HSC-CLAUDS survey: The star formation rate functions since z ~ 2 and comparison with hydrodynamical simulations

TL;DR

This paper presents new star formation rate functions up to redshift 2 derived from a novel method using deep imaging data, providing a critical test for galaxy evolution models and comparing observations with simulations.

Contribution

Introduces an original method to estimate SFRs from UV/optical colors, enabling reliable SFR functions across a wide range of SFRs and redshifts up to z=2.

Findings

First SFR functions with reliable high- and low-SFR measurements up to z=2.

Comparison with hydrodynamical simulations highlights agreements and discrepancies.

Demonstrates the effectiveness of the new UV/optical color-based SFR estimation method.

Abstract

Star formation rate functions (SFRFs) give an instantaneous view of the distribution of star formation rates (SFRs) in galaxies at different epochs. They are a complementary and more stringent test for models than the galaxy stellar mass function, which gives an integrated view of the past star formation activity. However, the exploration of SFRFs has been limited thus far due to difficulties in assessing the SFR from observed quantities and probing the SFRF over a wide range of SFRs. We overcome these limitations thanks to an original method that predicts the infrared luminosity from the rest-frame UV/optical color of a galaxy and then its SFR over a wide range of stellar masses and redshifts. We applied this technique to the deep imaging survey HSC-CLAUDS combined with near-infrared and UV photometry. We provide the first SFR functions with reliable measurements in the high- and low-SFR regimes up to $z=2$ and compare our results with previous observations and four state-of-the-art hydrodynamical simulations.