2014MNRAS.437L..26S -
Mon. Not. R. Astron. Soc., 437, L26-L30 (2014/January-1)
Metals and ionizing photons from dwarf galaxies.
SALVADORI S., TOLSTOY E., FERRARA A. and ZAROUBI S.
Abstract (from CDS):
We estimate the potential contribution of M < 109M☉ dwarf galaxies to the reionization and early metal enrichment of the Milky Way environment, or circum-Galactic medium. Our approach is to use the observed properties of ancient stars ( ≳ 12Gyr old) measured in nearby dwarf galaxies to characterize the star formation at high z. We use a merger-tree model for the build-up of the Milky Way, which self-consistently accounts for feedback processes, and which is calibrated to match the present-day properties of the Galaxy and its dwarf satellites. We show that the high-z analogues of nearby dwarf galaxies can produce the bulk of ionizing radiation (>80 percent) required to reionize the Milky Way environment. Our fiducial model shows that the gaseous environment can be 50 percent reionized at z ~ 8 by galaxies with 107M☉ ≤ M < 108M☉. At later times, radiative feedback stops the star formation in these small systems, and reionization is completed by more massive dwarf galaxies by zrei = 6.4±0.5. The metals ejected by supernova-driven outflows from M < 109M☉ dwarf galaxies almost uniformly fill the Milky Way environment by z ~ 5, enriching it to Z ~ 2x10–2Z☉. At z ~ 2, these early metals are still found to represent the ~50 percent of the total mass of heavy elements in the circum-Galactic medium.
Abstract Copyright:
© 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society (2013)
Journal keyword(s):
galaxies: dwarf - galaxies: high-redshift - Local Group - cosmology: theory
Simbad objects:
2
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