A spatially resolved analysis of star-formation burstiness by comparing UV and H$\alpha$ in galaxies at z$\sim$1 with UVCANDELS

Abstract

The UltraViolet imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) program provides HST/UVIS F275W imaging for four CANDELS fields. We combine this UV imaging with existing HST/near-IR grism spectroscopy from 3D-HST$+$AGHAST to directly compare the resolved rest-frame UV and H$\alpha$ emission for a sample of 979 galaxies at $0.7<z<1.5$ spanning a range in stellar mass of $10^{8-11.5}$ M${}_{\odot }$. Using a stacking analysis, we perform a resolved comparison between homogenized maps of rest-UV and H$\alpha$ to compute the average UV-to-H$\alpha$ luminosity ratio (an indicator of burstiness in star-formation) as a function of galactocentric radius. We find that galaxies below stellar mass of $\sim$10${}^{9.5}$ M${}_{\odot }$, at all radii, have a UV-to-H$\alpha$ ratio higher than the equilibrium value expected from constant star-formation, indicating a significant contribution from bursty star-formation. Even for galaxies with stellar mass $\gtrsim$10${}^{9.5}$ M${}_{\odot }$, the UV-to-H$\alpha$ ratio is elevated towards in their outskirts ($R/R_{eff}>1.5$), suggesting that bursty star-formation is likely prevalent in the outskirts of even the most massive galaxies but is likely over-shadowed by their brighter cores. Furthermore, we present the UV-to-H$\alpha$ ratio as a function of galaxy surface brightness, a proxy for stellar mass surface density, and find that regions below $\sim$10${}^{7.5}$ M${}_{\odot }$ kpc${}^{-2}$ are consistent with bursty star-formation, regardless of their galaxy stellar mass, potentially suggesting that local star-formation is independent of global galaxy properties at the smallest scales. Lastly, we find galaxies at $z>1.1$ to have bursty star-formation regardless of radius or surface brightness.

22 pages, 10 figures; accepted to ApJ

References in corpus (29)

• 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
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• Strong Nebular Line Ratios in the Spectra of z~2-3 Star-forming Galaxies: First Results from KBSS-MOSFIRE
• Nebular Emission Line Ratios in z~2-3 Star-Forming Galaxies with KBSS-MOSFIRE: Exploring the Impact of Ionization, Excitation, and Nitrogen-to-Oxygen Ratio
• Clumpy Galaxies in CANDELS. I. The Definition of UV Clumps and the Fraction of Clumpy Galaxies at 0.5<z<3
• The MOSDEF Survey: Excitation Properties of $z\sim 2.3$ Star-forming Galaxies
• UVUDF: Ultraviolet Through Near-infrared Catalog and Photometric Redshifts of Galaxies in the Hubble Ultra Deep Field
• Non-parametric Star Formation History Reconstruction with Gaussian Processes I: Counting Major Episodes of Star Formation
• Converting H$\alpha$ Luminosities into Star Formation Rates
• Diverging UV and Halpha fluxes of star forming galaxies predicted by the IGIMF theory
• DYNAMO-HST Survey: Clumps in Nearby Massive Turbulent Disks and the Effects of Clump Clustering on Kiloparsec Scale Measurements of Clumps
• Convolution kernels for multi-wavelength imaging
• H-alpha emission in local galaxies: star formation, time variability and the diffuse ionized gas
• The Grism Lens-Amplified Survey from Space (GLASS). II. Gas-phase metallicity and radial gradients in an interacting system at z~2
• ALMA Lensing Cluster Survey: $HST$ and $Spitzer$ Photometry of 33 Lensed Fields Built with CHArGE
• When the Jeans don't fit: How stellar feedback drives stellar kinematics and complicates dynamical modeling in low-mass galaxies
• Early results from GLASS-JWST. IV: Spatially resolved metallicity in a low-mass $z\sim 3$ galaxy with NIRISS
• UVUDF: UV Luminosity Functions at the cosmic high-noon
• Star Formation Stochasticity Measured from the Distribution of Burst Indicators
• Big Fish in Small Ponds: Massive Stars in the Low Mass Clusters of M83
• First Census of Gas-phase Metallicity Gradients of Star-forming Galaxies in Overdense Environments at Cosmic Noon
• Testing the Relationship Between Bursty Star Formation and Size Fluctuations of Local Dwarf Galaxies
• Differential attenuation in star-forming galaxies at 0.3 $\lesssim$ $z$ $\lesssim$ 1.5 in the SHARDS/CANDELS field
• The MOSDEF Survey: The Dependence of H$\alpha$-to-UV SFR Ratios on SFR and Size at $z\sim 2$
• Emission Line Galaxies in the SHARDS Frontier Fields I: Candidate Selection and the Discovery of Bursty Hα Emitters
• Spectroscopically Identified Emission Line Galaxy Pairs in the WISP survey
• Improved Measurements of Galaxy Star Formation Stochasticity from the Intrinsic Scatter of Burst Indicators
• Galaxy Zoo: Clump Scout: Surveying the Local Universe for Giant Star-forming Clumps

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