منابع مشابه
Torsionally excited methanol at 44.9 GHz
Using the Haystack Observatory 37-m radio telescope we have undertaken a search for emission in the 20 −31 E rotational transition of methanol in its first torsionally excited state (vt = 1) at 44.9 GHz. We examined seven galactic sources – six strong emitters of Class II methanol maser lines and Orion KL, the only source where this line had been previously detected. We confirm (at a level of 5...
متن کاملTorsionally mediated spin-rotation hyperfine splittings at moderate to high J values in methanol.
This paper presents an explanation based on torsionally mediated proton-spin-overall-rotation interaction for the observation of doublet hyperfine splittings in some Lamb-dip sub-millimeter-wave transitions between ground-state torsion-rotation states of E symmetry in methanol. These unexpected doublet splittings, some as large as 70 kHz, were observed for rotational quantum numbers in the rang...
متن کاملA MERLIN Study of 6 GHz Excited - state OH & 6 . 7 GHz Methanol Masers in ON 1
MERLIN observations of 6.668-GHz methanol and both 6.031and 6.035-GHz hydroxyl (OH) emission from the massive star-formation region ON1 are presented. These are the first methanol observations made in full polarization using 5 antennas of MERLIN, giving high resolution and sensitivity to extended emission. Maser features are found to lie at the southern edge of the ultra-compact HII region, fol...
متن کاملSearch for class II methanol masers at 23 . 1 GHz
In the early days of methanol maser discoveries the 9 2 − 10 1 A + transition at 23.1 GHz was found to exhibit maser characteristics in the northern star-forming region W3(OH), and probable maser emission in two other sources. Attention subsequently turned to the 6.6-GHz 5 1 − 6 0 A + methanol maser transition, which has proved a valuable tracer of early high-mass star formation. We have undert...
متن کاملA search for methanol masers at 9.978 GHz and 10.058 GHz
We performed NLTE-radiative transfer calculations for interstellar A-type methanol maser lines in order to find out under which physical conditions the level populations show strong inversion. In our model we considered collisional as well as radiative pumping and accounted for line overlap as well as for torsional excitation of the methanol molecules. The radiation field was calculated using a...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2002
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20020358