J/ApJ/880/138 Observed transitions of CH3OH and CH3CHO (Holdship+, 2019)
Observations of CH3OH and CH3CHO in a sample of protostellar outflow
sources.
Holdship J., Viti S., Codella C., Rawlings J., Jimenez-Serra I., Ayalew Y.,
Curtis J., Habib A., Lawrence J., Warsame S., Horn S.
<Astrophys. J., 880, 138 (2019)>
=2019ApJ...880..138H 2019ApJ...880..138H
ADC_Keywords: Interstellar medium; Radio lines; Molecular data; Atomic physics
Keywords: astrochemistry ; ISM: jets and outflows ; ISM: molecules
Abstract:
IRAM 30m Observations toward eight protostellar outflow sources were
taken in the 96-176GHz range. Transitions of CH3OH and CH3CHO were
detected in seven of them. The integrated emissions of the transitions
of each species that fell into the observed frequency range were
measured and fit using RADEX and LTE models. Column densities and gas
properties inferred from this fitting are presented. The ratio of the
A and E-type isomers of CH3OH indicates that the methanol observed
in these outflows was formed on the grain surface. Both species
demonstrate a reduction of terminal velocity in their line profiles in
faster outflows, indicating destruction in the post-shock gas phase.
This destruction, and a near constant ratio of the CH3OH and
CH3CHO column densities, imply it is most likely that CH3CHO also
forms on the grain surface.
Description:
Observations of eight outflow sources were obtained using the IRAM-30m
telescope. The observations contain two frequency ranges, the first
from 96 to 104GHz and the second from 152 to 176GHz.
Observations, taken using the IRAM-30m telescope's EMIR receivers and
the Fourier Transform Spectrometer back end, were carried out between
2016 June 2nd and 4th in wobbler switching mode.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 76 4 Sources and relevant parameters adapted
from Gomez-Ruiz+ (2016MNRAS.462.2203G 2016MNRAS.462.2203G)
table4.dat 202 561 Observed transitions of CH3OH and CH3CHO
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See also:
J/MNRAS/421/2786 : Modelling of shock waves molecular lines (Flower+ 2012)
J/A+A/578/A63 : MHD shock code mhd_vode (Flower+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Name of the central object
16- 17 I2 h RAh Hour of right ascension (J2000)
19- 20 I2 min RAm Minute of right ascension (J2000)
22- 25 F4.1 s RAs Second of right ascension (J2000)
27 A1 --- DE- Sign of declination (J2000)
28- 29 I2 deg DEd Degree of declination (J2000)
31- 32 I2 arcmin DEm Arcminute of declination (J2000)
34- 37 F4.1 arcsec DEs Arcsecond of declination (J2000)
39- 42 F4.1 km/s Vlsr [2.6/6.5] Local Standard of Rest velocity
44- 45 I2 Lsun Lbol [4/25] Bolometric luminosity
47- 49 I3 pc Dist [235/250] Distance
51- 76 A26 arcsec Offsets Blue/Red offsets
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 11 F11.7 GHz Freq [96.27/175.1] Frequency
13- 30 A18 --- QN Resolved quantum number
32- 37 F6.3 [s-1] logAij [-9.9/-3.7] log of transition probability, Aij
39- 45 F7.3 K El [2.3/140.7] Energy level, lower
47- 53 F7.3 K Eu [6.9/148.8] Energy level, upper
55- 56 I2 --- gu [3/42] Upper state degeneracy
58- 63 F6.3 K.km/s I [-0.075/30.41] Integrated emission
65- 69 F5.3 K.km/s e_I [0.006/6.09] Uncertainty in I
71- 75 F5.1 km/s Vmin [-20/12]? Minimum, velocity range
77- 80 F4.1 km/s Vmax [3/40]? Maximum, velocity range
82- 85 F4.1 km/s Vpeak [1/17]? Emission peak velocity
87- 91 F5.3 K Tpeak [0.017/3.4]? Emission peak antenna temperature
93- 97 F5.3 K rms [0.003/0.03] RMS noise in spectrum
99-120 F22.4 cm-2 nu [-1538770577890517/1.36e+16] Upper state
column density
122-142 F21.4 cm-2 e_nu [4100957241/8989237408855261] Uncertainty in
upper state column density
144-150 F7.4 [-] ln(n/g) [14/35]? Natural log of nu/gu
152-161 F10.4 [-] e_ln(n/g) [-1880/48] Uncertainty in ln(n/g)
163-167 A5 --- Detect Is line detected, True/False?
169-173 A5 --- Blend Are lines blended, True/False?
175-180 F6.3 arcsec Beam [14/25.6] Main beamsize
182-186 F5.3 --- FF [0.38/0.67] Filling factor
188-193 A6 --- Species Species (ch3cho or ch3oh)
195-202 A8 --- Source Source identifier
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Jan-2021