Subaru Weak Lensing Study of Seven Merging Clusters: Distributions of Mass and Baryons
Abstract
We present and compare projected distributions of mass, galaxies, and the intracluster medium (ICM) for a sample of merging clusters of galaxies based on a joint weak-lensing, optical photometric, and X-ray analysis. Our sample comprised seven nearby Abell clusters, for which we had conducted systematic, deep imaging observations with Suprime-Cam on the Subaru Telescope. Our seven target clusters, representing various merging stages and conditions, allowed us to investigate in detail the physical interplay between dark matter, ICM, and galaxies associated with cluster formation and evolution. A1750 and A1758 are binary systems consisting of two cluster-sized components; A520, A754, A1758N, A1758S, and A1914 are on-going cluster mergers; and A2034 and A2142 are cold-front clusters. In the binary clusters, the projected mass, optical light, and X-ray distributions are overall similar and regular without significant substructures. On-going and cold-front merging clusters, on the other hand, reveal highly irregular mass distributions. Overall, the mass distribution appears to be similar to the galaxy luminosity distribution, whereas their distributions are quite different from the ICM distribution in a various ways. We also measured for individual targets global cluster parameters, such as the cluster mass, the mass-to-light ratio, and the ICM temperature. A comparison of the ICM and the virial temperatures of merging clusters from X-ray and weak-lensing analyses, respectively, shows that the ICM temperature of on-going and cold-front clusters is significantly higher than the cluster virial temperature by a factor of ∼2. This temperature excess in the ICM could be explained by the effects of merger boosts.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- April 2008
- DOI:
- 10.1093/pasj/60.2.345
- arXiv:
- arXiv:astro-ph/0702649
- Bibcode:
- 2008PASJ...60..345O
- Keywords:
-
- gravitational lensing;
- galaxies: clusters: individual (Abell520;
- Abell754;
- Abell1750;
- Abell1758;
- Abell1914;
- Abell2034;
- Abell2142);
- X-rays: galaxies: clusters;
- Astrophysics
- E-Print:
- "High-resolution pictures available at http://www.astr.tohoku.ac.jp/~okabe/files/7merger_color.pdf". The published version is available on-line free of charge by the end of 2008 at http://pasj.asj.or.jp/v60/n2/600223/600223.pdf