Determination of molecular gas properties using methyl cyanide lines

Kalenskii, S. V.; Promislov, V. G.; Alakoz, A. V.; Winnberg, A.; Johansson, Lars

doi:10.1134/1.1320498

Cited by 27 publications

(49 citation statements)

References 27 publications

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“…It is inverted in W3(OH), provided that the source is extended. However, the source is most likely much smaller than our beam (see, e.g., Kalenskii et al 1997) ; in this case the transition is not inverted, and its 6 0 È6~1 E excitation temperature is lower than that of the 5 0 È4 0 E transition.…”

Section: Resultsmentioning

confidence: 99%

“…However, this assumption may not always be valid (see Kalenskii et al 1997). A question arises whether the inversion, found in two lines, can be an artifact, caused by optical depth e †ects.…”

Section: Optical Depth E †Ectsmentioning

confidence: 99%

“…Higher optical depth is not likely, according to Kalenskii et al (1997). Then, using these corrected values, we calculated the transition excitation tem-6~1 È5 0 E perature.…”

Section: Optical Depth E †Ectsmentioning

confidence: 99%

“…The methanol molecule is a slightly asymmetric top with hindered internal rotation and possesses a large number of allowed transitions at radio frequencies. Multitransitional observations can be used to determine the main properties of the ambient gasÈtemperature and densityÈand of the methanol itself (column density and abundance ; Menten et al 1988 ; Kalenskii et al 1997). Ziurys & McGonagle (1993) detected a series of lines near 157 GHz toward Ori-KL.…”

Section: Introductionmentioning

confidence: 99%

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Nonequilibrium Excitation of Methanol in Galactic Molecular Clouds: Multitransitional Observations at 2 Millimeters

Slysh¹,

Kalenskii²,

Вальтц³

et al. 1999

ASTROPHYS J SUPPL S

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We observed 14 methanol transitions near j \ 2 mm in Galactic star-forming regions. Broad, quasithermal methanol lines near 157 GHz were detected toward 73 sources. Together with the J 0 ÈJ~1 E and lines at 133 GHz and the line at 166 GHz, they were used to study 6~1 È5 0 E 5~2 È6~1 E 7 1 È7 0 E the methanol excitation. In the majority of the observed objects, the Class I transition is 6~1 È5 0 E inverted, and the Class II and transitions are overcooled. This is exactly as predict-5~2 È6~1 E 6 0 È6~1 E ed by models of low-gain Class I masers. The absence of the inversion of Class II transitions 5~2 È6~1 E and means that quasi-thermal methanol emission in all objects arises in areas without a strong 6 0 È6~1 E radiation Ðeld, which is required for the inversion.

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Section: Resultsmentioning

confidence: 99%

Section: Optical Depth E †Ectsmentioning

confidence: 99%

“…Higher optical depth is not likely, according to Kalenskii et al (1997). Then, using these corrected values, we calculated the transition excitation tem-6~1 È5 0 E perature.…”

Section: Optical Depth E †Ectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Nonequilibrium Excitation of Methanol in Galactic Molecular Clouds: Multitransitional Observations at 2 Millimeters

Slysh¹,

Kalenskii²,

Вальтц³

et al. 1999

ASTROPHYS J SUPPL S

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“…For CH 3 OH, the partition function Q(T rot )=1.28T 1.5 rot was adopted from Menten et al [52], and takes into account equal populations of A and E species [53].…”

Section: Observations Data Reduction and Analysismentioning

confidence: 99%

Observations of chemical differentiation in clumpy molecular clouds

Buckle¹,

Rodgers

Wirström

et al. 2006

Faraday Discuss.

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We have extensively mapped a sample of dense molecular clouds (L1512, TMC-1C, L1262, Per 7, L1389, L1251E) in lines of HC 3 N, CH 3 OH, SO and C 18 O. We demonstrate that a high degree of chemical differentiation is present in all of the observed clouds. We analyse the molecular maps for each cloud, demonstrating a systematic chemical differentiation across the sample, which we relate to the evolutionary state of the cloud. We relate our observations to the cloud physical, kinematical and evolutionary properties, and also compare them to the predictions of simple chemical models. The implications of this work for understanding the origin of the clumpy structures and chemical differentiation observed in dense clouds are discussed.

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