The Role of Dust, UV Luminosity and Large-scale Environment on the Escape of Lya Photons: A Case Study of a Protocluster field at z = 3.1

Abstract

We present a detailed characterization of the Lya properties for 93 Lya emitters (LAEs) at z~3.1 selected from the D1 field of the Canada-France-Hawaii-Telescope Legacy Survey, including 24 members of a massive protocluster. The median-stacked Lya image shows an extended Lya halo (LAH) surrounding the galaxy with the exponential scale length 4.9+/-0.7kpc, which accounts for roughly half of the total line flux. Accounting for the LAH contribution, the total Lya escape fraction, f_esc, is 40+/-26%. Combining the dataset with existing measurements, we find a dependence of f_esc on the galaxy's UV slope (beta) and UV luminosity (L_UV). The simultaneous use of both parameters allows prediction of f_esc within 0.18dex, a substantial improvement over 0.23dex when only beta is used. The correlation between f_esc and E(B-V) suggests that Lya photons undergo interstellar dust attenuation in a similar manner to continuum photons. Yet, Lya transmission is typically higher than that expected for continuum photons at similar wavelength by a factor, which depends on UV luminosity, up to 2 in the samples we studied. These results hint at complex geometries and physical conditions of the interstellar medium, which affect the Lya transmission or production. Alternatively, the dust law may change with luminosity leading to over-or under-estimation of f_esc. Finally, we report that protocluster member LAEs tend to be bluer and more UV-luminous than their field cousins, resulting in systematically higher f_esc values. We speculate that it may be due to the widespread formation of young low-mass galaxies in dense gas-rich environments.

27 pages, 12 figures, accepted by ApJ

References in corpus (34)

• Cosmic Star Formation History
• Escape fraction of ionizing photons during reionization: effects due to supernova feedback and runaway OB stars
• A Population of Faint Extended Line Emitters and the Host Galaxies of Optically Thick QSO Absorption Systems
• Lyman-alpha spectral properties of five newly discovered Lyman continuum emitters
• Protoclusters associated with z > 2 radio galaxies. I. Characteristics of high redshift protoclusters
• Observations of the Lyman-$\alpha$ Universe
• Diffuse Lyman-alpha Halos around Galaxies at z=2.2-6.6: Implications for Galaxy Formation and Cosmic Reionization
• The Lyman alpha Reference Sample: Extended Lyman alpha Halos Produced at Low Dust Content
• Lyman alpha Resonant Scattering in Young Galaxies - Predictions from Cosmological Simulations
• On the Detectability of Lyman-alpha Emission in Star-forming Galaxies: The Role of Dust
• The origin of the escape of Lyman alpha and ionizing photons in Lyman Continuum Emitters
• Effects of Dust Geometry in Lyman Alpha Galaxies at z = 4.4
• The CALYMHA survey: Lya luminosity function and global escape fraction of Lya photons at z=2.23
• Lyman-alpha Forest Tomography from Background Galaxies: The First Megaparsec-Resolution Large-Scale Structure Map at z>2
• The HETDEX Pilot Survey V: The Physical Origin of Lyman-alpha Emitters Probed by Near-infrared Spectroscopy
• MMT Spectroscopy of Lyman-alpha at z$\simeq$7: Evidence for Accelerated Reionization Around Massive Galaxies
• The MUSE Hubble Ultra Deep Field Survey X. Ly$\alpha$ Equivalent Widths at $2.9<z<6.6$
• Spitzer Observations of the z=2.73 Lensed Lyman Break Galaxy, MS1512-cB58
• The MUSE Hubble Ultra Deep Field Survey VIII : Extended Lyman-alpha haloes around high-redshift star-forming galaxies
• A Comprehensive Study of Ly$\alpha$ Emission in the High-redshift Galaxy Population
• Discovery of a Very Large Structure at Z=3.78
• On the Diffuse Lyman-alpha Halo Around Lyman-alpha Emitting Galaxies
• The Diversity of Diffuse Ly$\alpha$ Nebulae around Star-Forming Galaxies at High Redshift
• The evolution of rest-frame UV properties, Lya EWs and the SFR-Stellar mass relation at z~2-6 for SC4K LAEs
• Discovery of a Proto-cluster Associated with a Ly-$\alpha$ Blob Pair at z=2.3
• The Stellar Mass, Star Formation Rate and Dark Matter Halo Properties of LAEs at $z\sim 2$
• How Do Galaxies trace a large scale structure?: A case study around a massive protocluster at $z=3.13$
• Accelerated galaxy growth and environmental quenching in a protocluster at z=3.24
• A detailed study of massive galaxies in a protocluster at z=3.13
• Statistical correlation between the distribution of Ly$\alpha$ emitters and IGM HI at $z\sim 2.2$ mapped by Subaru/Hyper Suprime-Cam
• The Importance Of Star Formation Intensity In LYα Escape From Green Pea Galaxies And Lyman Break Galaxy Analogs
• First Infrared-based implications for the dust attenuation and star formation of typical Ly$\alpha$ emitters
• Differences and similarities of stellar populations in LAEs and LBGs at $z\sim$ 3.4 - 6.8
• The HETDEX Survey: The Ly$\alpha$ Escape Fraction from 3D-HST Emission Line Galaxies at $z\sim 2$

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