Hidenobu Yajima, Yuexing Li, Qirong Zhu, Tom Abel, Caryl Gronwall, Robin Ciardullo
The Lya emission has been observed from galaxies over a redshift span z ~ 0 -
8.6. However, the link between high-redshift Lya emitters (LAEs) and local
galaxies is largely unknown. Here, we investigate the Lya properties of
progenitors of a local L^{*} galaxy by combining cosmological hydrodynamic
simulations with three-dimensional radiative transfer calculations using the
new ART^2 code. We find that the modeled galaxies are Lya bright in redshift z=
0 - 10. In particular, the Lya luminosities of some massive progenitors at z ~
2 - 6 are close to the observed characteristic L_{Lya}^{*} of LAEs in that
redshift range. Both Lya photon escape fraction and line equivalent width
increase with redshift. The Lya escape fraction correlates with a number of
physical properties of the galaxy, such as mass, SFR and metallicity. We find a
"viewing-angle scatter" in which the photon escape depends strongly on the
galaxy morphology and orientation. Moreover, we find that high-redshift LAEs
show blue-shifted Lya line profiles characteristic of gas inflow, and that the
Lya emission by excitation cooling increases with redshift, and becomes
dominant at z > 6. Our results suggest that galaxies at high redshift form
through accretion of cold gas, and that the observed LAEs at z ~ 2-6 with
luminosity of L ~ 10^{42-43} erg/s may evolve into present-day L^{*} galaxies.
View original:
http://arxiv.org/abs/1112.1031
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