The Oxygen Abundances of Luminous and Ultraluminous Infrared Galaxies

Understand

Luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) dominate the star formation rate budget of the universe at z > 1, yet no local measurements of their heavy element abundances exist.

• We measure nuclear or near-nuclear oxygen abundances in a sample of 100 star-forming LIRGs and ULIRGs using new, previously published, and archival spectroscopy of strong emission lines (including [O II] 3727, 3729 A) in galaxies with redshifts <z> ~ 0.1.
• When compared to local emission-line galaxies of similar luminosity and mass (using the near-infrared luminosity-metallicity and mass-metallicity relations), we find that LIRGs and ULIRGs are under-abundant by a factor of two on average.
• As a corollary, LIRGs and ULIRGs also have smaller effective yields.