A fundamental plane for field star-forming galaxies
Star formation rate (SFR), metallicity and stellar mass are within the
important parameters of star—forming galaxies that characterize their
formation and evolution. They are known to be related to each other at
low and high redshift in the mass—metallicity, mass—SFR, and
metallicity—SFR relations. In this work we demonstrate the existence of
a plane in the 3D space defined by the axes SFR [log(SFR)(M_sun yr^-1)],
gas metallicity [12+log(O/H)], and stellar mass [log(M_star/M_sun)] of
star-forming galaxies. We used star—forming galaxies from the "main
galaxy sample" of the Sloan Digital Sky Survey—Data Release 7
(SDSS-DR7) in the redshift range 0.04 < z < 0.1 and r-magnitudes
between 14.5 and 17.77. Metallicities, SFRs, and stellar masses were
taken from the Max-Planck-Institute for Astrophysics-John Hopkins
University (MPA-JHU) emission line analysis database. From a final
sample of 44214 galaxies, we find for the first time a fundamental plane
for field galaxies relating the SFR, gas metallicity, and stellar mass
for star—forming galaxies in the local universe. One of the
applications of this plane would be estimating stellar masses from SFR
and metallicity. High redshift data from the literature at redshift ~2.2
and 3.5, do not show evidence for evolution in this fundamental plane.