2022ApJ...928...68S -
Astrophys. J., 928, 68-68 (2022/March-3)
Infrared Spectral Energy Distributions and Dust Masses of Sub-solar Metallicity Galaxies at z ∼ 2.3.
SHIVAEI I., POPPING G., RIEKE G., REDDY N., POPE A., KENNICUTT R., MOBASHER B., COIL A., FUDAMOTO Y., KRIEK M., LYU J., OESCH P., SANDERS R., SHAPLEY A. and SIANA B.
Abstract (from CDS):
We present results from Atacama Large Millimeter/submillimeter Array (ALMA) 1.2 mm continuum observations of a sample of 27 star-forming galaxies at z = 2.1-2.5 from the MOSFIRE Deep Evolution Field survey with metallicity and star formation rate measurements from optical emission lines. Using stacks of Spitzer, Herschel, and ALMA photometry (rest frame ∼8-400 µm), we examine the infrared (IR) spectral energy distributions (SED) of z ∼ 2.3 subsolar-metallicity (∼0.5 Z☉) luminous infrared galaxies (LIRGs). We find that the data agree well with an average template of higher-luminosity local low-metallicity dwarf galaxies (reduced χ2 = 1.8). When compared with the commonly used templates for solar-metallicity local galaxies or high-redshift LIRGs and ultraluminous IR galaxies, even in the most favorable case (with reduced χ2 = 2.8), the templates are rejected at >98% confidence. The broader and hotter IR SED of both the local dwarfs and high-redshift subsolar-metallicity galaxies may result from different grain properties or a harder/more intense ionizing radiation field that increases the dust temperature. The obscured star formation rate (SFR) indicated by the far-IR emission of the subsolar-metallicity galaxies is only ∼60% of the total SFR, considerably lower than that of the local LIRGs with ∼96%-97% obscured fractions. Due to the evolving IR SED shape, the local LIRG templates fit to mid-IR data overestimate the Rayleigh-Jeans tail measurements by a factor of 2-20. These templates underestimate IR luminosities if fit to the observed ALMA fluxes by >0.4 dex. At a given stellar mass or metallicity, dust masses at z ∼ 2.3 are an order of magnitude higher than z ∼ 0. Given the predicted molecular gas fractions, the observed z ∼ 2.3 dust-to-stellar mass ratios suggest lower dust-to-molecular gas masses than in local galaxies with similar metallicities.
Abstract Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Galaxies - Galaxy evolution - Galaxy chemical evolution - Chemical enrichment - Metallicity - Dust continuum emission - Gas-to-dust ratio - Astronomical models - Astrophysical dust processes - High-redshift galaxies - Galactic and extragalactic astronomy - Dwarf galaxies
Simbad objects:
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