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arXiv · 2402.00935

pop-cosmos: A comprehensive picture of the galaxy population from COSMOS data

Justin Alsing·Stephen Thorp·Sinan Deger·Hiranya Peiris·Boris Leistedt·Daniel Mortlock·Joel Leja
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Abstract

We present pop-cosmos: a comprehensive model characterizing the galaxy population, calibrated to $140,938$ ($r<25$ selected) galaxies from the Cosmic Evolution Survey (COSMOS) with photometry in $26$ bands from the ultra-violet to the infra-red. We construct a detailed forward model for the COSMOS data, comprising: a population model describing the joint distribution of galaxy characteristics and its evolution (parameterized by a flexible score-based diffusion model); a state-of-the-art stellar population synthesis (SPS) model connecting galaxies' instrinsic properties to their photometry; and a data-model for the observation, calibration and selection processes. By minimizing the optimal transport distance between synthetic and real data we are able to jointly fit the population- and data-models, leading to robustly calibrated population-level inferences that account for parameter degeneracies, photometric noise and calibration, and selection. We present a number of key predictions from our model of interest for cosmology and galaxy evolution, including the mass function and redshift distribution; the mass-metallicity-redshift and fundamental metallicity relations; the star-forming sequence; the relation between dust attenuation and stellar mass, star formation rate and attenuation-law index; and the relation between gas-ionization and star formation. Our model encodes a comprehensive picture of galaxy evolution that faithfully predicts galaxy colors across a broad redshift ($z<4$) and wavelength range.

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Justin Alsing, Stephen Thorp, Sinan Deger, Hiranya Peiris, Boris Leistedt, Daniel Mortlock, Joel Leja. 2024-02-01. pop-cosmos: A comprehensive picture of the galaxy population from COSMOS data. https://doi.org/10.3847/1538-4365/ad5c69

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