2015ApJ...800..105G

With a substantial nuclear molecular gas reservoir and broad, high-velocity CO molecular line wings previously interpreted as an outflow, NGC 1266 is a rare SB0 galaxy. Previous analyses of interferometry, spectrally resolved low-J CO emission lines, and unresolved high-J emission lines have established basic properties of the molecular gas and the likely presence of an active galactic nucleus. Here, new spectrally resolved CO J = 5-4 to J = 8-7 lines from Herschel Space Observatory HIFI observations are combined with ground-based observations and high-J Herschel SPIRE observations to decompose the nuclear and putative outflow velocity components and to model the molecular gas to quantify its properties. Details of the modeling and results are described, with comparisons to previous results and exploration of the implications for the gas excitation mechanisms. Among the findings, like for other galaxies, the nuclear and putative outflow molecular gas are well represented by components that are cool (T_nuclear = 6₂¹⁰K and T_outflow∼ 30 K), comprising bulk of the mass (log M_nuclear/M_☉ = 8.3_–0.4^+0.5 and log M_outflow/M_☉ = 7.6_–0.3^+0.3), and the minority of the luminosity (log L_nuclear/L_☉ = 5.44_–0.18^+0.22 and log L_outflow/L_☉∼ 6.5) and warm (T_nuclear = 74_–26⁺¹³⁰ K and T_outflow> 100 K), comprising a minority of the mass (log M_nuclear/ M_☉ = 7.3_–0.5^+0.5 and log M_outflow/M_☉∼ 6.3) but the majority of the luminosity (log L_nuclear/L_☉ = 6.90_–0.16^+0.16 and log L_outflow/L_☉∼ 7.2). The outflow has an anomalously high L_CO/L_FIR of 1.7x10^–3 and is almost certainly shock excited.