We propose to survey CO spectral line energy distribution (SLED), from J=4-3 up to J=13-12, on 93 local luminous infrared galaxies (LIRGs; L_{IR} > 1.0E11 L_{sun}) with Herschel SPIRE FTS spectrometer. These galaxies, plus 32 additional LIRGs that will have similar data from existing Herschel programs (mainly the HerCULES project), form a flux-limited subset of the Great Observatories All-Sky LIRGs Survey (GOALS) sample. Our proposal is built on the legacy of GOALS and extends beyond the existing Herschel HerCULES program, which emphasizes more on ULIRGs, to a much needed sample coverage of the more numerous and diverse population of less luminous LIRGs. The data from the proposed observations will not only provide much needed local LIRG templates for future ALMA studies of high-redshift counterparts, but also lend us a powerful diagnostic tool to probe the warm and dense molecular gas that are more closely related to the starburst or AGN activity in the nuclei of LIRGs. The data from this proposal will provide important statistical clues to the interplay between the cold and warm molecular gas, IR luminosity, star formation rate and efficiency, and the diverse properties of LIRGs. Specifically, using the homogeneous CO SLED data from this proposal, together with ground-base, low-order CO line data (mainly J=1-0) and other data that have been compiled for the GOALS sample, we will address the following questions: (1) What is the dominant nuclear power source in individual sample galaxy: starburst or AGN? (2) What are the typical physical properties of warm molecular gas in the nuclei of LIRGs? (3) How do the nuclear warm gas components correlate to the cold gas component, star formation rate and efficiency, dust temperature, etc? and (4) How does molecular gas excitation change along a merger sequence?
Publication
On the far-infrared metallicity diagnostics: applications to high-redshift galaxies . Rigopoulou D. et al. . Monthly Notices of the Royal Astronomical Society, Volume 473, Issue 1, p.20-29 . 473 . 10.1093/mnras/stx2311 . 2018MNRAS.473...20R , The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder - II. Estimating radial velocity of SPIRE spectral observation sources . Scott Jeremy P. et al. . Monthly Notices of the Royal Astronomical Society . null . null . 2020MNRAS.496.4894S , A Herschel-PACS Far-infrared Line Emission Survey of Local Luminous Infrared Galaxies . Díaz-Santos T. et al. . The Astrophysical Journal, Volume 846, Issue 1, article id. 32, 22 pp. (2017). . 846 . 10.3847/1538-4357/aa81d7 . 2017ApJ...846...32D , Warm Molecular Gas in Luminous Infrared Galaxies . Lu N. et al. . The Astrophysical Journal Letters, Volume 787, Issue 2, article id. L23, 5 pp. (2014). . 787 . 10.1088/2041-8205/787/2/L23 . 2014ApJ...787L..23L , The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder - III. Line identification and off-axis spectra . Benson Chris S. et al. . Monthly Notices of the Royal Astronomical Society . null . null . 2020MNRAS.496.4906B , Stacked Average Far-infrared Spectrum of Dusty Star-forming Galaxies from the Herschel-SPIRE Fourier Transform Spectrometer . Wilson Derek et al. . The Astrophysical Journal, Volume 848, Issue 1, article id. 30, 31 pp. (2017). . 848 . 10.3847/1538-4357/aa8cc7 . 2017ApJ...848...30W , Measuring Star Formation Rate and Far-infrared Color in High-redshift Galaxies Using the CO(7-6) and [N II] 205 μm Line...s . Lu Nanyao et al. . The Astrophysical Journal Letters, Volume 802, Issue 1, article id. L11, 6 pp. (2015). . 802 . 10.1088/2041-8205/802/1/L11 . 2015ApJ...802L..11L , L‧CO-LFIR Relations with CO Rotational Ladders of Galaxies Across the Herschel SPIRE Archive . Kamenetzky J. et al. . The Astrophysical Journal, Volume 829, Issue 2, article id. 93, 16 pp. (2016). . 829 . 10.3847/0004-637X/829/2/93 . 2016ApJ...829...93K , The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder I. The Spectral Feature Finder and Catalogue . Hopwood R. et al. . Monthly Notices of the Royal Astronomical Society . null . null . 2020MNRAS.496.4874H , An ACA Survey of [C I] 3<->P1<->-3<->P0<->, CO J = 4 - 3, and Dust Continuum in Nearby U-LIRGs . Michiyama Tomonari et al. . The Astrophysical Journal Supplement Series . null . null . 2021ApJS..257...28M , A Herschel Space Observatory Spectral Line Survey of Local Luminous Infrared Galaxies from 194 to 671 Microns . Lu Nanyao et al. . The Astrophysical Journal Supplement Series, Volume 230, Issue 1, article id. 1, 34 pp. (2017). . 230 . 10.3847/1538-4365/aa6476 . 2017ApJS..230....1L , The [NII] 205 μm Emission in Local Luminous Infrared Galaxies . Zhao Yinghe et al. . The Astrophysical Journal, Volume 819, Issue 1, article id. 69, 16 pp. (2016). . 819 . 10.3847/0004-637X/819/1/69 . 2016ApJ...819...69Z , High-J CO versus Far-infrared Relations in Normal and Starburst Galaxies . Liu Daizhong et al. . The Astrophysical Journal Letters, Volume 810, Issue 2, article id. L14, 6 pp. (2015). . 810 . 10.1088/2041-8205/810/2/L14 . 2015ApJ...810L..14L , A Herschel Survey of the [N II] 205 μm Line in Local Luminous Infrared Galaxies: The [N II] 205 μm Emission as a Star Formation Rate Indicator . Zhao Yinghe et al. . The Astrophysical Journal Letters, Volume 765, Issue 1, article id. L13, 6 pp. (2013). . 765 . 10.1088/2041-8205/765/1/L13 . 2013ApJ...765L..13Z ,
Instrument
SPIRE_SpireSpectrometer_
Temporal Coverage
2011-01-06T08:37:22Z/2012-12-17T13:12:49Z
Version
SPG v14.1.0
Mission Description
Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
