Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-10-05
Astrophys.J.626:1-11,2005
Astronomy and Astrophysics
Astrophysics
11 pages, 7 figures, ApJ, published. Normalization fixed in top panels of Figures 4-7
Scientific paper
10.1086/429954
The first galaxies that formed at a redshift ~20-30 emitted continuum photons with energies between the Lyman-alpha and Lyman limit wavelengths of hydrogen, to which the neutral universe was transparent except at the Lyman-series resonances. As these photons redshifted or scattered into the Lyman-alpha resonance they coupled the spin temperature of the 21cm transition of hydrogen to the gas temperature, allowing it to deviate from the microwave background temperature. We show that the fluctuations in the radiation emitted by the first galaxies produced strong fluctuations in the 21cm flux before the Lyman-alpha coupling became saturated. The fluctuations were caused by biased inhomogeneities in the density of galaxies, along with Poisson fluctuations in the number of galaxies. Observing the power-spectra of these two sources would probe the number density of the earliest galaxies and the typical mass of their host dark matter halos. The enhanced amplitude of the 21cm fluctuations from the era of Lyman-alpha coupling improves considerably the practical prospects for their detection.
Barkana Rennan
Loeb Abraham
No associations
LandOfFree
Detecting the Earliest Galaxies Through Two New Sources of 21cm Fluctuations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Detecting the Earliest Galaxies Through Two New Sources of 21cm Fluctuations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Detecting the Earliest Galaxies Through Two New Sources of 21cm Fluctuations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-169307