Luminous infrared galaxies in the local universe

We study the morphology and star formation properties of 159 local luminous infrared galaxies (LIRGs) using multicolor images from Data Release 2 (DR2) of the Sloan Digital Sky Survey (SDSS). The LIRGs are selected from a cross-correlation analysis between the Infrared Astronomical Satellite (IRAS) survey and SDSS. They are all brighter than 15.9 mag in the r band and below redshift similar to 0.1, and so can be reliably classified morphologically. We find that the fractions of interacting/merging and spiral galaxies are similar to 48% and similar to 40%, respectively. Our results complement and confirm the decline (increase) in the fraction of spiral (interacting/merging) galaxies from z similar to 1 to 0.1, as found by Melbourne et al. About 75% of spiral galaxies in the local LIRGs are barred, indicating that bars may play an important role in triggering star formation rates greater than or similar to 20 M-circle dot yr(-1) in the local universe. Compared with high-redshift LIRGs, local LIRGs have lower specific star formation rates, smaller cold gas fractions, and a narrower range of stellar masses. Local LIRGs appear to be either merging galaxies forming intermediate-mass elliptical galaxies, or spiral galaxies undergoing high star formation activities regulated by bars.