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

Abstract

Stellar feedback in dwarf galaxies plays a critical role in regulating star formation via galaxy-scale winds. Recent hydrodynamical zoom 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 10${}^8$ M${}_{\odot }$ and a weak correlation between the R${}_e$ and H$\alpha$ luminosity (L${}_{H\alpha }$). 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 $\sim$ 50 Myrs. This correlation decreases towards SFR indicators of shorter timescales such that $R_e$ is weakly correlated with L${}_{FUV}$ (10-100 Myr timescale) and is completely uncorrelated with L${}_{H\alpha }$ (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 $\sim 50$ 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.

17 pages, 11 figures, Accepted to ApJ

References in corpus (20)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• An H-alpha Imaging Survey of Galaxies in the Local 11 Mpc Volume
• Evolution of asymptotic giant branch stars I. Updated synthetic TP-AGB models and their basic calibration
• High-resolution mass models of dwarf galaxies from LITTLE THINGS
• Dark matter and cosmic structure
• Feedback and the Structure of Simulated Galaxies at redshift z=2
• Neutral hydrogen in galaxy halos at the peak of the cosmic star formation history
• Virialization of the inner CGM in the FIRE simulations and implications for galaxy discs, star formation and feedback
• The time-scales probed by star formation rate indicators for realistic, bursty star formation histories from the FIRE simulations
• Stochastic modeling of star-formation histories I: the scatter of the star-forming main sequence
• The Distribution of Alpha Elements in Andromeda Dwarf Galaxies
• When the Jeans don't fit: How stellar feedback drives stellar kinematics and complicates dynamical modeling in low-mass galaxies
• The Spitzer Local Volume Legacy (LVL) Global Optical Photometry
• A Relationship Between Stellar Metallicity Gradients and Galaxy Age in Dwarf Galaxies
• UVUDF: UV Luminosity Functions at the cosmic high-noon
• DUSTiNGS III: Distribution of Intermediate-Age and Old Stellar Populations in Disks and Outer Extremities of Dwarf Galaxies
• The Dark Matter Distributions in Low-Mass Disk Galaxies. II. The Inner Density Profiles
• Spatially resolved properties of galaxies from CANDELS+MUSE: Radial extinction profile and insights on quenching

Cited by in corpus (17)

• Public data release of the FIRE-2 cosmological zoom-in simulations of galaxy formation
• What Causes The Formation of Disks and End of Bursty Star Formation?
• Observational constraints on stellar feedback in dwarf galaxies
• Eccentricity evolution of massive black hole binaries from formation to coalescence
• The SAGA Survey. III. A Census of 101 Satellite Systems around Milky Way-mass Galaxies
• The globular clusters and star formation history of the isolated, quiescent ultra-diffuse galaxy DGSAT I
• JADES: comprehensive census of broad-line AGN from Reionization to Cosmic Noon revealed by JWST
• Exploring metallicity-dependent rates of Type Ia supernovae and their impact on galaxy formation
• The SAGA Survey. IV. The Star Formation Properties of 101 Satellite Systems around Milky Way-mass Galaxies
• A spatially resolved analysis of star-formation burstiness by comparing UV and H$\alpha$ in galaxies at z$\sim$1 with UVCANDELS
• The In-situ Origins of Dwarf Stellar Outskirts in FIRE-2
• Testable predictions of outside-in age gradients in dwarf galaxies of all types
• The THESAN-ZOOM project: central starbursts and inside-out quenching govern galaxy sizes in the early Universe
• Bursty Star Formation in Dwarfs is Sensitive to Numerical Choices in Supernova Feedback Models
• Probing bursty star formation by cross-correlating extragalactic background light and galaxy surveys
• Improved Measurements of Galaxy Star Formation Stochasticity from the Intrinsic Scatter of Burst Indicators
• The Formation of Dwarf Galaxy Disks