Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-09-17
Astrophys.J.636:1-7,2005
Astronomy and Astrophysics
Astrophysics
21 pages, 4 figures, 1 table. Accepted for publication in Astrophysical Journal
Scientific paper
10.1086/497882
The first galaxies in the Universe are built up where cold dark matter (CDM) forms large scale filamentary structure. Although the galaxies are expected to emit numerous Lya photons, they are surrounded by plentiful neutral hydrogen with a typical optical depth for Lya of ~10^5 (HI halos) before the era of cosmological reionization. The HI halo almost follows the cosmological Hubble expansion with some anisotropic corrections around the galaxy because of the gravitational attraction by the underlying CDM filament. In this paper, we investigate the detectability of the Lya emissions from the first galaxies, examining their dependence on viewing angles. Solving the Lya line transfer problem in an anisotropically expanding HI halo, we show that the escape probability from the HI halo is the largest in direction along the filament axis. If the Lya source is observed with a narrow-band filter, the difference of apparent Lya line luminosities among viewing angles can be a factor of > 40 at an extreme case. Furthermore, we evaluate the predicted physical features of the Lya sources and flux magnification by gravitational lensing effect due to clusters of galaxies along the filament. We conclude that, by using the next generation space telescopes like the JWST, the Lya emissions from the first galaxies whose CDM filament axes almost face to us can be detected with the S/N of > 10.
Kamaya Hideyuki
Kobayashi Masakazu A. R.
Yonehara Atsunori
No associations
LandOfFree
Lyman Alpha Line Spectra of the First Galaxies: Dependence on Observed Direction to the Underlying CDM Filament 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 Lyman Alpha Line Spectra of the First Galaxies: Dependence on Observed Direction to the Underlying CDM Filament, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lyman Alpha Line Spectra of the First Galaxies: Dependence on Observed Direction to the Underlying CDM Filament will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-87029