Abstract
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 a
desired accuracy. As a proof of concept, using the recently updated COSMOS
catalog (COSMOS2020), we identify the most relevant wavebands 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 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 inter-correlation between the bands, we train a
model to predict UVISTA observations in near-IR from H20-like observations. We
find that magnitudes in $YJH$ bands can be simulated/predicted with an accuracy
of $1\sigma$ mag scatter $0.2$ 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.
Description
A Machine Learning Approach to Predict Missing Flux Densities in Multi-band Galaxy Surveys
Links and resources
Tags