%0 Generic %1 salvadori2013metals %A Salvadori, S. %A Tolstoy, E. %A Ferrara, A. %A Zaroubi, S. %D 2013 %K cgm dwarf ionization metallicity %T Metals and ionizing photons from dwarf galaxies %U http://arxiv.org/abs/1309.7058 %X We estimate the potential contribution of M < 10^9 Msun 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 (> 12 Gyr 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%) required to reionize the Milky Way environment. Our fiducial model shows that the gaseous environment can be 50% reionized at z ~ 8 by galaxies with 10^7 Msun < M < 10^8 Msun. At later times, radiative feedback stops the star-formation in these small systems, and reionization is completed by more massive dwarf galaxies by z_rei = 6.40.5. The metals ejected by supernova-driven outflows from M < 10^9 Msun dwarf galaxies almost uniformly fill the Milky Way environment by z ~ 5, enriching it to Z ~ 2 10^-2 Zsun. At z ~ 2 these early metals are still found to represent ~ 50% of the total mass of heavy elements in the circum-Galactic Medium.

@misc{salvadori2013metals, abstract = {We estimate the potential contribution of M < 10^9 Msun 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 (> 12 Gyr 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%) required to reionize the Milky Way environment. Our fiducial model shows that the gaseous environment can be 50% reionized at z ~ 8 by galaxies with 10^7 Msun < M < 10^8 Msun. At later times, radiative feedback stops the star-formation in these small systems, and reionization is completed by more massive dwarf galaxies by z_rei = 6.4\pm 0.5. The metals ejected by supernova-driven outflows from M < 10^9 Msun dwarf galaxies almost uniformly fill the Milky Way environment by z ~ 5, enriching it to Z ~ 2 10^-2 Zsun. At z ~ 2 these early metals are still found to represent ~ 50% of the total mass of heavy elements in the circum-Galactic Medium.}, added-at = {2013-09-30T03:56:31.000+0200}, author = {Salvadori, S. and Tolstoy, E. and Ferrara, A. and Zaroubi, S.}, biburl = {https://www.bibsonomy.org/bibtex/2391352a07b56890823ba0a772f754803/miki}, description = {[1309.7058] Metals and ionizing photons from dwarf galaxies}, interhash = {f4c5219a6ead4df256895fe0046e58a0}, intrahash = {391352a07b56890823ba0a772f754803}, keywords = {cgm dwarf ionization metallicity}, note = {cite arxiv:1309.7058Comment: Accepted for publication in MNRAS letter}, timestamp = {2013-09-30T03:56:31.000+0200}, title = {Metals and ionizing photons from dwarf galaxies}, url = {http://arxiv.org/abs/1309.7058}, year = 2013 }