We have detected the CO(6-5), CO(7-6), and C I 370 Delta *mm lines from the nuclear region of NGC 891 with our submillimeter grating spectrometer ZEUS on the Caltech Submillimeter Observatory. These ...lines provide constraints on photodissociation region (PDR) and shock models that have been invoked to explain the H2 S(0), S(1), and S(2) lines observed with Spitzer. We analyze our data together with the H2 lines, CO(3-2), and infrared continuum from the literature using a combined PDR/shock model. We find that the mid-J CO originates almost entirely from shock-excited warm molecular gas; contributions from PDRs are negligible. Also, almost all of the H2 S(2) line and half of the S(1) line are predicted to emerge from shocks. Shocks with a pre-shock density of 2 X 104 cm--3 and velocities of 10 km s--1 and 20 km s--1 for C-shocks and J-shocks, respectively, provide the best fit. In contrast, the C I line emission arises exclusively from the PDR component, which is best parameterized by a density of 3.2 X 103 cm--3 and a far-ultraviolet field of Go = 100 for both PDR/shock-type combinations. Our mid-J CO observations show that turbulence is a very important heating source in molecular clouds, even in normal quiescent galaxies. The most likely energy sources for the shocks are supernovae or outflows from young stellar objects. The energetics of these shock sources favor C-shock excitation of the lines.
The Tomographic Ionized-Carbon Mapping Experiment (TIME) and TIME-Pilot are proposed imaging spectrometers to measure reionization and large scale structure at redshifts 5–9. We seek to exploit the ...158
μ
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restframe emission of CII, which becomes measurable at 200–300 GHz at reionization redshifts. Here we describe the scientific motivation, give an overview of the proposed instrument, and highlight key technological developments underway to enable these measurements.
We report the results from a systematic search for molecular (OH 119 micron) outflows with Herschel/PACS in a sample of 43 nearby (z < 0.3) galaxy mergers, mostly ultraluminous infrared galaxies ...(ULIRGs) and QSOs. We find that the character of the OH feature (strength of the absorption relative to the emission) correlates with that of the 9.7 micron silicate feature, a measure of obscuration in ULIRGs. Unambiguous evidence for molecular outflows, based on the detection of OH absorption profiles with median velocities more blueshifted than−50 km/s, is seen in 26 (70%) of the 37 OH-detected targets, suggesting a wide-angle (approx. 145 deg.) outflow geometry. Conversely, unambiguous evidence for molecular inflows, based on the detection of OH absorption profiles with median velocities more redshifted than +50 km/s is seen in only four objects, suggesting a planar or filamentary geometry for the inflowing gas. Terminal outflow velocities of approx. −1000 km/s are measured in several objects, but median outflow velocities are typically approx.−200 km/s−1. While the outflow velocities show no statistically significant dependence on the star formation rate, they are distinctly more blueshifted among systems with large active galactic nucleus (AGN) fractions and luminosities log (L(sub AGN)/L(sub solar)) => 11.8 +/- 0.3. The quasars in these systems play a dominant role in driving the molecular outflows. However, the most AGN dominated systems, where OH is seen purely in emission, show relatively modest OH line widths, despite their large AGN luminosities, perhaps indicating that molecular outflows subside once the quasar has cleared a path through the obscuring material.
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