http://arxiv.org/abs/1508.05102
We present a catalog of all CO (J=1-0 through J=13-12), [CI], and [NII] 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 LFIR, L’CO, and LCO/LCO(1-0). We also present a new method for estimating probability distribution functions (PDFs) 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(LFIR) vs. Log(L’CO) are linear for all mid- to high-J CO lines. The mid- to high-J CO luminosity relative to CO J=1-0 increases with increasing LFIR, indicating higher excitement of the molecular gas, though these ratios do not exceed ~ 100. The luminosities relative to CO J=1-0 remain relatively flat from J=6-5 through J=13-12, across many orders of magnitude of LFIR. Qualitative comparisons to current theoretical models do not match these flat SLED shapes, indicating the need for more comprehensive modeling of the excitation processes of warm molecular gas in nearby galaxies.
J. Kamenetzky, N. Rangwala, J. Glenn, et. al.
Mon, 24 Aug 15
41/43
Comments: 16 pages, 4 figures (including appendix), submitted to ApJ
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