The HST GOALS Survey: Probing the Morphology and Evolution of (U)LIRGs
Sebastian Haan (CSIRO Astronomy & Space Science)
Luminous and Ultraluminous Infrared Galaxies (U/LIRGs) represent a key stage in galaxy evolution and provide a perfect laboratory to test the environment of extreme starbursts and the impact of major mergers on galaxy formation. The Great Observatories All-sky LIRG Survey (GOALS) combines high-resolution multiwavelength Hubble Space Telescope observations with mid-IR and far-IR diagnostics (Spitzer, Herschel) for a complete sample of (U)LIRGs in the local Universe. Our study of the nuclear stellar structure in the 85 most luminous U/LIRGs of the GOALS sample revealed that most U/LIRGs exhibit nuclear stellar cusps which are measured as a resolved central excess light component in the stellar light profiles. Here we compare for the first time the cusp and core properties in the few remaining gas-rich major mergers still present in the local Universe to those of present-day core and cusp-dominated ellipticals as tracer of their evolutionary link age. Moreover, we find that the nuclear stellar structure becomes significant more compact with far-IR luminosity and merger stage, which can be associated with the build-up of nuclear stellar cusps and might explain the dramatic increase of nuclear compactness as observed in high-redshift galaxies (e.g. CANDELS survey).