Ronald L. Snell

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On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass(More)
We analyze the embedded stellar content in the vicinity of the W3/W4/W5 H ii regions using the FCRAO Outer Galaxy 12 CO(1–0) Survey, the IRAS Point Source Catalog, published radio continuum surveys, and new near-infrared and molecular line observations. Thirty-four IRAS Point Sources are identified that have far-infrared colors characteristic of embedded(More)
We report the results of spectroscopic mapping observations carried out toward small (1 ′ × 1 ′) regions within the supernova remnants W44, W28, IC443, and 3C391 using the Infrared Spectrograph of the Spitzer Space Telescope. These observations, covering the 5.2 − 37 µm spectral region, have led to the detection of a total of 15 fine structure transitions(More)
On 4 July 2005 at 5:52 UT the Deep Impact mission successfully completed its goal to hit the nucleus of 9P/Tempel 1 with an impactor, forming a crater on the nucleus and ejecting material into the coma of the comet. NASA's Submillimeter Wave Astronomy Satellite (SWAS) observed the 1 10 −1 01 ortho-water ground-state rotational transition in comet 9P/Tempel(More)
We have used the Submillimeter Wave Astronomy Satellite to map the ground-state 1 10 → 1 01 transition of ortho-H 2 O at 557 GHz in the Orion molecular cloud. H 2 O emission was detected in Orion over an angular extent of about 20 ′ , or nearly 3 pc. The water emission is relatively weak, with line widths (3–6 km s −1) and V LSR velocities (9–11 km s −1)(More)
A summary of global properties and an evaluation of the equilibrium state of molecular regions in the outer Galaxy are presented from the decomposition of the FCRAO Outer Galaxy Survey and targeted 12 CO and 13 CO observations of four giant molecular cloud complexes. The ensemble of identified objects includes both small, isolated clouds and clumps within(More)
We present detections of the ground-state 1 10 → 1 01 transition of ortho-H 2 O at 557 GHz in 18 molecular outflows based on data from the Submillimeter Wave Astronomy Satellite (SWAS). These results are combined with ground-based observations of the J=1-0 transitions of 12 CO and 13 CO obtained at the Five College Radio Astronomy Observatory (FCRAO). Data(More)
We report the detection of interstellar hydrogen deuteride (HD) toward the supernova remnant IC443, and the tentative detection of HD toward the Herbig Haro objects HH54 and HH7 and the star forming region GGD37 (Cepheus A West). Our detections are based upon spectral line mapping observations of the R(3) and R(4) rotational lines of HD, at rest wavelengths(More)
Context. According to traditional gas-phase chemical models, O 2 should be abundant in molecular clouds, but until recently, attempts to detect interstellar O 2 line emission with ground-and space-based observatories have failed. Aims. Following the multi-line detections of O 2 with low abundances in the Orion and ρ Oph A molecular clouds with Herschel, it(More)
We present the first ~7.5'×11.5' velocity-resolved (~0.2 km s(-1)) map of the [C ii] 158 μm line toward the Orion molecular cloud 1 (OMC 1) taken with the Herschel/HIFI instrument. In combination with far-infrared (FIR) photometric images and velocity-resolved maps of the H41α hydrogen recombination and CO J=2-1 lines, this data set provides an(More)