Millimeter- and submillimeter-wave spectrum of highly excited states of water

Pearson, J. C.; Lucia, Frank C. De; Anderson, Todd; Herbst, Eric; Helminger, Paul

doi:10.1086/186149

Cited by 41 publications

(25 citation statements)

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“…4) which peaks at 2.5 K for p-H 2 O 1 11 -0 00 at the W43 MM1 core position is almost completely absorbed for channels close to the source velocity. But Pearson et al (1991). The rms is the noise at δν = 1.1MHz.…”

Section: Mapping Resultsmentioning

confidence: 98%

Structure and kinematics of the clouds surrounding the Galactic mini-starburst W43 MM1

Jacq

Braine

Herpin

et al. 2016

A&A

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Massive stars have a major influence on their environment yet their formation is difficult to study as they form quickly in highly obscured regions and are rare, hence more distant than lower mass stars. W43 is a highly luminous galactic massive star forming region at a distance of 5.5 kpc and the MM1 part hosts a particularly massive dense core (1000 M ⊙ within 0.05 pc). We present new Herschel HIFI maps of the W43 MM1 region covering the main low-energy water lines at 557, 987, and 1113 GHz, their H 18 2 O counterparts, and other lines such as 13 CO (10-9) and C 18 O (9-8) which trace warm gas. These water lines are, with the exception of line wings, observed in absorption. Herschel SPIRE and JCMT 450 µm data have been used to make a model of the continuum emission at the HIFI wavelengths. Analysis of the maps, and in particular the optical depth maps of each line and feature, shows that a velocity gradient, possibly due to rotation, is present in both the envelope (r > ∼ 0.5 pc) and the protostellar core (r < ∼ 0.2 pc). Velocities increase in both components from SW to NE, following the general source orientation. While the H 2 O lines trace essentially the cool envelope, we show that the envelope cannot account for the H 18 2 O absorption, which traces motions close to the protostar. The core has rapid infall, 2.9 km s −1 , as manifested by the H 18 2 O absorption features which are systematically red-shifted with respect to the 13 CO (10-9) emission line which also traces the inner material with the same angular resolution. Some H 18 2 O absorption is detected outside the central core and thus outside the regions expected (from a spherical model) to be above 100 K-we attribute this to warm gas associated with the other massive dense cores in W43 MM1. Using the maps to identify absorption from cool gas on large scales, we subtract this component to model spectra for the inner envelope. Modeling the new, presumably corrected, spectra results in a lower water abundance, decreased from 8 10 −8 to 8 10 −9 , with no change in infall rate.

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Section: Mapping Resultsmentioning

confidence: 98%

Structure and kinematics of the clouds surrounding the Galactic mini-starburst W43 MM1

Jacq

Braine

Herpin

et al. 2016

A&A

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“…Typical uncertainty in the frequencies is on the order of 100 kHz (Pearson et al 1991). Calibration of the raw data onto T A scale was performed by the in-orbit system (Roelfsema 2010); conversion to T mb was done with a beam efficiency estimated by raster maps of Mars (Table 1, R.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Water in massive star-forming regions: HIFI observations of W3 IRS5

Chavarría

Herpin

Jacq

et al. 2010

A&A

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We present Herschel observations of the water molecule in the massive star-forming region W3 IRS5. lines show absorption from the cold material (T ∼ 10 K) in which the high-mass protostellar envelope is embedded. One-dimensional radiative transfer models are used to estimate water abundances and to further study the kinematics of the region. We show that the emission in the rare isotopologues comes directly from the inner parts of the envelope (T 100 K) where water ices in the dust mantles evaporate and the gas-phase abundance increases. The resulting jump in the water abundance (with a constant inner abundance of 10 −4 ) is needed to reproduce the o-H 17 2 O 1 10 -1 01 and p-H 18 2 O 1 11 -0 00 spectra in our models. We estimate water abundances of 10 −8 to 10 −9 in the outer parts of the envelope (T 100 K). The possibility of two protostellar objects contributing to the emission is discussed.

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“…The microwave transitions included in the data set correspond to rotational transitions within the ground vibrational state [8,[28][29][30][31][32][33][34] and the (0 1 0) state [31,[33][34][35][36][37][38], most of which were analyzed in our previous paper [39]. In addition to these lines, a few transitions within the first triad states [34,40] were considered.…”

Section: The Data Setmentioning

confidence: 99%