CaltechAUTHORS
  A Caltech Library Service

Observing Neutral Hydrogen Above Redshift 6: The “Global” Perspective

Bowman, Judd D. and Rogers, Alan E. E. and Hewitt, Jacqueline N. (2008) Observing Neutral Hydrogen Above Redshift 6: The “Global” Perspective. In: The Evolution of Galaxies through the Neutral Hydrogen Window, Arecibo Observatory (Puerto Rico), 1–3 February 2008. AIP Conference Proceedings. No.1035. American Institute of Physics , Melville, NY, pp. 87-89. ISBN 978-0-7354-0558-5. http://resolver.caltech.edu/CaltechAUTHORS:BOWaipcp08a

[img]
Preview
PDF - Published Version
See Usage Policy.

208Kb

Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:BOWaipcp08a

Abstract

Above redshift 6, the dominant source of neutral hydrogen in the Universe shifts from localized clumps in and around galaxies and filaments to a pervasive, diffuse component of the intergalactic medium (IGM). This transition tracks the global neutral fraction of hydrogen in the IGM and can be studied, in principle, through the redshifted 21 cm hyperfine transition line. During the last half of the reionization epoch, the mean (global) brightness temperature of the redshifted 21 cm emission is proportional to the neutral fraction, but at earlier times (10<z<25), the mean brightness temperature should probe the spin temperature of neutral hydrogen in the IGM. Measuring the (of order 10 mK) mean brightness temperature of the redshifted 21 cm line as a function of frequency (and hence redshift) would chart the early evolution of galaxies through the heating and ionizing of the IGM by their stellar populations. Experiments are already underway to accomplish this task or, at least, provide basic constraints on the evolution of the mean brightness temperature. We provide a brief overview of one of these projects, the Experiment to the Detect the Global EOR Signature (EDGES), and discuss prospects for future results.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1063/1.2973620DOIArticle
http://link.aip.org/link/?APCPCS/1035/87/1PublisherArticle
Additional Information:© 2008 American Institute of Physics. Issue Date: 1 August 2008. This work was supported by the Massachusetts Institute of Technology, School of Science, and by the NSF through grant AST-0457585. JDB is supported by NASA through Hubble Fellowship grant HF-01205.01-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555.
Funders:
Funding AgencyGrant Number
Massachuttes Institute of TechnologyUNSPECIFIED
NSFAST-0457585
NASAHF-01205.01-A
NASANAS 5-26555
Subject Keywords:cosmology, intergalactic matter, red shift, clusters of galaxies, cosmic background radiation, ionization, astronomical telescopes
Record Number:CaltechAUTHORS:BOWaipcp08a
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:BOWaipcp08a
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12424
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:25 Nov 2008 19:16
Last Modified:19 Apr 2016 22:50

Repository Staff Only: item control page