A meta-analysis of cosmic star-formation history

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 $(1+z)^β$, the meta-analysis gives a best-fit exponent and conservative confidence interval of $β= 2.7\pm 0.7$ in a world model with $(Ω_M,Ω_Λ)=(0.3,0.7)$ and $β= 3.3\pm 0.8$ in $(Ω_M,Ω_Λ)=(1.0,0.0)$. 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.