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Galaxy And Mass Assembly (GAMA): A forensic SED reconstruction of the cosmic star-formation history and metallicity evolution by galaxy type

Bellstedt, S, Robotham, ASG, Driver, SP, Thorne, JE, Davies, LJM, Lagos, CDP, Stevens, ARH, Taylor, EN, Baldry, IK, Moffett, AJ, Hopkins, AM and Phillipps, S (2020) Galaxy And Mass Assembly (GAMA): A forensic SED reconstruction of the cosmic star-formation history and metallicity evolution by galaxy type. Monthly Notices of the Royal Astronomical Society, 498 (4). pp. 5581-5603. ISSN 0035-8711

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Abstract

We apply the spectral energy distribution-fitting code ProSpect to multiwavelength imaging for $\sim$7,000 galaxies from the GAMA survey at $z<0.06$, in order to extract their star-formation histories. We combine a parametric description of the star formation history with a closed-box evolution of metallicity where the present-day gas-phase metallicity of the galaxy is a free parameter. We show with this approach that we are able to recover the observationally-determined cosmic star formation history (CSFH), an indication that stars are being formed in the correct epoch of the Universe, on average, for the manner in which we are conducting SED fitting. We also show the contribution to the CSFH of galaxies of different present-day visual morphologies, and stellar masses. This analysis suggests that half of the mass in present-day elliptical galaxies was in place 11 Gyr ago, whereas in other morphological types the stellar mass formed later, up to 6 Gyr ago for present-day irregular galaxies. Similarly, the most massive galaxies in our sample were shown to have formed half their stellar mass by 10.5 Gyr ago, whereas the least massive galaxies formed half their stellar mass as late as 4 Gyr ago (the well-known effect of "galaxy downsizing"). Finally, our metallicity approach allows us to follow the average evolution in gas-phase metallicity for populations of galaxies, and extract the evolution of the cosmic metal mass density in stars and in gas, producing results in broad agreement with observations of metal densities in the Universe.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2020 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: astro-ph.GA; astro-ph.GA
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 09 Oct 2020 09:47
Last Modified: 09 Oct 2020 10:00
DOI or Identification number: 10.1093/mnras/staa2620
URI: https://researchonline.ljmu.ac.uk/id/eprint/13813

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