The Lyα Reference Sample. XIV. Lyα Imaging of 45 Low-redshift Star-forming Galaxies and Inferences on Global Emission

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Fecha
2023-05
Profesor/a Guía
Facultad/escuela
Idioma
en
Título de la revista
ISSN de la revista
Título del volumen
Editor
American Astronomical Society
Nombre de Curso
Licencia CC
CC BY 4.0 Attribution 4.0 International Deed
Licencia CC
https://creativecommons.org/licenses/by/4.0/
Resumen
We present Lyα imaging of 45 low-redshift star-forming galaxies observed with the Hubble Space Telescope. The galaxies have been selected to have moderate to high star formation rates (SFRs) using far-ultraviolet (FUV) luminosity and Hα equivalent width criteria, but no constraints on Lyα luminosity. We employ a pixel stellar continuum fitting code to obtain accurate continuum-subtracted Lyα, Hα, and Hβ maps. We find that Lyα is less concentrated than FUV and optical line emission in almost all galaxies with significant Lyα emission. We present global measurements of Lyα and other quantities measured in apertures designed to capture all of the Lyα emission. We then show how the escape fraction of Lyα relates to a number of other measured quantities (mass, metallicity, star formation, ionization parameter, and extinction). We find that the escape fraction is strongly anticorrelated with nebular and stellar extinction, weakly anticorrelated with stellar mass, but no conclusive evidence for correlations with other quantities. We show that Lyα escape fractions are inconsistent with common dust extinction laws, and discuss how a combination of radiative transfer effects and clumpy dust models can help resolve the discrepancies. We present an SFR calibration based on Lyα luminosity, where the equivalent width of Lyα is used to correct for nonunity escape fraction, and show that this relation provides a reasonably accurate SFR estimate. We also show stacked growth curves of Lyα for the galaxies that can be used to find aperture loss fractions at a given physical radius. © 2023. The Author(s). Published by the American Astronomical Society.
Notas
Indexación: Scopus
Palabras clave
Emission Line Galaxies (459), Galaxies (573), Lyman-alpha Galaxies (978), Starburst Galaxies (1570), Astronomical Methods (1043), Observational Astronomy (1145),
Citación
Astrophysical Journal, Supplement Series. Volume 266, Issue 1. 1 May 2023. Article number 15
DOI
10.3847/1538-4365/acc2b8
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