The Ly alpha Reference Sample. XIV. Ly alpha Imaging of 45 Low-redshift Star-forming Galaxies and Inferences on Global Emission
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The Ly alpha Reference Sample. XIV. Ly alpha Imaging of 45 Low-redshift Star-forming Galaxies and Inferences on Global Emission. / Melinder, Jens; Ostlin, Goran; Hayes, Matthew; Rasekh, Armin; Mas-Hesse, J. Miguel; Cannon, John M.; Kunth, Daniel; Laursen, Peter; Runnholm, Axel; Herenz, E. Christian; Messa, Matteo; Schaerer, Daniel; Verhamme, Anne; Rivera-Thorsen, T. Emil; Guaita, Lucia; Marquart, Thomas; Puschnig, Johannes; Le Reste, Alexandra; Sandberg, Andreas; Freeland, Emily; Bridge, Joanna.
I: Astrophysical Journal, Supplement Series, Bind 266, Nr. 1, 15, 01.05.2023.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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T1 - The Ly alpha Reference Sample. XIV. Ly alpha Imaging of 45 Low-redshift Star-forming Galaxies and Inferences on Global Emission
AU - Melinder, Jens
AU - Ostlin, Goran
AU - Hayes, Matthew
AU - Rasekh, Armin
AU - Mas-Hesse, J. Miguel
AU - Cannon, John M.
AU - Kunth, Daniel
AU - Laursen, Peter
AU - Runnholm, Axel
AU - Herenz, E. Christian
AU - Messa, Matteo
AU - Schaerer, Daniel
AU - Verhamme, Anne
AU - Rivera-Thorsen, T. Emil
AU - Guaita, Lucia
AU - Marquart, Thomas
AU - Puschnig, Johannes
AU - Le Reste, Alexandra
AU - Sandberg, Andreas
AU - Freeland, Emily
AU - Bridge, Joanna
PY - 2023/5/1
Y1 - 2023/5/1
N2 - We present Ly alpha 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 H alpha equivalent width criteria, but no constraints on Ly alpha luminosity. We employ a pixel stellar continuum fitting code to obtain accurate continuum-subtracted Ly alpha, H alpha, and H beta maps. We find that Ly alpha is less concentrated than FUV and optical line emission in almost all galaxies with significant Ly alpha emission. We present global measurements of Ly alpha and other quantities measured in apertures designed to capture all of the Ly alpha emission. We then show how the escape fraction of Ly alpha 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 Ly alpha 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 Ly alpha luminosity, where the equivalent width of Ly alpha 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 Ly alpha for the galaxies that can be used to find aperture loss fractions at a given physical radius.
AB - We present Ly alpha 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 H alpha equivalent width criteria, but no constraints on Ly alpha luminosity. We employ a pixel stellar continuum fitting code to obtain accurate continuum-subtracted Ly alpha, H alpha, and H beta maps. We find that Ly alpha is less concentrated than FUV and optical line emission in almost all galaxies with significant Ly alpha emission. We present global measurements of Ly alpha and other quantities measured in apertures designed to capture all of the Ly alpha emission. We then show how the escape fraction of Ly alpha 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 Ly alpha 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 Ly alpha luminosity, where the equivalent width of Ly alpha 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 Ly alpha for the galaxies that can be used to find aperture loss fractions at a given physical radius.
KW - HUBBLE-SPACE-TELESCOPE
KW - SIMILAR-TO 2-3
KW - ESCAPE FRACTION
KW - STELLAR POPULATIONS
KW - STARBURST GALAXIES
KW - FORMATION RATES
KW - DUST CONTENT
KW - NEUTRAL ISM
KW - SURVEY. I.
KW - DEEP FIELD
U2 - 10.3847/1538-4365/acc2b8
DO - 10.3847/1538-4365/acc2b8
M3 - Journal article
VL - 266
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 15
ER -
ID: 347790039