Exploring the Correlation between $\mathrm{H}\alpha$-to-UV Ratio and Burstiness for Typical Star-forming Galaxies at $z\sim 2$

Abstract

The $\mathrm{H}\alpha$-to-UV luminosity ratio ($L(\mathrm{H}\alpha )/L(\mathrm{UV})$) is often used to probe SFHs of star-forming galaxies and it is important to validate it against other proxies for burstiness. To address this issue, we present a statistical analysis of the resolved distribution of ${\Sigma }_{\mathrm{SFR}}$ as well as stellar age and their correlations with the globally measured $L(\mathrm{H}\alpha )/L(\mathrm{UV})$ for a sample of 310 star-forming galaxies in two redshift bins of $1.37<z<1.70$ and $2.09<z<2.61$ observed by the MOSDEF survey. We use the multi-waveband CANDELS/3D-HST imaging of MOSDEF galaxies to construct ${\Sigma }_{\mathrm{SFR}}$ and stellar age maps. We analyze the composite rest-frame far-UV spectra of a subsample of MOSDEF targets obtained by the Keck/LRIS, which includes 124 star-forming galaxies (MOSDEF-LRIS) at redshifts $1.4<z<2.6$, to examine the average stellar population properties, and the strength of age-sensitive FUV spectral features in bins of $L(\mathrm{H}\alpha )/L(\mathrm{UV})$. Our results show no significant evidence that individual galaxies with higher $L(\mathrm{H}\alpha )/L(\mathrm{UV})$ are undergoing a burst of star formation based on the resolved distribution of ${\Sigma }_{\mathrm{SFR}}$ of individual star-forming galaxies. We segregate the sample into subsets with low and high $L(\mathrm{H}\alpha )/L(\mathrm{UV})$. The high-$L(\mathrm{H}\alpha )/L(\mathrm{UV})$ subset exhibits, on average, an age of $\log [Age/yr]$ = 8.0, compared to $\log [Age/yr]$ = 8.4 for the low-$L(\mathrm{H}\alpha )/L(\mathrm{UV})$ galaxies, though the difference in age is significant at only the $2\sigma$ level. Furthermore, we find no variation in the strengths of Siiv$\lambda \lambda 1393,1402$ and Civ$\lambda \lambda 1548,1550$ P-Cygni features from massive stars between the two subsamples.

16 pages, 10 figures, published by the Monthly Notices of the Royal Astronomical Society

References in corpus (45)

• Cosmic Star Formation History
• Star Formation in AEGIS Field Galaxies since z=1.1 : The Dominance of Gradually Declining Star Formation, and the Main Sequence of Star-Forming Galaxies
• UV Star Formation Rates in the Local Universe
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• Physical Properties of Wolf-Rayet Stars
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• The MOSFIRE Deep Evolution Field (MOSDEF) Survey: Rest-Frame Optical Spectroscopy for ~1500 H-Selected Galaxies at 1.37 < z < 3.8
• H-alpha Observations of a Large Sample of Galaxies at z~2: Implications for Star Formation in High Redshift Galaxies
• Modelling the nebular emission from primeval to present-day star-forming galaxies
• The Universal Relation of Galactic Chemical Evolution: The Origin of the Mass-Metallicity Relation
• The Direct Detection of Lyman-Continuum Emission from Star-forming Galaxies at z~3
• The Metallicity of Galaxy Disks: Infall versus Outflow
• Binary star progenitors of long gamma-ray bursts
• Ultraviolet spectra of extreme nearby star-forming regions --- approaching a local reference sample for JWST
• Geometry of Star-Forming Galaxies from SDSS, 3D-HST and CANDELS
• New Constraints on the Lyman Continuum Escape Fraction at z~1.3
• The MOSDEF Survey: Optical AGN Diagnostics at z~2.3
• Converting H$\alpha$ Luminosities into Star Formation Rates
• A Multiwavelength Consensus on the Main Sequence of Star-Forming Galaxies at z~2
• X-ray binaries as the origin of nebular HeII emission in low-metallicity star-forming galaxies
• Diverging UV and Halpha fluxes of star forming galaxies predicted by the IGIMF theory
• SLUG - Stochastically Lighting Up Galaxies. II: Quantifying the Effects of Stochasticity on Star Formation Rate Indicators
• The MOSDEF Survey: the Variation of the Dust Attenuation Curve with Metallicity
• X-rays across the galaxy population I: tracing the main sequence of star formation
• On the Similarity between Cluster and Galactic Stellar Initial Mass Functions
• Stochastic modeling of star-formation histories I: the scatter of the star-forming main sequence
• The MOSDEF survey: AGN multi-wavelength identification, selection biases and host galaxy properties
• The H alpha Galaxy Survey. VIII. Close companions and interactions, and the definition of starbursts
• Tracing the Mass-Dependent Star Formation History of Late-Type Galaxies using X-ray Emission: Results from the Chandra Deep Fields
• The Star Formation Burstiness and Ionizing Efficiency of Low-mass Galaxies
• Metallicity dependence of HMXB populations
• Exploring HeII$\lambda$1640 emission line properties at $z\sim 2-4$
• The VANDELS survey: the relation between UV continuum slope and stellar metallicity in star-forming galaxies at z~3
• Narrow He II emission in star-forming galaxies at low metallicity. Stellar wind emission from a population of Very Massive Stars
• A fundamental test for stellar feedback recipes in galaxy simulations
• Star Formation Stochasticity Measured from the Distribution of Burst Indicators
• Looking for Population III stars with He II line intensity mapping
• Kpc-scale Properties of Emission-line Galaxies
• Boosting Lya and HeII 1640A Line Fluxes from Pop III Galaxies: Stochastic IMF Sampling and Departures from Case-B
• Spatially resolved properties of galaxies from CANDELS+MUSE: Radial extinction profile and insights on quenching
• The MOSDEF Survey: An Improved Voronoi Binning Technique on Spatially Resolved Stellar Populations at z~2
• The MOSDEF Survey: The Dependence of H$\alpha$-to-UV SFR Ratios on SFR and Size at $z\sim 2$
• A Multi-Wavelength Study of Star Formation in 15 Local Star-Forming Galaxies
• Improved Measurements of Galaxy Star Formation Stochasticity from the Intrinsic Scatter of Burst Indicators
• The MOSDEF Survey: Probing Resolved Stellar Populations at $z\sim 2$ Using a New Bayesian-defined Morphology Metric Called Patchiness

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