Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 2019 | Submitted + Published
Journal Article Open

Be it therefore resolved: cosmological simulations of dwarf galaxies with 30 solar mass resolution

Abstract

We study a suite of extremely high-resolution cosmological Feedback in Realistic Environments simulations of dwarf galaxies (⁠M_(halo) ≲ 10¹⁰ M⊙⁠), run to z = 0 with 30M⊙ resolution, sufficient (for the first time) to resolve the internal structure of individual supernovae remnants within the cooling radius. Every halo with M_(halo) ≳ 10_(8.6) M⊙ is populated by a resolved stellar galaxy, suggesting very low-mass dwarfs may be ubiquitous in the field. Our ultra-faint dwarfs (UFDs; M∗ < 10⁵ M⊙⁠) have their star formation (SF) truncated early (z ≳ 2), likely by reionization, while classical dwarfs (⁠M∗ > 10⁵ M⊙) continue forming stars to z < 0.5. The systems have bursty star formation histories, forming most of their stars in periods of elevated SF strongly clustered in both space and time. This allows our dwarf with M*/M_(halo) > 10⁻⁴ to form a dark matter core > 200pc, while lower mass UFDs exhibit cusps down to ≲ 100pc⁠, as expected from energetic arguments. Our dwarfs with M∗ > 10₄ M⊙ have half-mass radii (R_(1/2)) in agreement with Local Group (LG) dwarfs (dynamical mass versus R_(1/2) and stellar rotation also resemble observations). The lowest mass UFDs are below surface brightness limits of current surveys but are potentially visible in next-generation surveys (e.g. LSST). The stellar metallicities are lower than in LG dwarfs; this may reflect pre-enrichment of the LG by the massive hosts or Pop-III stars. Consistency with lower resolution studies implies that our simulations are numerically robust (for a given physical model).

Additional Information

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2019 October 4. Received 2019 September 6; in original form 2018 November 30. Published: 16 October 2019. CW is supported by the Lee A. DuBridge Postdoctoral Scholarship in Astrophysics. Support for PFH and SGK was provided by an Alfred P. Sloan Research Fellowship, NSF Collaborative Research Grant #1715847 and CAREER grant #1455342, and NASA grants NNX15AT06G, JPL 1589742, 17-ATP17-0214. ABP acknowledges generous support from the George P. and Cynthia Woods Institute for Fundamental Physics and Astronomy at Texas A&M University. SGK acknowledges additional support by NASA through Einstein Postdoctoral Fellowship grant number PF5-160136 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. MBK acknowledges support from NSF grant AST-1517226 and CAREER grant AST-1752913 and from NASA grants NNX17AG29G and HST-AR-13888, HST-AR-13896, HST-AR-14282, HST-AR-14554, HST-AR-15006, HST-GO-12914, and HST-GO-14191 from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. AW received support from NASA, through ATP grant 80NSSC18K1097 and HST grants GO-14734 and AR-15057 from STScI, and a Hellman Fellowship from UC Davis. CAFG was supported by NSF through grants AST-1517491, AST-1715216, and CAREER award AST-1652522, by NASA through grants NNX15AB22G and 17-ATP17-0067, and by a Cottrell Scholar Award from the Research Corporation for Science Advancement. Numerical calculations were run on the Caltech compute cluster 'Wheeler,' allocations from XSEDE TG-AST130039 and PRAC NSF.1713353 supported by the NSF, and NASA HEC SMD-16-7592.

Attached Files

Published - stz2887.pdf

Submitted - 1812.02749.pdf

Files

stz2887.pdf
Files (8.4 MB)
Name Size Download all
md5:ce7f17636321e4b8b0a05f41c79026a2
3.9 MB Preview Download
md5:cf0bef721a71e3d9abf69c5ceb8608be
4.5 MB Preview Download

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023