Clash of Titans: A MUSE dynamical study of the extreme cluster merger SPT-CL J0307-6225
Abstract
We present MUSE spectroscopy, Megacam imaging, and Chandra X-ray emission for SPT-CL J0307-6225, a $z = 0.58$ major merging galaxy cluster with a large BCG-SZ centroid separation and a highly disturbed X-ray morphology. The galaxy density distribution shows two main overdensities with separations of 0.144 and 0.017 arcmin to their respective BCGs. We characterize the central regions of the two colliding structures, namely 0307-6225N and 0307-6225S, finding velocity derived masses of M200, N = 2.44 ± 1.41 × 1014M⊙ and M200, S = 3.16 ± 1.88 × 1014M⊙, with a line-of-sight velocity difference of |Δv| = 342 km s−1. The total dynamically derived mass is consistent with the SZ derived mass of 7.63 h$_{70}^{-1}$ ± 1.36 × 1014M⊙. We model the merger using the Monte Carlo Merger Analysis Code, estimating a merging angle of 36$^{+14}_{-12}$ ° with respect to the plane of the sky. Comparing with simulations of a merging system with a mass ratio of 1:3, we find that the best scenario is that of an ongoing merger that began 0.96$^{+0.31}_{-0.18}$ Gyr ago. We also characterize the galaxy population using Hδ and [O ii] λ3727 Å lines. We find that most of the emission-line galaxies belong to 0307-6225S, close to the X-ray peak position with a third of them corresponding to red-cluster sequence galaxies, and the rest to blue galaxies with velocities consistent with recent periods of accretion. Moreover, we suggest that 0307-6225S suffered a previous merger, evidenced through the two equally bright BCGs at the centre with a velocity difference of ∼674 km s−1.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 03, 2022
- Source ID
- 10.1093/mnras/stac2480
Entities
People
- A Diaz-ocampo
- A Zenteno
- A. Saro
- Amelia Ramirez
- Anja Katzenberger
- B Stalder
- Benjamin Floyd
- D Hernández-lang
- Diego Pallero
- Eleazar Rodrigo Carrasco
- F A Gómez
- Franklin Aldás
- G Garmire
- G K T Hau
- Guillaume Mahler
- H Cuevas
- J L Nilo Castellon
- J Wynter
- John Clancy
- Keunho Kim
- M Bayliss
- M. Mcdonald
- Michael L. Klein
- P. Prado
- Rogério Monteiro-Oliveira
- Taweewat Somboonpanyakul
Organizations
- Academia Sinica
- Air Force Office of Scientific Research
- Cerro Tololo Inter-American Observatory
- Chilean National Agency for Research and Development
- European Research Council
- European Southern Observatory
- Food Allergy Research & Education
- Gemini Observatory
- German Research Foundation
- Harvard–Smithsonian Center for Astrophysics
- Institute for Fundamental Physics of the Universe
- Istituto Nazionale di Fisica Nucleare
- Ludwig-Maximilians-Universität München
- Massachusetts Institute of Technology
- Max Planck Society
- Ministry of Education, Universities and Research
- National Fund for Scientific and Technological Development
- National Institute for Astrophysics
- Potsdam Institute for Climate Impact Research
- State University of Santa Cruz
- University of Cincinnati
- University of La Serena
- University of Melbourne
- University of Michigan
- University of Missouri–Kansas City
- University of Potsdam
- University of Trieste
- University of Valparaíso