The PAU Survey: Galaxy stellar population properties estimates with narrowband data

Abstract

A newfound interest has been seen in narrowband galaxy surveys as a promising method for achieving the necessary accuracy on the photometric redshift estimate of individual galaxies for next-generation stage IV cosmological surveys. One key advantage is the ability to provide higher spectral resolution information on galaxies, which ought to allow for a more accurate and precise estimation of the stellar population properties for galaxies. However, the impact of adding narrowband photometry on the stellar population properties estimate is largely unexplored. The scope of this work is two-fold: 1) we leverage the predictive power of broadband and narrowband data to infer galaxy physical properties, such as stellar masses, ages, star formation rates, and metallicities; and 2) we evaluate the improvement of performance in estimating galaxy properties when we use narrowband instead of broadband data. In this work, we measured the stellar population properties of a sample of galaxies in the COSMOS field for which both narrowband and broadband data are available. In particular, we employed narrowband data from the Physics of the Accelerating Universe Survey (PAUS) and broadband data from the Canada France Hawaii Telescope legacy survey (CFHTLS). We used two different spectral energy distribution (SED) fitting codes to measure galaxy properties, namely and We find that the increased spectral resolution of narrowband photometry does not yield a substantial improvement in terms of constraining the galaxy properties using the SED fitting. Nonetheless, we find that we are able to obtain a more diverse distribution of metallicities and dust optical depths with when employing the narrowband data. The effect is not as prominent as expected, which we relate to the low narrowband signal-to-noise ratio (S/N) of a majority of the sampled galaxies, the respective drawbacks of both codes, and the restriction of coverage to the optical regime. The measured properties are compared to those reported in the COSMOS2020 catalogue, showing a good agreement. We have released the catalogue of measured properties in tandem with this work.