Abstract
Shocks produced by the accretion of infalling gas in the outskirts of galaxy clusters are expected in the hierarchical structure formation scenario, as found in cosmological hydrodynamical simulations. Here, we report the detection of a shock front at a large radius in the pressure profile of the galaxy cluster A2319 at a significance of 8.6σ, using Planck thermal Sunyaev-Zel'dovich data. The shock is located at (2.93 ± 0.05) × R500 and is not dominated by any preferential radial direction. Using a parametric model of the pressure profile, we derive a lower limit on the Mach number of the infalling gas, > 3.25 at 95% confidence level. These results are consistent with expectations derived from hydrodynamical simulations. Finally, we use the shock location to constrain the accretion rate of A2319 to (1.4 ± 0.4) × 1014 M Gyr-1 for a total mass of M200 1015 M .
Original language | American English |
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Article number | A136 |
Journal | Astronomy and Astrophysics |
Volume | 622 |
DOIs | |
State | Published - 1 Feb 2019 |
Keywords
- Cosmic background radiation
- Galaxies: clusters: individual: A2319
- Galaxies: clusters: intracluster medium
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science