# The 1.4 GHz Cosmic Star Formation History at z < 1.3

## TL;DR

This study measures the cosmic star formation history up to redshift 1.3 using deep radio observations, highlighting the importance of sample completeness and luminosity function models in deriving accurate star formation rates.

## Contribution

It provides new measurements of star formation rate density up to z=1.3 using radio data, emphasizing the impact of sample completeness and model assumptions.

## Key findings

- Star formation rate density increases from 0.019 to 0.104 Solar masses per year per Mpc^3 from z=0.225 to z=1.3.
- Radio measurements align within 33% of UV, IR, and 3 GHz data.
- Sample completeness and luminosity function models significantly affect results.

## Abstract

We measure the cosmic star formation history out to z = 1.3 using a sample of 918 radio-selected star forming galaxies within the 2 square degree COSMOS field. To increase our sample size, we combine 1.4 GHz flux densities from the VLA-COSMOS catalogue with flux densities measured from the VLA-COSMOS radio continuum image at the positions of I < 26.5 galaxies, enabling us to detect 1.4 GHz sources as faint as 40 uJy. We find radio measurements of the cosmic star formation history are highly dependent on sample completeness and models used to extrapolate the faint end of the radio luminosity function. For our preferred model of the luminosity function, we find the star formation rate density increases from 0.019 Solar masses per year per cubic Mpc at z = 0.225 to 0.104 Solar masses per year per cubic Mpc, which agrees to within 33% of recent UV, IR and 3 GHz measurements of the cosmic star formation history.