A Machine-learning Approach to Predict Missing Flux Densities in Multiband Galaxy Surveys

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Documents

  • Nima Chartab
  • Bahram Mobasher
  • Asantha R. Cooray
  • Shoubaneh Hemmati
  • Zahra Sattari
  • Henry C. Ferguson
  • David B. Sanders
  • John R. Weaver
  • Daniel K. Stern
  • Henry J. McCracken
  • Daniel C. Masters
  • Peter L. Capak
  • Iary Davidzon
  • Mark E. Dickinson
  • Jason Rhodes
  • Andrea Moneti
  • Olivier Ilbert
  • Conor J. R. McPartland
  • Istvan Szapudi
  • Anton M. Koekemoer
  • Harry I. Teplitz
  • Mauro Giavalisco

We present a new method based on information theory to find the optimal number of bands required to measure the physical properties of galaxies with desired accuracy. As a proof of concept, using the recently updated COSMOS catalog (COSMOS2020), we identify the most relevant wave bands for measuring the physical properties of galaxies in a Hawaii Two-0- (H20) and UVISTA-like survey for a sample of i < 25 AB mag galaxies. We find that with the available i-band fluxes, r, u, IRAC/ch2, and z bands provide most of the information regarding the redshift with importance decreasing from r band to z band. We also find that for the same sample, IRAC/ch2, Y, r, and u bands are the most relevant bands in stellar-mass measurements with decreasing order of importance. Investigating the intercorrelation between the bands, we train a model to predict UVISTA observations in near-IR from H20-like observations. We find that magnitudes in the YJH bands can be simulated/predicted with an accuracy of 1 sigma mag scatter less than or similar to 0.2 for galaxies brighter than 24 AB mag in near-IR bands. One should note that these conclusions depend on the selection criteria of the sample. For any new sample of galaxies with a different selection, these results should be remeasured. Our results suggest that in the presence of a limited number of bands, a machine-learning model trained over the population of observed galaxies with extensive spectral coverage outperforms template fitting. Such a machine-learning model maximally comprises the information acquired over available extensive surveys and breaks degeneracies in the parameter space of template fitting inevitable in the presence of a few bands.

Original languageEnglish
Article number91
JournalAstrophysical Journal
Volume942
Issue number2
Number of pages13
ISSN0004-637X
DOIs
Publication statusPublished - 17 Jan 2023

    Research areas

  • PHOTOMETRIC REDSHIFTS, STELLAR, EVOLUTION

ID: 337693608