2006ApJ...649..722W

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 ∼0.1, and so can be reliably classified morphologically. We find that the fractions of interacting/merging and spiral galaxies are ∼48% and ∼40%, respectively. Our results complement and confirm the decline (increase) in the fraction of spiral (interacting/merging) galaxies from z∼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 ≳20 M_☉/yr 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.