Local luminous infrared galaxies: Spatially resolved mid-infrared observations with Spitzer/IRS



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Alonso Herrero, Almudena and Pereira Santaella, Miguel and Rieke, George H. and Colina, Luis and Engelbracht, Charles W. and Pérez González, Pablo Guillermo and Díaz Santos, Tanio and Smith, J. D. T. (2010) Local luminous infrared galaxies: Spatially resolved mid-infrared observations with Spitzer/IRS. Advances in space research, 45 (1). pp. 99-111. ISSN 0273-1177

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Official URL: http://dx.doi.org/10.1016/j.asr.2009.08.010


Luminous Infrared (IR) Galaxies (LIRGs, L_IR=10^11-10 L_⨀) are an important cosmological class of galaxies as they are the main contributors to the co-moving star formation rate density of the universe at z=1. In this paper we present a guaranteed time observation (GTO) Spitzer InfraRed Spectrograph (IRS) program aimed to obtain spectral mapping of a sample of 14 local d<76Mpc LIRGs. The data cubes map, at least, the central 20arcsec X 20arcsec to 30 arcsec X 30 arcsec regions of the galaxies, and use all four IRS modules covering the full 5-38 μ m spectral range. The final goal of this project is to characterize fully the mid-IR properties of local LIRGs as a first step to understanding their more distant counterparts. In this paper we present the first results of this GTO program. The IRS spectral mapping data allow us to build spectral maps of the bright mid-IR emission lines (e.g., [Ne II] 12.81 μ m, [Ne III]15.56 μ m, [S III] 18.71 μ m, H_2 at 17 μ m), continuum, the 6.2 and 11.3 μ m polycyclic aromatic hydrocarbon (PAH) features, and the 9.7 μ m silicate feature, as well as to extract 1D spectra for regions of interest in each galaxy. The IRS data are used to obtain spatially resolved measurements of the extinction using the 9.7 μ m silicate feature, and to trace star forming regions using the neon lines and the PAH features. We also investigate a number of active galactic nuclei (AGN) indicators, including the presence of high excitation emission lines and a strong dust continuum emission at around 6 9.7 μ m . We finally use the integrated Spitzer/IRS spectra as templates of local LIRGs. We discuss several possible uses for these templates, including the calibration of the star formation rate of IR-bright galaxies at high redshift. We also predict the intensities of the brightest mid-IR emission lines for LIRGs as a function of redshift, and compare them with the expected sensitivities of future space IR missions.

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© 2009 COSPAR. Published by Elsevier Ltd. All rights reserved.
This work was supported by NASA through Contract 1255094 issued by JPL/California Institute of Technology. A.A.-H., M.P.-S., L.C., and T.D.-S. acknowledge support from the Spanish Plan Nacional del Espacio through Grant ESP2007-65475-C02-01. A.A.-H. also acknowledges support from the Spanish Ministry of Science and Innovation through Grant Proyecto Intramural Especial 200850I003.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.

Uncontrolled Keywords:Active galactic nuclei; Polycyclic aromatic-hydrocarbon; Integral field spectroscopy; Dust-obscured galaxies; Extreme star-formation; 8 mu-m; Starburst galaxies; Space-telescope; Spectrograph irs; Arp 299
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:38609
Deposited On:26 Jul 2016 14:37
Last Modified:10 Dec 2018 15:05

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