2006/11/30 by Hajime Kawahara, Yasushi Suto, Tetsu Kitayama +4
Mathematics · Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Function (biology) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Intracluster medium #Log-normal distribution #Mathematics #Physics #Statistical physics #Statistics #astro-ph
paper · pdf · doi:10.1086/512231
published as Astrophys.J.659:257-266,2007 · 17 pages,10 figures, accepted to ApJ, Minor changes
arxiv created 2007/01/04 · openalex publication_date 2007/04/06 · arxiv updated 2011/02/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
The origin of the recently reported systematic bias in the spectroscopic temperature of galaxy clusters is investigated using a cosmological hydrodynamic simulation. We find that the local inhomogeneities of the gas temperature and density, after being corrected for their global radial profiles, have a nearly universal distribution that resembles a lognormal function. Based on this lognormal approximation for the fluctuations in the intracluster medium, we develop an analytical model that explains the bias in the spectroscopic temperature. We conclude that the multiphase nature of the intracluster medium, due not only to the radial profiles but also to the local inhomogeneities, plays an essential role in producing the systematic bias.