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Title: Constraining the Nature of Dark Matter with the Star-formation History of the Faintest Local Group Dwarf Galaxy Satellites

Abstract

Λ warm dark matter (ΛWDM), realized by collisionless particles of 1–3 keV, has been proposed as an alternative scenario to Λ-Cold-Dark Matter (ΛCDM) for the dwarf galaxy scale discrepancies. We present an approach to test the viability of such WDM models using star-formation histories (SFHs) of the dwarf spheroidal galaxies (dSphs) in the Local Group. We compare their high-time-resolution SFHs with the collapse redshift of their dark halos in CDM and WDM. Collapse redshift is inferred after determining the subhalo infall mass. This is based on the dwarf current mass inferred from stellar kinematics, combined with cosmological simulation results on subhalo evolution. WDM subhalos close to the filtering mass scale, forming significantly later than CDM, are the most difficult to reconcile with early truncation of star formation ( z ≥ 3). The ultra-faint dwarfs (UFDs) provide the most stringent constraints. Using six UFDs and eight classical dSphs, we show that a 1 keV particle is strongly disfavored, consistently with other reported methods. Excluding other models is only hinted for a few UFDs. Other UFDs for which the lack of robust constraints on halo mass prevents us from carrying out our analysis rigorously, show a very early onset of star formationmore » that will strengthen the constraints delivered by our method in the future. We discuss the various caveats, notably the low number of dwarfs with accurately determined SFHs and the uncertainties when determining the subhalo infall mass, most notably the baryonic physics. Our preliminary analysis may serve as a pathfinder for future investigations that will combine accurate SFHs for local dwarfs with direct analysis of WDM simulations with baryons.« less

Authors:
;  [1];  [2]
  1. Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)
  2. Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States)
Publication Date:
OSTI Identifier:
22663289
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 845; Journal Issue: 1; 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; BARYONS; COMPARATIVE EVALUATIONS; FILTERS; GALAXIES; KEV RANGE; MASS; NONLUMINOUS MATTER; RED SHIFT; SIMULATION; STAR EVOLUTION; STARS; TIME RESOLUTION

Citation Formats

Chau, Alice, Mayer, Lucio, and Governato, Fabio. Constraining the Nature of Dark Matter with the Star-formation History of the Faintest Local Group Dwarf Galaxy Satellites. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA7E74.
Chau, Alice, Mayer, Lucio, & Governato, Fabio. Constraining the Nature of Dark Matter with the Star-formation History of the Faintest Local Group Dwarf Galaxy Satellites. United States. doi:10.3847/1538-4357/AA7E74.
Chau, Alice, Mayer, Lucio, and Governato, Fabio. Thu . "Constraining the Nature of Dark Matter with the Star-formation History of the Faintest Local Group Dwarf Galaxy Satellites". United States. doi:10.3847/1538-4357/AA7E74.
@article{osti_22663289,
title = {Constraining the Nature of Dark Matter with the Star-formation History of the Faintest Local Group Dwarf Galaxy Satellites},
author = {Chau, Alice and Mayer, Lucio and Governato, Fabio},
abstractNote = {Λ warm dark matter (ΛWDM), realized by collisionless particles of 1–3 keV, has been proposed as an alternative scenario to Λ-Cold-Dark Matter (ΛCDM) for the dwarf galaxy scale discrepancies. We present an approach to test the viability of such WDM models using star-formation histories (SFHs) of the dwarf spheroidal galaxies (dSphs) in the Local Group. We compare their high-time-resolution SFHs with the collapse redshift of their dark halos in CDM and WDM. Collapse redshift is inferred after determining the subhalo infall mass. This is based on the dwarf current mass inferred from stellar kinematics, combined with cosmological simulation results on subhalo evolution. WDM subhalos close to the filtering mass scale, forming significantly later than CDM, are the most difficult to reconcile with early truncation of star formation ( z ≥ 3). The ultra-faint dwarfs (UFDs) provide the most stringent constraints. Using six UFDs and eight classical dSphs, we show that a 1 keV particle is strongly disfavored, consistently with other reported methods. Excluding other models is only hinted for a few UFDs. Other UFDs for which the lack of robust constraints on halo mass prevents us from carrying out our analysis rigorously, show a very early onset of star formation that will strengthen the constraints delivered by our method in the future. We discuss the various caveats, notably the low number of dwarfs with accurately determined SFHs and the uncertainties when determining the subhalo infall mass, most notably the baryonic physics. Our preliminary analysis may serve as a pathfinder for future investigations that will combine accurate SFHs for local dwarfs with direct analysis of WDM simulations with baryons.},
doi = {10.3847/1538-4357/AA7E74},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 845,
place = {United States},
year = {2017},
month = {8}
}