The Halpha-based Star Formation Rate Density of the Universe at z=0.84

TL;DR

This study measures the star formation rate density at redshift 0.84 using Halpha emission, showing a significant increase compared to lower redshifts and confirming the evolution trend with other tracers.

Contribution

It provides the first Halpha-based measurement of star formation rate density at z=0.84, extending previous low-redshift studies and refining the evolution trend of cosmic star formation.

Findings

Star formation rate density at z=0.84 is 0.17 M_sun/yr/Mpc^3.

The evolution of SFR density follows (1+z)^3.8±0.5.

Results are consistent with other SFR tracers across redshifts.

Abstract

We present the results of an Halpha near-infrared narrow-band survey searching for star-forming galaxies at redshift z=0.84. This work is an extension of our previous narrow-band studies in the optical at lower redshifts. After removal of stars and redshift interlopers (using spectroscopic and photometric redshifts), we build a complete sample of 165 Halpha emitters in the Extended Groth strip and GOODS-N fields with L(Halpha)>10^41 erg/s. We compute the Halpha luminosity function at z=0.84 after corrections for [NII] flux contamination, extinction, systematic errors, and incompleteness. Our sources present an average dust extinction of A(Halpha)=1.5 mag. Adopting Halpha as a surrogate for the instantaneous star formation rate (SFR), we measure a extinction-corrected SFR density of 0.17+-0.03 M_sun/yr/Mpc3. Combining this result to our prior measurements at z=0.02, 0.24, and 0.40, we derive an Halpha-based evolution of the SFR density proportional to (1+z)^beta with beta=3.8+-0.5. This evolution is consistent with that derived by other authors using different SFR tracers.