1998/09/15 by Jason A. Surace, D. B. Sanders · 4 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Extinction (optical mineralogy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Infrared #Luminosity #Luminous infrared galaxy #Quasar #astro-ph
paper · pdf · doi:10.1086/306737
36 pages, 8 figures, includes a special style file replacing a AASTEX file
arxiv created 1998/09/15 · openalex publication_date 1999/02/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We present high spatial resolution (FWHM≈0 3-0 5) H (1.6 μm) and K ' (2.1 μm) images of a complete sample (12) of ultraluminous infrared galaxies (ULIGs) chosen to have "warm" mid-infrared colors ( f 25 / f 60 > 0.2) known to be characteristic of active galaxies. The extended underlying galaxy is detected in each system at H and K ', as are tidal features and many of the star-forming knots seen at optical wavelengths. While some of these knots have considerable near-infrared excesses, we show that they are likely to have bolometric luminosities more similar to those of the extended starbursts with similar optical morphology seen in less far-infrared-luminous interacting systems. We find that each ULIG has increasing contributions at long wavelengths by a very compact source, which we identify as an active galactic nucleus (AGN). We show that the optical/near-infrared colors of these putative nuclei are much more extreme than in the most active starburst IRAS galaxies, yet are identical to those in "far-infrared-loud" quasars, which are in turn similar to optical quasars combined with large quantities of hot (≈800 K) dust. Half of the ULIGs have nuclei with dereddened near-infrared luminosities comparable to those of QSOs, while the other half have dereddened luminosities more similar to Seyfert galaxies, although this may be an effect of patchy extinction and scattering.