Observing neutral hydrogen above redshift 6: The "global" Perspective

Judd D. Bowman, Alan E.E. Rogers, Jacqueline N. Hewitt

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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.

Original languageEnglish (US)
Title of host publicationThe Evolution of Galaxies Through the Neutral Hydrogen Window
Pages87-89
Number of pages3
DOIs
StatePublished - 2008
EventThe Evolution of Galaxies Through the Neutral Hydrogen Window - Arecibo, Puerto Rico
Duration: Feb 1 2008Feb 3 2008

Publication series

NameAIP Conference Proceedings
Volume1035
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

OtherThe Evolution of Galaxies Through the Neutral Hydrogen Window
CountryPuerto Rico
CityArecibo
Period2/1/082/3/08

Keywords

  • Cosmology
  • Hydrogen
  • Intergalactic medium
  • Reionization

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Observing neutral hydrogen above redshift 6: The "global" Perspective'. Together they form a unique fingerprint.

Cite this