Green Pea Galaxies and cohorts: Luminous Compact Emission-Line Galaxies
  in the Sloan Digital Sky Survey
  We present a large sample of 803 star-forming luminous compact galaxies
(LCGs) in the redshift range z = 0.02-0.63, selected from Data Release 7 of the
Sloan Digital Sky Survey (SDSS). The global properties of these galaxies are
similar to those of the so-called "green pea" star-forming galaxies, in the
redshift range z=0.112-0.360 and selected from the SDSS on the basis of their
green color and compact structure. In contrast to green pea galaxies, our LCGs
are selected on the basis of both their spectroscopic and photometric
properties, resulting in a ~10 times larger sample, with galaxies spanning a
redshift range >2 times larger. We find that the oxygen abundances and the
heavy element abundance ratios in LCGs do not differ from those of nearby
low-metallicity blue compact dwarf (BCD) galaxies. The median stellar mass of
LCGs is ~1e9 Msun. However, for galaxies with high EW(Hbeta), >100A, it is only
~7x1e8 Msun. The star formation rate in LCGs varies in the large range of
0.7-60 Msun yr^{-1}, with a median value of ~4 Msun yr^{-1}, a factor of ~3
lower than in high-redshift star-forming galaxies at z>3. The specific star
formation rates in LCGs are extremely high and vary in the range ~1e-9 - 1e-7
yr^{-1}, comparable to those derived in high-redshift galaxies.
