The imprint of reionization on the star formation histories of dwarf galaxies
EntityUAM. Departamento de Física Teórica
PublisherOxford University Press
10.1093/mnras/stv925Monthly Notices of the Royal Astronomical Society 450.4 (2015): 4207-4220
ISSN0035-8711 (print); 1365-2966 (online)
Funded byThis work was supported in part by the National Science Foundation under Grant No. PHYS-1066293. Our collaboration has been supported by DFG grants GO 563/21-1 and GO 563/24-1 as well as by CONICET. ABL, JFN and MGA aknowledge support from ANPCyT grant PICT2012-1137. GY acknowledges financial support from MINECO under research grants AYA2012-31101. FPA2012-34694 and MultiDark CSD2009-00064. YH has been partially supported by the Israel Science Foundation (13/08)
ProjectGobierno de España. AYA2012-31101; Gobierno de España. FPA2012-34694; Gobierno de España. CSD2009-00064
SubjectsCosmology: dark ages, reionization, first stars; Galaxies: Local Group; Galaxies: dwarf; Galaxies: stellar content; Galaxies: formation; Galaxies: evolution; Física
NoteThis article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved
Rights© 2015 The Authors
We use a compilation of star formation histories (SFHs) and cosmological simulations to explore the impact of cosmic reionization on nearby isolated dwarf galaxies. Nearby dwarfs show a wide diversity of SFHs; from ancient systems that completed their star formation (SF) ~10 Gyr ago to young dwarfs that formed themajority of their stars in the past~5Gyr to 'twocomponent' systems characterized by the overlap of old and young stars. As an ensemble, SF in nearby dwarfs dips to lower-than-average rates at intermediate times (4<t/Gyr<8), a feature caused in the simulation by cosmic reionization. Reionization heats the gas and drives it out of low-mass haloes, affecting especially systems with virial temperatures of ~2 × 104 K at zreion. SF begins before zreion in systems above this threshold; its associated feedback compounds the effects of reionization, emptying the haloes of gas and leaving behind old stellar systems. In haloes below the threshold at zreion, reionization leads to a delay in the onset of SF that lasts until the halo grows massive enough to allow gas to cool and form stars, leading to a system with a prominent young stellar component. 'Two-component' systems may be traced to late accretion events that allow young stars to form in systems slightly above the threshold at zreion. The dearth of intermediate-age stars in nearby dwarfs might be the clearest signature of the imprint of cosmic reionization on the SFHs of dwarf galaxie
Google Scholar:Beńitez-Llambay, A. - Navarro, J. F. - Abadi, Mario G. - Gottlöber, S. - Yepes Alonso, Gustavo - Hoffman, Y. - Steinmetz, M.
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