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Testing the Relationship between Bursty Star Formation and Size Fluctuations of Local Dwarf Galaxies

Emami, Najmeh and Siana, Brian and El-Badry, Kareem and Cook, David and Ma, Xiangcheng and Weisz, Daniel and Gharibshah, Joobin and Alaee, Sara and Scarlata, Claudia and Skillman, Evan (2021) Testing the Relationship between Bursty Star Formation and Size Fluctuations of Local Dwarf Galaxies. Astrophysical Journal, 922 (2). Art. No. 217. ISSN 0004-637X. doi:10.3847/1538-4357/ac1f8d.

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Stellar feedback in dwarf galaxies plays a critical role in regulating star formation via galaxy-scale winds. Recent hydrodynamical zoom-in simulations of dwarf galaxies predict that the periodic outward flow of gas can change the gravitational potential sufficiently to cause radial migration of stars. To test the effect of bursty star formation on stellar migration, we examine star formation observables and sizes of 86 local dwarf galaxies. We find a correlation between the R-band half-light radius (R_e) and far-UV luminosity (L_(FUV)) for stellar masses below 10⁸ M⊙ and a weak correlation between the R_e and Hα luminosity (L_(Hα)). We produce mock observations of eight low-mass galaxies from the FIRE-2 cosmological simulations and measure the similarity of the time sequences of R_e and a number of star formation indicators with different timescales. Major episodes of R_e time sequence align very well with the major episodes of star formation, with a delay of ∼50 Myr. This correlation decreases toward star formation rate indicators of shorter timescales such that R_e is weakly correlated with L_(FUV) (10–100 Myr timescale) and is completely uncorrelated with L_(Hα) (a few Myr timescale), in agreement with the observations. Our findings based on FIRE-2 suggest that the R-band size of a galaxy reacts to star formation variations on a ∼50 Myr timescale. With the advent of a new generation of large space telescopes (e.g., JWST), this effect can be examined explicitly in galaxies at higher redshifts, where bursty star formation is more prominent.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Emami, Najmeh0000-0003-2047-1689
Siana, Brian0000-0002-4935-9511
El-Badry, Kareem0000-0002-6871-1752
Cook, David0000-0002-6877-7655
Ma, Xiangcheng0000-0001-8091-2349
Weisz, Daniel0000-0002-6442-6030
Alaee, Sara0000-0001-5870-4025
Scarlata, Claudia0000-0002-9136-8876
Skillman, Evan0000-0003-0605-8732
Additional Information:© 2021. The American Astronomical Society. Received 2021 June 4; revised 2021 August 12; accepted 2021 August 18; published 2021 December 1. We thank the anonymous referee for providing constructive comments that helped improve the quality of this paper. We also thank T. K. Chan and Amanda Pagul for their helpful discussions. This material is based on work supported by UC Riverside Overhead Return Grant under grant No. A01868-19900-40-FPBS.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
University of California, RiversideA01868-19900-40-FPBS
Subject Keywords:Dwarf galaxies; Galaxy kinematics; Galaxy dynamics; Star formation; Galaxy evolution
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Dwarf galaxies (416); Galaxy kinematics (602); Galaxy dynamics (591); Star formation (1569); Galaxy evolution (594)
Record Number:CaltechAUTHORS:20211221-866893000
Persistent URL:
Official Citation:Najmeh Emami et al 2021 ApJ 922 217
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112620
Deposited By: George Porter
Deposited On:21 Dec 2021 22:27
Last Modified:25 Jul 2022 23:15

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