Cosmology with Galaxy Photometry Alone

Chang Hoon Hahn, Francisco Villaescusa-Navarro, Peter Melchior, Romain Teyssier

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

We present the first cosmological constraints using only the observed photometry of galaxies. Villaescusa-Navarro et al. recently demonstrated that the internal physical properties of a single simulated galaxy contain a significant amount of cosmological information. These physical properties, however, cannot be directly measured from observations. In this work, we present how we can go beyond theoretical demonstrations to infer cosmological constraints from actual galaxy observables (e.g., optical photometry) using neural density estimation and the CAMELS suite of hydrodynamical simulations. We find that the cosmological information in the photometry of a single galaxy is limited. However, we combine the constraining power of photometry from many galaxies using hierarchical population inference and place significant cosmological constraints. With the observed photometry of ∼20,000 NASA-Sloan Atlas galaxies, we constrain Ω m = 0.323 − 0.095 + 0.075 and σ 8 = 0.799 − 0.085 + 0.088 .

Original languageEnglish (US)
Article numberL18
JournalAstrophysical Journal Letters
Volume966
Issue number1
DOIs
StatePublished - May 1 2024

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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