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Bubble, bubble, toil, and trouble: 21 cm measurements of the high-redshift universe

Furlanetto, Steven R. (2006) Bubble, bubble, toil, and trouble: 21 cm measurements of the high-redshift universe. New Astronomy Reviews, 50 (1-3). pp. 157-161. ISSN 1387-6473.

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I review the potential insights to be gained from 21 cm measurements of the high-redshift universe. At the highest redshifts (z ~ 30–150), the gas appears in absorption against the cosmic microwave background (CMB) because collisions drive the spin temperature T_S below the CMB temperature T_(CMB). In this epoch, 21 cm fluctuations trace the matter power spectrum and its growth history. At z < 30, collisions become inefficient and T_S → T_(CMB). However, hot collapsed minihalos and proto-filaments in the cosmic web appear in emission, allowing us to trace the beginnings of structure formation. Once the first luminous objects appear, they flood the universe with Lyα photons. Fluctuations in the radiation field induce 21 cm fluctuations through variations in the coupling between the spin and kinetic temperatures of the gas. The temperature fluctuations saturate once the radiation background becomes substantial and X-rays have efficiently heated the universe. During this reionization era the 21 cm signal traces the gas density and the ionization field. The resulting fluctuations will offer enormous insight into the nature of the sources driving reionization and their interactions with the intergalactic medium.

Item Type:Article
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Furlanetto, Steven R.0000-0002-0658-1243
Additional Information:© 2005 Elsevier B.V. Available online 27 December 2005. I thank my collaborators on the projects described here for enlightening discussions: Lars Hernquist, Avi Loeb, Matt McQuinn, Peng Oh, and Matias Zaldarriaga. I also thank the Bard for inspiration throughout this conference.
Subject Keywords:Cosmology-theory; Intergalactic medium
Issue or Number:1-3
Record Number:CaltechAUTHORS:20110224-113159770
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Official Citation:Steven R. Furlanetto, Bubble, bubble, toil, and trouble: 21 cm measurements of the high-redshift universe, New Astronomy Reviews, Volume 50, Issues 1-3, First Light and Reionization: Theoretical Study and Experimental Detection of First Luminous Sources in the Universe, March 2006, Pages 157-161, ISSN 1387-6473, DOI: 10.1016/j.newar.2005.11.022. (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22476
Deposited By: Benjamin Perez
Deposited On:24 Feb 2011 22:58
Last Modified:06 Nov 2019 04:23

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