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Title: CHEMICAL SIGNATURES OF THE FIRST GALAXIES: CRITERIA FOR ONE-SHOT ENRICHMENT

Abstract

We utilize metal-poor stars in the local, ultra-faint dwarf galaxies (UFDs; L {sub tot} {<=} 10{sup 5} L {sub Sun }) to empirically constrain the formation process of the first galaxies. Since UFDs have much simpler star formation histories than the halo of the Milky Way, their stellar populations should preserve the fossil record of the first supernova (SN) explosions in their long-lived, low-mass stars. Guided by recent hydrodynamical simulations of first galaxy formation, we develop a set of stellar abundance signatures that characterize the nucleosynthetic history of such an early system if it was observed in the present-day universe. Specifically, we argue that the first galaxies are the product of chemical 'one-shot' events, where only one (long-lived) stellar generation forms after the first, Population III, SN explosions. Our abundance criteria thus constrain the strength of negative feedback effects inside the first galaxies. We compare the stellar content of UFDs with these one-shot criteria. Several systems (Ursa Major II, and also Coma Berenices, Bootes I, Leo IV, Segue 1) largely fulfill the requirements, indicating that their high-redshift predecessors did experience strong feedback effects that shut off star formation. We term the study of the entire stellar population of a dwarfmore » galaxy for the purpose of inferring details about the nature and origin of the first galaxies 'dwarf galaxy archaeology'. This will provide clues to the connection of the first galaxies, the surviving, metal-poor dwarf galaxies, and the building blocks of the Milky Way.« less

Authors:
 [1];  [2]
  1. Massachusetts Institute of Technology and Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Ave, Cambridge, MA 02139 (United States)
  2. Department of Astronomy and Texas Cosmology Center, University of Texas at Austin, 2511 Speedway, Austin, TX 78712-0259 (United States)
Publication Date:
OSTI Identifier:
22086396
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 759; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; COSMOLOGY; DWARF STARS; ELEMENT ABUNDANCE; HYDRODYNAMICS; METALS; MILKY WAY; RED SHIFT; UNIVERSE

Citation Formats

Frebel, Anna, and Bromm, Volker, E-mail: afrebel@mit.edu, E-mail: vbromm@astro.as.utexas.edu. CHEMICAL SIGNATURES OF THE FIRST GALAXIES: CRITERIA FOR ONE-SHOT ENRICHMENT. United States: N. p., 2012. Web. doi:10.1088/0004-637X/759/2/115.
Frebel, Anna, & Bromm, Volker, E-mail: afrebel@mit.edu, E-mail: vbromm@astro.as.utexas.edu. CHEMICAL SIGNATURES OF THE FIRST GALAXIES: CRITERIA FOR ONE-SHOT ENRICHMENT. United States. doi:10.1088/0004-637X/759/2/115.
Frebel, Anna, and Bromm, Volker, E-mail: afrebel@mit.edu, E-mail: vbromm@astro.as.utexas.edu. Sat . "CHEMICAL SIGNATURES OF THE FIRST GALAXIES: CRITERIA FOR ONE-SHOT ENRICHMENT". United States. doi:10.1088/0004-637X/759/2/115.
@article{osti_22086396,
title = {CHEMICAL SIGNATURES OF THE FIRST GALAXIES: CRITERIA FOR ONE-SHOT ENRICHMENT},
author = {Frebel, Anna and Bromm, Volker, E-mail: afrebel@mit.edu, E-mail: vbromm@astro.as.utexas.edu},
abstractNote = {We utilize metal-poor stars in the local, ultra-faint dwarf galaxies (UFDs; L {sub tot} {<=} 10{sup 5} L {sub Sun }) to empirically constrain the formation process of the first galaxies. Since UFDs have much simpler star formation histories than the halo of the Milky Way, their stellar populations should preserve the fossil record of the first supernova (SN) explosions in their long-lived, low-mass stars. Guided by recent hydrodynamical simulations of first galaxy formation, we develop a set of stellar abundance signatures that characterize the nucleosynthetic history of such an early system if it was observed in the present-day universe. Specifically, we argue that the first galaxies are the product of chemical 'one-shot' events, where only one (long-lived) stellar generation forms after the first, Population III, SN explosions. Our abundance criteria thus constrain the strength of negative feedback effects inside the first galaxies. We compare the stellar content of UFDs with these one-shot criteria. Several systems (Ursa Major II, and also Coma Berenices, Bootes I, Leo IV, Segue 1) largely fulfill the requirements, indicating that their high-redshift predecessors did experience strong feedback effects that shut off star formation. We term the study of the entire stellar population of a dwarf galaxy for the purpose of inferring details about the nature and origin of the first galaxies 'dwarf galaxy archaeology'. This will provide clues to the connection of the first galaxies, the surviving, metal-poor dwarf galaxies, and the building blocks of the Milky Way.},
doi = {10.1088/0004-637X/759/2/115},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}