analysis of the merging cluster A2163 using Subaru/Suprime-Cam and CFHT/Mega-Cam data and discuss the dynamics of this cluster merger, based on complementary weak-lensing, X-ray, and optical spectroscopic data sets. From two-dimensional multi-component weak-lensing analysis, we reveal that the cluster mass distribution is well described by three main components including the two-component main cluster A2163-A with mass ratio 1:8, and its cluster satellite A2163-B. The bimodal mass distribution in A2163-A is similar to the galaxy density distribution, but appears as spatially segregated from the brightest X-ray emitting gas region. We discuss the possible origins of this gas-dark-matter offset and suggest the gas core of the A2163-A subcluster has been stripped away by ram pressure from its dark matter component. The survival of this gas core from the tidal forces exerted by the main cluster lets us infer a subcluster accretion with a non-zero impact parameter. Dominated by the most massive component of A2163-A, the mass distribution of A2163 is well described by a universal Navarro-Frenk-White profile as shown by a one-dimensional tangential shear analysis, while the singular-isothermal sphere profile is strongly ruled out. Comparing this cluster mass profile with profiles derived assuming intracluster medium hydrostatic equilibrium (H.E.) in two opposite regions of the cluster atmosphere has allowed us to confirm the prediction of a departure from H.E. in the eastern cluster side, presumably due to shock heating. Yielding a cluster mass estimate of M{sub 500} = 11.18{sup +1.64}{sub -1.46} Multiplication-Sign 10{sup 14} h {sup -1} M{sub Sun }, our mass profile confirms the exceptionally high mass of A2163, consistent with previous analyses relying on the cluster dynamical analysis and Y{sub X} mass proxy.
- OSTI ID:
- 21612671
- Journal Information:
- Astrophysical Journal, Vol. 741, Issue 2; Other Information: DOI: 10.1088/0004-637X/741/2/116; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
COSMOLOGY
GALAXY CLUSTERS
IMPACT PARAMETER
MASS
MASS DISTRIBUTION
NONLUMINOUS MATTER
ONE-DIMENSIONAL CALCULATIONS
SATELLITES
SHOCK HEATING
TWO-DIMENSIONAL CALCULATIONS
X-RAY GALAXIES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DISTRIBUTION
GALAXIES
HEATING
MATTER
PLASMA HEATING
SPATIAL DISTRIBUTION