Compact star-forming galaxies: relations between integrated characteristics of a starburst

Abstract

We study a large sample of compact star-forming galaxies (CSFGs) from the Data Release 14 of the Sloan Digital Sky Survey. The sample includes about 30000 compact isolated galaxies with angular diameters about 6”–10” in the redshift range z = 0–1. The Hb emission lines with equivalent widths EW(Hβ) ³ 10 Å are observed in the spectra of all selected galaxies. Only star-forming galaxies without obvious signatures of an AGN and with well-detected [OIII]l4363 Å were included in the sample. We consider the relations between the extinction- and aperture-corrected star formation rate SFR(Hβ), specific star formation rate sSFR(Hβ) and their respective values, SFR0(Hβ) and sSFR0(Hβ), reduced to a zero starburst age, on the one hand, and the mass of young stellar population with the age < 10 Myr, the age of a starburst, and the oxygen abundance 12+logO/H in the interstellar medium of these galaxies, on the other hand. A tight and almost linear correlation is found between the star formation rate and the mass of the young stellar population, but a weak correlation is revealed between the star formation rate and oxygen abundance. It is shown that the specific star formation rates, with average values ásSFR(Hβ)ñ = 8.8 Gyr-1 and ásSFR0(Hβ)ñ = 28 Gyr-1, do not depend on the mass of the young stellar population and oxygen abundance and therefore are the universal characteristics of compact galaxies with active star formation.