Halo concentration, galaxy red fraction, and gas properties of optically defined merging clusters
- 12 July 2019
- journal article
- research article
- Published by Oxford University Press (OUP) in Publications of the Astronomical Society of Japan
- Vol. 71 (4)
- https://doi.org/10.1093/pasj/psz059
Abstract
We present multi-wavelength studies of optically defined merging clusters, based on the Hyper Suprime-Cam Subaru Strategic Program. Luminous red galaxies, tracing cluster mass distributions, enable us to identify cluster subhalos at various merging stages, and thus make a homogeneous sample of cluster mergers that is unbiased with respect to the merger boost of the intracluster medium (ICM). We define, using a peak-finding method, merging clusters with multiple peaks and single clusters with single peaks from the CAMIRA cluster catalog. Stacked weak-lensing analysis indicates that our sample of merging clusters is categorized into major mergers. The average halo concentration for the merging clusters is similar to 70% smaller than that of the single-peak clusters, which agrees well with predictions of numerical simulations. The spatial distribution of subhalos is less centrally concentrated than the mass distribution of the main halo. The fractions of red galaxies in the merging clusters are not higher than those of the single-peak clusters. We find a signature of the merger boost of the ICM from the stacked Planck Sunyaev-Zel'dovich effect and ROSAT X-ray luminosity, but not in optical richness. The stacked X-ray surface brightness distribution, aligned with the main subhalo pairs of low-redshift and massive clusters, shows that the central gas core is elongated along the merger axis, and overall gas distribution is misaligned by similar to 60 degrees. The homogeneous, unbiased sample of cluster mergers and multi-wavelength follow-up studies provide a unique opportunity to make a complete picture of merger physics over the whole process.Keywords
Funding Information
- National Astronomical Observatory of Japan
- Ministry of Education, Culture, Sports, Science and Technology
- Japan Society for the Promotion of Science (JP15H05892, JP18K03693)
- Japan Science and Technology Agency
- National Aeronautics and Space Administration (NNX08AR22G)
This publication has 128 references indexed in Scilit:
- DARK MATTER HALO PROFILES OF MASSIVE CLUSTERS: THEORY VERSUS OBSERVATIONSThe Astrophysical Journal, 2013
- Reconstruction of high-resolution Sunyaev–Zeldovich maps from heterogeneous data sets using needletsMonthly Notices of the Royal Astronomical Society, 2013
- MAMPOSSt: Modelling Anisotropy and Mass Profiles of Observed Spherical Systems – I. Gaussian 3D velocitiesMonthly Notices of the Royal Astronomical Society, 2013
- The statistics of CDM halo concentrationsMonthly Notices of the Royal Astronomical Society, 2007
- Weak lensing by galaxies in groups and clusters – I. Theoretical expectationsMonthly Notices of the Royal Astronomical Society, 2006
- Galaxy halo masses and satellite fractions from galaxy-galaxy lensing in the Sloan Digital Sky Survey: stellar mass, luminosity, morphology and environment dependenciesMonthly Notices of the Royal Astronomical Society, 2006
- AnXMM-Newtonobservation of the dynamically active binary cluster A1750Astronomy & Astrophysics, 2004
- A Cluster Merger and the Origin of the Extended Radio Emission in Abell 3667The Astrophysical Journal, 1999
- Infall Regions of Galaxy ClustersThe Astrophysical Journal, 1997
- The evolution of galaxies in clusters. V - A study of populations since Z approximately equal to 0.5The Astrophysical Journal, 1984