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dc.contributor.authorJeon, Myoungwon
dc.contributor.authorBesla, Gurtina
dc.contributor.authorBromm, Volker
dc.date.accessioned2018-03-23T16:39:27Z
dc.date.available2018-03-23T16:39:27Z
dc.date.issued2017-10-17
dc.identifier.citationConnecting the First Galaxies with Ultrafaint Dwarfs in the Local Group: Chemical Signatures of Population III Stars 2017, 848 (2):85 The Astrophysical Journalen
dc.identifier.issn1538-4357
dc.identifier.doi10.3847/1538-4357/aa8c80
dc.identifier.urihttp://hdl.handle.net/10150/627108
dc.description.abstractWe investigate the star formation history (SFH) and chemical evolution of isolated analogs of Local Group (LG) ultrafaint dwarf galaxies (UFDs; stellar mass range of 10(2)M(circle dot) < M-*< 10(5) M-circle dot) and gas-rich, low-mass dwarfs (Leo P analogs; stellar mass range of 10(5)M(circle dot) < M-*< 10(6) M-circle dot). We perform a suite of cosmological hydrodynamic zoom-in simulations to follow their evolution from the era of the first generation of stars down to z=0. We confirm that reionization, combined with supernova (SN) feedback, is primarily responsible for the truncated star formation in UFDs. Specifically, halos with a virial mass of M-vir less than or similar to 2 x 10(9) M-circle dot form greater than or similar to 90% of stars prior to reionization. Our work further demonstrates the importance of Population. III stars, with their intrinsically high [C/Fe] yields and the associated external metal enrichment, in producing low-metallicity stars ([Fe/H] less than or similar to -4) and carbon-enhanced metal-poor (CEMP) stars. We find that UFDs are composite systems, assembled from multiple progenitor halos, some of which hosted only Population. II stars formed in environments externally enriched by SNe in neighboring halos, naturally producing extremely low metallicity Population II stars. We illustrate how the simulated chemical enrichment may be used to constrain the SFHs of true observed UFDs. We find that Leo P analogs can form in halos with M-vir similar to 4 x 10(9) M-circle dot 9 (z = 0). Such systems are less affected byreionization and continue to form stars until z = 0, causing higher-metallicity tails. Finally, we predict the existence of extremely low metallicity stars in LG UFD galaxies that preserve the pure chemical signatures of Population III nucleosynthesis.
dc.description.sponsorshipNational Science Foundation [1228509]; NSF [AST-1413501]en
dc.language.isoenen
dc.publisherIOP PUBLISHING LTDen
dc.relation.urlhttp://stacks.iop.org/0004-637X/848/i=2/a=85?key=crossref.76f7e1fbad96f71c2092cf758c35792den
dc.rights© 2017. The American Astronomical Society. All rights reserved.en
dc.subjectcosmology: theoryen
dc.subjectgalaxies: abundancesen
dc.subjectgalaxies: dwarfen
dc.subjectgalaxies: formationen
dc.subjectgalaxies: high-redshiften
dc.subjecthydrodynamicsen
dc.titleConnecting the First Galaxies with Ultrafaint Dwarfs in the Local Group: Chemical Signatures of Population III Starsen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Dept Astronen
dc.identifier.journalThe Astrophysical Journalen
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
refterms.dateFOA2018-09-13T22:44:29Z
html.description.abstractWe investigate the star formation history (SFH) and chemical evolution of isolated analogs of Local Group (LG) ultrafaint dwarf galaxies (UFDs; stellar mass range of 10(2)M(circle dot) < M-*< 10(5) M-circle dot) and gas-rich, low-mass dwarfs (Leo P analogs; stellar mass range of 10(5)M(circle dot) < M-*< 10(6) M-circle dot). We perform a suite of cosmological hydrodynamic zoom-in simulations to follow their evolution from the era of the first generation of stars down to z=0. We confirm that reionization, combined with supernova (SN) feedback, is primarily responsible for the truncated star formation in UFDs. Specifically, halos with a virial mass of M-vir less than or similar to 2 x 10(9) M-circle dot form greater than or similar to 90% of stars prior to reionization. Our work further demonstrates the importance of Population. III stars, with their intrinsically high [C/Fe] yields and the associated external metal enrichment, in producing low-metallicity stars ([Fe/H] less than or similar to -4) and carbon-enhanced metal-poor (CEMP) stars. We find that UFDs are composite systems, assembled from multiple progenitor halos, some of which hosted only Population. II stars formed in environments externally enriched by SNe in neighboring halos, naturally producing extremely low metallicity Population II stars. We illustrate how the simulated chemical enrichment may be used to constrain the SFHs of true observed UFDs. We find that Leo P analogs can form in halos with M-vir similar to 4 x 10(9) M-circle dot 9 (z = 0). Such systems are less affected byreionization and continue to form stars until z = 0, causing higher-metallicity tails. Finally, we predict the existence of extremely low metallicity stars in LG UFD galaxies that preserve the pure chemical signatures of Population III nucleosynthesis.


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