2003/12/31 by Taotao Fang, T. Fang, M. White +1 · 2 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #Solar and Space Plasma Dynamics #astro-ph
paper · pdf · doi:10.1086/420965
published as Astrophys.J.606:L9-L12,2004 · 4 pages, 2 figures. Minor revisions, accepted by ApJ Letters
arxiv created 2004/03/15 · openalex publication_date 2004/04/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
Gravitational instability induces a simple correlation between the large- and small-scale fluctuations of the Lyα flux spectrum. However, nongravitational processes involved in structure formation and evolution will alter such a correlation. In this Letter, we explore how scatter in the temperature-density relation of the intergalactic medium reduces the gravitationally induced scale-scale correlation. By examining whether or not observations of the correlation are close to that predicted by pure gravity, we put constraints on the scatter in the ρ- T relation and in turn on any physical process that would lead to scatter, e.g., strong fluctuations in the UV background or radiative transfer effects. By applying this method to high-resolution Keck spectra of Q1422+231 and HS 1946+7658, we find the predicted correlation signal induced by gravity and the diminishing of this correlation signal at small scales. This suggests extra physics affects the small-scale structure of the forest, and we can constrain the scatter in the ρ- T relation to a conservative 20% upper limit. A crude model suggests, if there is any spatial correlation of temperature, the coherence length scale must be smaller than ~0.3 h -1 Mpc to be consistent with the Keck data.