CaltechAUTHORS
Published February 2019 | Version Published
Journal Article Open

What drives the evolution of gas kinematics in star-forming galaxies?

Creators

  • 1. ROR icon Manhattan College
  • 2. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 3. ROR icon Swinburne University of Technology
  • 4. ROR icon Centre of Excellence for All-Sky Astrophysics
  • 5. ROR icon The University of Texas at Austin
  • 6. ROR icon Northwestern University
  • 7. ROR icon California Institute of Technology
  • 8. ROR icon University of California, San Diego
  • 9. ROR icon Canadian Institute for Theoretical Astrophysics
  • 10. ROR icon University of California, Davis

Abstract

One important result from recent large integral field spectrograph (IFS) surveys is that the intrinsic velocity dispersion of galaxies traced by star-forming gas increases with redshift. Massive, rotation-dominated discs are already in place at z ∼ 2, but they are dynamically hotter than spiral galaxies in the local Universe. Although several plausible mechanisms for this elevated velocity dispersion (e.g. star formation feedback, elevated gas supply, or more frequent galaxy interactions) have been proposed, the fundamental driver of the velocity dispersion enhancement at high redshift remains unclear. We investigate the origin of this kinematic evolution using a suite of cosmological simulations from the FIRE (Feedback In Realistic Environments) project. Although IFS surveys generally cover a wider range of stellar masses than in these simulations, the simulated galaxies show trends between intrinsic velocity dispersion (σ_(intr)), SFR, and z in agreement with observations. In both observations and simulations, galaxies on the star-forming main sequence have median σ_(intr) values that increase from z ∼ 0 to z ∼ 1–1.5, but this increasing trend is less evident at higher redshift. In the FIRE simulations, σ_(intr) can vary significantly on time-scales of ≲100. These variations closely mirror the time evolution of the SFR and gas inflow rate (⁠M_(gas)⁠). By cross-correlating pairs of σ_(intr), M_(gas)⁠, and SFR, we show that increased gas inflow leads to subsequent enhanced star formation, and enhancements in σ_(intr) tend to temporally coincide with increases in M_(gas) and SFR.

Additional Information

© 2018 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 2018 October 29. Received 2018 October 22; in original form 2018 June 11. Published: 03 November 2018. We thank J. Stott, M. Swinbank, C. Mason, O. Turner, and N. Leethochawalit for kindly sharing their measurements of galaxy properties. We thank the referee for her/his constructive comments that have helped us to improve the quality of this paper. C-LH acknowledges support from the Harlan J. Smith Fellowship at the University of Texas at Austin. The Flatiron Institute is supported by the Simons Foundation. TY acknowledges fellowship support from the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. CAFG was supported by NSF through grants AST-1412836, AST-1517491, AST-1715216, and CAREER award AST-1652522, by NASA through grant NNX15AB22G, and by a Cottrell Scholar Award from the Research Corporation for Science Advancement. Support for PFH was provided by an Alfred P. Sloan Research Fellowship, NASA ATP Grant NNX14AH35G, and NSF Collaborative Research Grant #1411920 and CAREER grant #1455342. DK was supported by NSF grant AST-1715101 and the Cottrell Scholar Award from the Research Corporation for Science Advancement. AW was supported by NASA through grants HST-GO-14734 and HST-AR-15057 from STScI. The numerical calculations were run on the Caltech compute cluster 'Zwicky' (NSF MRI award #PHY-0960291), allocations TG-AST120025 and TG-AST130039 granted by the Extreme Science and Engineering Discovery Environment (XSEDE) supported by the NSF, and allocation PRAC NSF.1713353 supported by the NSF. The authors acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing HPC resources that have contributed to the research results reported within this paper. URL: http://www.tacc.utexas.edu.

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Additional details

Identifiers

Eprint ID
94704
Resolver ID
CaltechAUTHORS:20190415-103759070

Funding

University of Texas at Austin
Simons Foundation
Australian Research Council
CE170100013
NSF
AST-1412836
NSF
AST-1517491
NSF
AST-1715216
NSF
AST-1652522
NASA
NNX15AB22G
Cottrell Scholar of Research Corporation
Alfred P. Sloan Foundation
NASA
NNX14AH35G
NSF
AST-1411920
NSF
AST-1455342
NSF
AST-1715101
NASA
HST-GO-14734
NASA
HST-AR-15057
NSF
PHY-0960291
NSF
TG-AST120025
NSF
TG-AST130039
NSF
OAC-1713353

Dates

Created
2019-04-16
Created from EPrint's datestamp field
Updated
2021-11-16
Created from EPrint's last_modified field

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Caltech groups
TAPIR , Astronomy Department