J/MNRAS/409/29 Methanol line formation in outflow sources (Flower+, 2010)
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Methanol line formation in outflow sources.
Flower D.R., Pineau des Forets G., Rabli D.
=2010MNRAS.409...29F
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ADC_Keywords: Atomic physics ; Interstellar medium
Keywords: molecular data - shock waves - stars: formation - stars: low-mass -
ISM: jets and outflows - ISM: molecules
Abstract:
We report the first calculations of the spectrum of methanol, arising
in shock waves in molecular outflows. The small grid of shock wave
models that we have computed incorporates the results of very recent
computations of the rate coefficients for the collisional excitation
of methanol by ortho- and para-H2 and by He. The two strongest
transitions, one of A- and the other of E-type methanol, are masers
that have been observed in a Class I methanol maser source, which is
believed to be related to a molecular outflow. The same collisional
propensities that give rise to population inversion and maser action
can, in other transitions, lead to population anti-inversion and the
lines appearing in absorption against the cosmic background radiation.
We attempted to model specifically the outflow source L1157 B1, in
which transitions of methanol have been observed recently by means of
the Herschel satellite. Comparison with the predictions of the shock
wave models is complicated by uncertainty in the value of the beam
filling factor that should be adopted.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 84 462 *CH3OH A-type (I=3/2), n_H_=2x10^4^cm-3
tablea2.dat 84 636 *CH3OH A-type (I=3/2), n_H_=2x10^5^cm-3
tablea3.dat 84 436 *CH3OH E-type (I=1/2), n_H_=2x10^4^cm-3
tablea4.dat 84 603 *CH3OH E-type (I=1/2), n_H_=2x10^5^cm-3
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Note on table*.dat: the A-type has the nuclear spins of the 3 protons
parallel (i.e. the nuclear quantum number I=3/2), which in the E-type
the nuclear quantum number is I=1/2.
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See also:
J/MNRAS/406/1745 : H2O in interstellar shock waves (Flower+, 2010)
Byte-by-byte Description of file: tablea1.dat tablea3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Jup Upper level J number (G1)
4- 6 I3 --- Kup Upper level K number (G1)
8- 10 I3 --- Jlow Lower level J number (G1)
12- 14 I3 --- Klow Lower level K number (G1)
16- 24 F9.4 K Eup Excitation energy of the upper level of the
transition, relative to the 0 0 0 ground level
25- 34 F10.5 GHz nu Frequency of transition
36- 44 E9.3 K.km/s v10n2e4 Line intensity, TdV, for shock speed
vs=10km/s and n_H_=2x10^4^cm^-3^ (G2)
46- 54 E9.3 K.km/s v15n2e4 Line intensity, TdV, for shock speed
vs=15km/s and n_H_=2x10^4^cm^-3^ (G2)
56- 64 E9.3 K.km/s v20n2e4 Line intensity, TdV, for shock speed
vs=20km/s and n_H_=2x10^4^cm^-3^ (G2)
66- 74 E9.3 K.km/s v30n2e4 Line intensity, TdV, for shock speed
vs=30km/s and n_H_=2x10^4^cm^-3^ (G2)
76- 84 E9.3 K.km/s v40n2e4 Line intensity, TdV, for shock speed
vs=40km/s and n_H_=2x10^4^cm^-3^ (G2)
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Byte-by-byte Description of file: tablea2.dat tablea4.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Jup Upper level J number (G1)
4- 6 I3 --- Kup Upper level K number (G1)
8- 10 I3 --- Jlow Lower level J number (G1)
12- 14 I3 --- Klow Lower level K number (G1)
16- 24 F9.4 K Eup Excitation energy of the upper level of the
transition, relative to the 0 0 0 ground level
26- 34 F9.4 GHz nu Frequency of transition
36- 44 E9.3 K.km/s v10n2e5 Line intensity, TdV, for shock speed
vs=10km/s and n_H_=2x10^5^cm^-3^ (G2)
46- 54 E9.3 K.km/s v15n2e5 Line intensity, TdV, for shock speed
vs=15km/s and n_H_=2x10^5^cm^-3^ (G2)
56- 64 E9.3 K.km/s v20n2e5 Line intensity, TdV, for shock speed
vs=20km/s and n_H_=2x10^5^cm^-3^ (G2)
66- 74 E9.3 K.km/s v30n2e5 Line intensity, TdV, for shock speed
vs=30km/s and n_H_=2x10^5^cm^-3^ (G2)
76- 84 E9.3 K.km/s v40n2e5 Line intensity, TdV, for shock speed
vs=40km/s and n_H_=2x10^5^cm^-3^ (G2)
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Global notes:
Note (G1): J is the rotational quantum number and K is its projection on
the symmetry axis of the molecule
Note (G2): Where vs is the shock speed and n_H_ the pre-shock density.
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History:
From electronic version of the journal
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(End) Patricia Vannier [CDS] 11-Apr-2011