The Bulletin of The Korean Astronomical Society (천문학회보)

The Korean Astronomical Society (한국천문학회)
권호 표지

Discovery of a Radio Relic in the Massive Merging Cluster SPT-CL J2023-5535 from the ASKAP-EMU Pilot Survey

  • Kim, HyeongHan (Yonsei University, Department of Astronomy) ;
  • Jee, M. James (Yonsei University, Department of Astronomy) ;
  • Rudnick, Lawrence (Minnesota Institute for Astrophysics, University of Minnesota) ;
  • Parkinson, David (Korea Astronomy and Space Science Institute) ;
  • Finner, Kyle (Yonsei University, Department of Astronomy) ;
  • Yoon, Mijin (Yonsei University, Department of Astronomy) ;
  • Lee, Wonki (Yonsei University, Department of Astronomy) ;
  • Brunetti, Giangranco (Istituto Nazionale di Astrofisica, Istituto di Radioastronomia) ;
  • Bruggen, Marcus (Hamburger Sternwarte, Universitat Hamburg) ;
  • Collier, Jordan D. (Inter-University Institute for Data Intensive Astronomy, Department of Astronomy, University of Cape Town) ;
  • Hopkins, Andrew M. (Australian Astronomical Optics, Macquarie University) ;
  • Michalowski, Michal J. (Astronomical Observatory Institute, Faculty of Physics, Adam Mickiewicz University) ;
  • Norris, Ray P. (Western Sydney University) ;
  • Riseley, Chris (Dipartimento di Fisica e Astronomia, Universita degli Studi di Bologna)
  • Published : 2020.10.13
Download PDF
⟨ Previous Next ⟩

Abstract

The ASKAP-EMU survey is a deep wide-field radio continuum survey designed to cover the entire southern sky and a significant fraction of the northern sky up to +30°. Here, we report a discovery of a radio relic in the merging cluster SPT-CL J2023-5535 at z=0.23 from the ASKAP-EMU pilot 300 square degree survey (800-1088 MHz). The deep high-resolution data reveal a ~2 Mpc-scale radio halo elongated in the east-west direction, coincident with the intracluster gas. The radio relic is located at the western edge of this radio halo stretched ~0.5 Mpc in the north-south orientation. The integrated spectral index of the radio relic within the narrow bandwidth is α1088MHz800MHz = -0.76 ± 0.06. Our weak-lensing analysis shows that the system is massive (M200 = 1.04 ± 0.36 × 1015M⊙) and composed of at least three subclusters. We suggest a scenario, wherein the radio features arise from the collision between the eastern and middle subclusters. Furthermore, the direct link between the local AGN and the relic along with the discontinuities in X-ray observation hint us that we are looking at the site of re-acceleration.

Keywords