A meta-analysis of cosmic star-formation history

TL;DR

This meta-analysis consolidates diverse measurements of cosmic star-formation rate density, confirming a significant decline from redshift unity to today, and quantifies the evolution with a power-law exponent.

Contribution

It provides a comprehensive synthesis of various indicators of star-formation history, establishing the most heterogeneously confirmed trend in galaxy evolution.

Findings

Star-formation rate density decreases significantly from redshift 1 to present.

Best-fit power-law exponent of evolution is approximately 2.7 to 3.3 depending on cosmological model.

Most stellar mass today resides in old populations (>6 Gyr).

Abstract

A meta-analysis is performed of the literature on evolution in cosmic star-formation rate density from redshift unity to the present day. The measurements are extremely diverse, including radio, infrared, and ultraviolet broad-band photometric indicators, and visible and near-ultraviolet line-emission indicators. Although there is large scatter among indicators at any given redshift, virtually all studies find a significant decrease from redshift unity to the present day. This is the most heterogeneously confirmed result in the study of galaxy evolution. When comoving star-formation rate density is treated as being proportional to $(1+z)^{\beta}$, the meta-analysis gives a best-fit exponent and conservative confidence interval of $\beta= 2.7\pm 0.7$ in a world model with $(\Omega_M,\Omega_{\Lambda})=(0.3,0.7)$ and $\beta= 3.3\pm 0.8$ in $(\Omega_M,\Omega_{\Lambda})=(1.0,0.0)$. In either case these evolutionary trends are strong enough that the bulk of the stellar mass at the present day ought to be in old ($>6 \mathrm{Gyr}$) populations.