2022MNRAS.511.5730B -
Mon. Not. R. Astron. Soc., 511, 5730-5741 (2022/April-3)
A cautionary tale of Ly C escape fraction estimates from high-redshift galaxies.
BASSETT R., RYAN-WEBER E.V., COOKE J., MESTRIC U., PRICHARD L.J., RAFELSKI M., IWATA I., SAWICKI M., GWYN S. and ARNOUTS S.
Abstract (from CDS):
Measuring the escape fraction, fesc, of ionizing, Lyman continuum (Ly C) radiation is key to our understanding of the process of cosmic reionization. In this paper, we provide a methodology for recovering the posterior probability distribution of the Ly C escape fraction, fescPDF, considering both the observational uncertainties and ensembles of simulated transmission functions through the intergalactic medium (IGM). We present an example of this method applied to a VUDS galaxy at z = 3.64 and find fescPDF = 0.51+0.33–0.34 and compare this to the values computed assuming averaged IGM transmission with and without consideration of detection bias along average sightlines yielding fesc^<T >^ = 1.40+0.80–0.42 and f_ esc_bias = 0.82+0.33–0.16. Our results highlight the limitations of methods assuming average, smooth transmission functions. We also present MOSFIRE data for a sample of seven Ly C candidates selected based on photometric redshifts at z > 3.4, but find that all seven have overestimated photometric redshifts by Δz ∼ 0.2 making them unsuitable for Ly C measurements. This results likely due to a bias induced by our selection criteria.
Abstract Copyright:
© 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
intergalactic medium - galaxies: ISM - dark ages, reionization, first stars
Simbad objects:
9
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