Star-formation rate in compact star-forming galaxies

TL;DR

This study estimates the long-term star formation rates in compact star-forming galaxies using multi-wavelength data, revealing that traditional methods overestimate current rates and proposing more accurate relations accounting for galaxy evolution.

Contribution

It introduces new relations for estimating average star formation rates in CSFGs that incorporate their luminosity evolution over time, improving accuracy over traditional methods.

Findings

Average SFR coefficient linking <SFR> and SFR_0 is 0.04.

Traditional SFR estimates are 2-3 times higher than <SFR>.

New relations reduce dispersion and better account for galaxy evolution.

Abstract

We use the data for the Hbeta emission-line, far-ultraviolet (FUV) and mid-infrared 22 micron continuum luminosities to estimate star formation rates <SFR> averaged over the galaxy lifetime for a sample of about 14000 bursting compact star-forming galaxies (CSFGs) selected from the Data Release 12 (DR12) of the Sloan Digital Sky Survey (SDSS). The average coefficient linking <SFR> and the star formation rate SFR_0 derived from the Hbeta luminosity at zero starburst age is found to be 0.04. We compare <SFR>s with some commonly used SFRs which are derived adopting a continuous star formation during a period of ~100 Myr, and find that the latter ones are 2-3 times higher. It is shown that the relations between SFRs derived using a geometric mean of two star-formation indicators in the UV and IR ranges and reduced to zero starburst age have considerably lower dispersion compared to those with single star-formation indicators. We suggest that our relations for <SFR> determination are more appropriate for CSFGs because they take into account a proper temporal evolution of their luminosities. On the other hand, we show that commonly used SFR relations can be applied for approximate estimation within a factor of ~2 of the <SFR> averaged over the lifetime of the bursting compact galaxy.