2010/09/30 by Rajat M. Thomas, Saleem Zaroubi · 21 citations
Physics and Astronomy · #Astronomy #Astrophysics #Brightness #Brightness temperature #COSMIC cancer database #Cosmic background radiation #Cosmic microwave background #Cosmology #Cosmology and Gravitation Theories #Dark Ages #Decoupling (probability) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Physics #QSOS #Quantum mechanics #Radio Astronomy Observations and Technology #Redshift #Reionization #Star formation #Stars #astro-ph.CO
paper · pdf · doi:10.1111/j.1365-2966.2010.17525.x
published in Monthly Notices of the Royal Astronomical Society 410(2), 1377-1390 (Oxford University Press) · 15 pages, 18 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society
arxiv created 2010/09/30 · openalex publication_date 2010/10/11 · arxiv updated 2015/05/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Simulations estimating the brightness temperature (δTb) of the redshifted 21 cm from the epoch of reionization (EoR) often assume that the spin temperature (Ts) is decoupled from the background cosmic microwave background (CMB) temperature and is much larger than it, i.e. Ts≫TCMB. Although a valid assumption towards the later stages of the reionization process, it does not necessarily hold at the earlier epochs. Violation of this assumption will lead to fluctuations in δTb that are driven neither by density fluctuations nor by H ii regions. Therefore, it is vital to calculate the spin temperature self-consistently by treating the Lyα and collisional coupling of Ts to the kinetic temperature, Tk. In this paper we develop an extension to the bears algorithm, originally developed to model reionization history, to include these coupling effects. Here, we simulate the effect in ionization and heating for three models in which the reionization is driven by stars, mini-QSOs or a mixture of both. We also perform a number of statistical tests to quantify the imprint of the self-consistent inclusion of the spin-temperature decoupling from the CMB. We find that the evolution of the spin temperature has an impact on the measured signal especially at redshifts higher than 10 and such evolution should be taken into account when one attempts to interpret the observational data.