2004/09/17 by Bence Kocsis, Zoltan Haiman, Zsolt Frei
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/427975
published as Astrophys.J. 623 (2005) 632-649 · 15 pages, submitted to ApJ
arxiv created 2004/09/17 · openalex publication_date 2005/04/15 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
In cosmological structure formation models, massive nonlinear objects in the process of formation, such as galaxy clusters, are surrounded by large-scale shocks at or around the expected virial radius. Direct observational evidence for such virial shocks is currently lacking, but we show here that their presence can be inferred from future, high-resolution, high-sensitivity observations of the Sunyaev-Zel'dovich (SZ) effect in galaxy clusters. We study the detectability of virial shocks in mock SZ maps, using simple models of cluster structure (gas density and temperature distributions) and noise (background and foreground galaxy clusters projected along the line of sight, as well as the cosmic microwave background anisotropies). We find that at an angular resolution of 2'' and sensitivity of 10 μK, expected to be reached at ~100 GHz frequencies in a ~20 hr integration (for a cluster at z ~ 2) with the forthcoming ALMA instrument, virial shocks associated with massive ( M ~ 10 15 M ☉ ) clusters will stand out from the noise and can be detected at high significance. More generally, our results imply that the projected SZ surface brightness profile in future, high-resolution experiments will provide sensitive constraints on the density profile of cluster gas.