The Astrophysical Journal (Jan 2024)
The Lyα Dependence on Nebular Properties from the HETDEX and MOSDEF Surveys
Abstract
Investigating the impact of galaxy properties on emergent Ly α emission is crucial for reionization studies, given the sensitivity of Ly α to neutral hydrogen. This study presents an analysis of the physical characteristics of 155 star-forming galaxies, 29 with Ly α detected, and 126 with Ly α not detected with Ly α EW 2 σ significance, as determined via a Kolmogorov–Smirnov test. Moreover, there are weaker (≲1 σ significance) indications that the ionization parameter and metallicity differ between the two samples. Our results demonstrate that the escape fraction of Ly α ( ${f}_{\mathrm{esc}}^{\mathrm{Ly}\alpha }$ ) is inversely correlated with stellar mass, star formation rate, and dust attenuation, while it is positively correlated with the ionization parameter, with significance levels exceeding 2 σ . Our findings suggest that the interstellar environments of Ly α -detected galaxies, characterized by low mass, low dust, low gas-phase metallicity, and high ionization parameters, play a pivotal role in promoting the escape of Ly α radiation.
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