TY - JOUR
T1 - Local luminous infrared galaxies
T2 - Spatially resolved mid-infrared observations with Spitzer/IRS
AU - Alonso-Herrero, Almudena
AU - Pereira-Santaella, Miguel
AU - Rieke, George H.
AU - Colina, Luis
AU - Engelbracht, Charles W.
AU - Pérez-González, Pablo G.
AU - Díaz-Santos, Tanio
AU - Smith, J. D.T.
N1 - Funding Information:
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 .
PY - 2010/1/4
Y1 - 2010/1/4
N2 - Luminous Infrared (IR) Galaxies (LIRGs, L IR = 10 11 s(-) 10 12 L ȯ ) 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 < 76 Mpc) LIRGs. The data cubes map, at least, the central 20 arcsec × 20 arcsec to 30 arcsec × 30 arcsec regions of the galaxies, and use all four IRS modules covering the full 5 s(-) 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 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.
AB - Luminous Infrared (IR) Galaxies (LIRGs, L IR = 10 11 s(-) 10 12 L ȯ ) 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 < 76 Mpc) LIRGs. The data cubes map, at least, the central 20 arcsec × 20 arcsec to 30 arcsec × 30 arcsec regions of the galaxies, and use all four IRS modules covering the full 5 s(-) 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 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.
KW - Galaxies: Seyfert
KW - Galaxies: evolution
KW - Galaxies: nuclei
KW - Galaxies: structure
KW - Infrared: galaxies
UR - http://www.scopus.com/inward/record.url?scp=71649085633&partnerID=8YFLogxK
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U2 - 10.1016/j.asr.2009.08.010
DO - 10.1016/j.asr.2009.08.010
M3 - Article
AN - SCOPUS:71649085633
SN - 0273-1177
VL - 45
SP - 99
EP - 111
JO - Advances in Space Research
JF - Advances in Space Research
IS - 1
ER -