Alonso Herrero, AlmudenaRieke, George H.Rieke, Marcia J.Colina, LuisPérez González, Pablo GuillermoRyder, Stuart D.2023-06-202023-06-202006-10-200004-637X10.1086/506958https://hdl.handle.net/20.500.14352/51941© 2006 The American Astronomical Society. All rights reserved. Based on observations with the NASA/ESA Hubble Space Telescope at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This research has made use of the NASA/ IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA). We thank an anonymous referee for a careful reading of the manuscript and useful suggestions. We would like to thank D. Calzetti and R. Kennicutt for enlightening discussions. We are grateful to T. Hattori for providing us with H images of the galaxies. We thank T. Díaz Santos for helping us with the Spitzer MIPS images of the sample of LIRGs. A. A. H. and L. C. acknowledge support from the Spanish Programa Nacional de Astronomía y Astrofísica under grant AYA2002-01055 and Plan Nacional del Espacio ESP2005-01480, and PGPG from the Spanish Programa Nacional de Astronomía y Astrofísica under grant AYA 2004-01676. This work has been funded by NASA grant HST-GO-10169 and by NASA through contract 1255094 issued by JPL/Caltech.We use Hubble Space Telescope (HST) NICMOS continuum and Paα observations to study the near-infrared and star formation properties of a representative sample of 30 local (d ~ 35-75 Mpc) luminous infrared galaxies (LIRGs, infrared [8-1000 μm] luminosities of log L_IR = 11-11.9 L_☉). The data provide spatial resolutions of 25-50 pc and cover the central ~3.3-7.1 kpc regions of these galaxies. About half of the LIRGs show compact (~1-2 kpc) Paα emission with a high surface brightness in the form of nuclear emission, rings, and minispirals. The rest of the sample show Paα emission along the disk and the spiral arms extending over scales of 3-7 kpc and larger. About half of the sample contains H II regions with Hα luminosities significantly higher than those observed in normal galaxies. There is a linear empirical relationship between the mid-IR 24 μm and hydrogen recombination (extinction-corrected Paα) luminosity for these LIRGs, and the H II regions in the central part of M51. This relation holds over more than four decades in luminosity, suggesting that the mid-IR emission is a good tracer of the star formation rate (SFR). Analogous to the widely used relation between the SFR and total IR luminosity of R. Kennicutt, we derive an empirical calibration of the SFR in terms of the monochromatic 24 μm luminosity that can be used for luminous, dusty galaxies.engjournal articlehttp://dx.doi.org/10.1086/506958http://iopscience.iop.org/open access52Initial mass functionUltraluminous iras galaxiesH-alpha emissionStarburst galaxiesArp 299Optical classificationInteracting galaxiesRecombination-lineSeyfert-galaxiesMerger NGC-3256AstrofísicaAstronomía (Física)