J/A+A/428/1019 Rest frequencies of methanol maser lines (Mueller+, 2004)
Accurate rest frequencies of methanol maser and dark cloud lines.
Mueller H.S.P., Menten K.M., Maeder H.
<Astron. Astrophys., 428, 1019-1026 (2004)>
=2004A&A...428.1019M 2004A&A...428.1019M
ADC_Keywords: Atomic physics ; Masers ; Molecular clouds ; Radio lines
Keywords: masers - molecular data - ISM: molecules - radio lines: ISM -
line: identification - line: profiles
Abstract:
We report accurate laboratory measurements of selected methanol
transition frequencies between 0.834 and 230GHz in order to facilitate
astronomical velocity analyses. New data have been obtained between 10
and 27GHz and between 60 and 119GHz. Emphasis has been put on known or
potential interstellar maser lines as well as on transitions suitable
for the investigation of cold dark clouds. Because of the narrow line
widths (<0.5km/s) of maser lines and lines detected in dark molecular
clouds, accurate frequencies are needed for comparison of the
velocities of different methanol lines with each other as well as
with lines from other species. In particular, frequencies for a
comprehensive set of transitions are given which, because of their
low energy levels (<20cm-1 or 30K), are potentially detectable in
cold clouds. Global Hamiltonian fits generally do not yet yield the
required accuracy. Additionally, we report transition frequencies for
other lines that may be used to test and to improve existing
Hamiltonian models.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 74 47 Methanol maser transitions
table2.dat 75 39 Accurately known methanol transitions detected
or potentially detectable in dark clouds
refs.dat 169 40 References
table3.dat 41 73 Other methanol transitions measured in the
course of the present investigation
tables.tex 131 225 LaTeX version of the tables
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See also:
J/A+A/413/233 : 12.2 GHz methanol survey (Blaszkiewicz+, 2004)
J/A+A/432/737 : General Catalogue of 6.7GHz Methanol Masers (Pestalozzi+ 2005)
J/A+AS/134/115 : Medicina 6.7GHz methanol masers survey (Slysh+ 1999)
J/A+AS/143/269 : 6.7GHz methanol maser emission survey (Szymczak+, 2000)
J/AZh/72/22 : A 95 GHz Survey of Methanol Masers (Valtts+, 1995)
Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Class Maser type (1)
4 A1 --- Note [g] g: lines discussed in Sect. 4.3 of the paper
6- 20 A15 --- Trans Transition, Jk (2)
21 A1 --- n_Trans [*] Note on Trans (7)
23- 34 F12.5 MHz Freq Frequency
37- 42 F6.5 MHz e_Freq Measurement uncertainty
43 A1 --- n_Freq [h] Note on Freq (3)
45- 51 F7.3 cm-1 Elow Lower state energy (4)
53- 59 F7.4 --- Smu2 Line strength, Sµ2 (D2)
61- 66 A6 --- Ref(1) Laboratory reference
68- 73 A6 --- Ref(2) Astronomical (table1) or dark cloud (table2)
reference (5)
74- 75 A2 --- n_Ref(2) [* ND NO I] Note on Ref(2) (6)
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Note (1): Gives the maser type. Interstellar methanol masers are either
class I or to II; see text and Menten (1991ApJ...380L..75M 1991ApJ...380L..75M, and 1991,
in Skylines, Proc. Third Haystack Observatory Meeting, ed. A.D.
Haschick, & P.T.P. Ho (San Francisco: ASP), 119)
Note (2): The parity of A symmetry transitions is given as superscript.
If the parities of the upper (left) and lower (right) state differ,
the parities are given as upper and lower superscript, respectively.
Note (3): The 1H hyperfine splitting has been resolved to some extent
in the laboratory.
-- For the J=1-1 transition, four components, spread over 19.4km/s,
have been observed. The frequency in the table is the one of the
strongest component; the intensity weighted average is 1kHz lower.
-- For the J=3-3 transition, two components, split by 0.19km/s,
have been observed.
Note (4): Lower state level energies are all relative to the
ground-state (0+0) level of the A-symmetry species. The E-type
ground state (1-1) level is at a 5.490cm-1 higher energy
Note (5): For table1.dat: only the first reference reporting maser
emission in this line is given.
For table2.dat: only references reporting the first detection of a
line in cold (T≃10K) dark clouds are listed. For non-dark cloud
astronomical references to first detections, see Lovas (2004, J. Phys.
Chem Ref. Data, 33, 177)
Note (6): Note on references are as follows:
*: this line was earlier detected in thermal emission or absorption.
See Lovas (2004, J. Phys. Chem Ref. Data, 33, 177) for relevant
references.
I: References that report observations of a given line that did not
yield its detection.
ND: no astronomical detection is reported in the latter reference
NO: the line is not observable from the ground
Note (7): Note on Trans:
*: This line appears in enhanced absorption (i.e. is over-cooled)
against the cosmological microwave background radiation.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Ref Reference code
9- 27 A19 --- BibCode BibCode
29- 52 A24 --- Aut Author's name
53-169 A117 --- Com Comments
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1 I1 --- Vt [0/1] Torsional state
3- 18 A16 --- Trans Transition
20- 29 F10.3 MHz Freq Frequency
31- 34 F4.3 MHz e_Freq rms uncertainty on Freq
35 A1 --- n_Freq [xT] Note on Freq (1)
38- 39 A2 --- Note [ND NO U] Note (2)
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Note (1): Tsunekawa et al. (1995, Department of Physics, Toyama Univerity,
Japan) give 111626.846(.030)MHz for the frequency of the line marked
with T; we suspect a typographical error, see Sect. 4.1, where also
some assignments for J>30 are discussed. Heuvel & Dymanus (1973, J.
Mol. Spectrosc., 45, 282) give 17513.34127(.00020)MHz for the unsplit
position of the line marked with x.
Note (2): All lines, except those marked "ND" have been detected in
astronomical sources. See Lovas (2004, J. Phys. Chem Ref. Data, 33,
177) for references to first detections.
-- ND means that no astronomical detection is reported in the
latter reference.
-- NO means that the line is not observable from the ground
-- U means that this line is listed as unidentified in Lovas
(2004, J. Phys. Chem Ref. Data, 33, 177).
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Mar-2005