The Space Density of Intermediate-redshift, Extremely Compact, Massive Starburst Galaxies

We present a measurement of the intrinsic space density intermediate redshift ($z\sim0.5$), massive ($M_{*} \sim 10^{11} \ \text{M}_{\odot}$), compact ($R_{e} 100$ pc) starburst ($\Sigma_{SFR} 1000 \text{M}_{\odot} \text{yr}^{-1} \text{kpc}^{-1}$) galaxies with tidal features indicative them having undergone recent major mergers. A subset host kiloparsec scale, $>1000 \text{km}\ \text{s}^{-1}$ outflows and have little indication AGN activity, suggesting that extreme star formation can be primary driver large-scale feedback. The aim for this paper is to calculate their so we place in better cosmological context. do by empirically modeling stellar populations massive, galaxies. determine average timescale which recently an nuclear would targeted included our spectroscopically selected sample. find criteria selectable $\sim 148 ^{+27}_{-24}$ Myr $n_{\text{CS}} (1.1^{+0.5}_{-0.3}) \times 10^{-6} \text{Mpc}^{-3}$. This broadly consistent $z\sim0.5$ starbursts being most extremely forming low analogs early Universe as well progenitors fraction post quiescent