L '(CO)/L-FIR RELATIONS WITH CO ROTATIONAL LADDERS OF GALAXIES ACROSS THE HERSCHEL SPIRE ARCHIVE
AffiliationUniv Arizona, Steward Observ
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PublisherIOP PUBLISHING LTD
CitationL '(CO)/L-FIR RELATIONS WITH CO ROTATIONAL LADDERS OF GALAXIES ACROSS THE HERSCHEL SPIRE ARCHIVE 2016, 829 (2):93 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2016. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractWe present a catalog of all CO (J = 4-3 through J = 13-12), [ C I], and [ N II] lines available from extragalactic spectra from the Herschel SPIRE Fourier Transform Spectrometer (FTS) archive combined with observations of the low-J CO lines from the literature and from the Arizona Radio Observatory. This work examines the relationships between L-FIR, L'(CO), and L-CO/L-CO,L-1-0. We also present a new method for estimating probability distribution functions from marginal signal-to-noise ratio Herschel FTS spectra, which takes into account the instrumental "ringing" and the resulting highly correlated nature of the spectra. The slopes of log(L-FIR) versus log (L'(CO)) are linear for all mid- to high-J CO lines and slightly sublinear if restricted to (ultra) luminous infrared galaxies ((U) LIRGs). The mid-to high-J CO luminosity relative to CO J - 1-0 increases with increasing L-FIR, indicating higher excitement of the molecular gas, although these ratios do not exceed similar to 180. For a given bin in L-FIR, the luminosities relative to CO J = 1-0 remain relatively flat from J = 6-5 through J = 13-12, across three orders of magnitude of L-FIR. A single component theoretical photodissociation region (PDR) model cannot match these flat SLED shapes, although combinations of PDR models with mechanical heating added qualitatively match the shapes, indicating the need for further comprehensive modeling of the excitation processes of warm molecular gas in nearby galaxies.
VersionFinal published version
SponsorsNSF Astronomy and Astrophysics Postdocoral Fellowship [AST-1402193]; NASA [NNX13AL16G]; CSA (Canada); NAOC (China); CEA (France); CNES (France); CNRS (France); ASI (Italy); MCINN (Spain); SNSB (Sweden); STFC (UK); NASA (USA)