J/A+A/649/A21 ATLASGAL deuteration of ammonia (Wienen+, 2021)
ATLASGAL-selected massive clumps in the inner Galaxy.
IX. Deuteration of ammonia.
Wienen M., Wyrowski F., Walmsley C.M., Csengeri T., Pillai T.,
Giannetti A., Menten K.M.
<Astron. Astrophys. 649, A21 (2021)>
=2021A&A...649A..21W 2021A&A...649A..21W (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium; Millimetric/submm sources ; Radio lines
Keywords: surveys - submillimeter - radio lines: ISM - ISM: molecules -
stars: massive - stars: formation
Abstract:
Deuteration has been used as a tracer of the evolutionary phases of
low- and high-mass star formation. The APEX Telescope Large Area
Survey (ATLASGAL) provides an important repository for a detailed
statistical study of massive star-forming clumps in the inner Galactic
disc at different evolutionary phases.
We study the amount of deuteration using NH2D in a representative
sample of high-mass clumps discovered by the ATLASGAL survey covering
various evolutionary phases of massive star formation. The deuterium
fraction of NH3 is derived from the NH2D 111-101ortho
transition at ∼86GHz and NH2D 111-101para line at ∼110GHz.
This is refined for the first time by measuring the NH2D excitation
temperature directly with the NH2D 212-202para transition at
∼74GHz. Any variation of NH3 deuteration and ortho-to-para ratio with
the evolutionary sequence is analysed.
Unbiased spectral line surveys at 3mm were conducted towards ATLASGAL
clumps between 85 and 93GHz with the Mopra telescope and from 84 to
115GHz using the IRAM 30m telescope. A subsample was followed up in
the NH2D transition at 74GHz with the IRAM 30m telescope. We
determined the deuterium fractionation from the column density ratio
of NH2D and NH3 and measured the NH2D excitation temperature for
the first time from the simultaneous modelling of the 74 and 110GHz
line using MCWeeds. We searched for trends in NH3 deuteration with
the evolutionary sequence of massive star formation. We derived the
column density ratio from the 86 and 110GHz transitions as an
estimate of the NH2D ortho-to-para ratio.
We find a large range of the NH2D to NH3 column density ratio up
to 1.6±0.7 indicating a high degree of NH3 deuteration in a
subsample of the clumps. Our analysis yields a clear difference
between NH3 and NH2D rotational temperatures for a fraction. We
therefore advocate observation of the NH2D transitions at 74 and
110GHz simultaneously to determine the NH2D temperature directly. We
determine a median ortho-to-para column density ratio of 3.7±1.2.
The high detection rate of NH2D confirms a high deuteration
previously found in massive star-forming clumps. Using the excitation
temperature of NH2D instead of NH3 is needed to avoid an
overestimation of deuteration. We measure a higher detection rate of
NH2D in sources at early evolutionary stages. The deuterium
fractionation shows no correlation with evolutionary tracers such as
the NH3 (1,1) line width, or rotational temperature.
Description:
The NH2D transitions at 86GHz and 110GHz of subsamples from the
ATLASGAL survey, which reaches a Galactic longitude of ±60deg and
latitude of ±1.5deg, were observed within two unbiased spectral-line
follow-ups. We used the Mopra 22m telescope to measure the NH2D
111-101 ortho transition at ∼86GHz of a flux-limited sample in the
fourth quadrant. Ortho NH2D as well as the NH2D 111-101 para
line at ∼110GHz were observed in the first quadrant using the IRAM 30m
telescope. In addition, we measured the NH2D 212-202 para
transition at ∼74GHz toward a subsample of the 24 brightest clumps in
deuterated ammonia. The NH2D spectra at 74, 86, 110GHz are shown and
line parameters are derived for 390 ATLASGAL sources. The optical
depth, LSR velocity, linewidth, main beam brightness temperature and
column density of each clump were determined. We measured the NH2D
excitation temperature from the simultaneous modelling of the 74 and
110 GHz transitions using MCWeeds and show the comparison to the NH3
rotational temperature derived for ATLASGAL sources by Wienen et al.
(2012A&A...544A.146W 2012A&A...544A.146W, Cat. J/A+A/544/A146). Furthermore, the deuterium
fractionation is calculated from the NH2D to NH3 column density
ratio as well as the ortho-to-para column density ratio. We show
correlation plots of the NH3 deuteration and the ortho-to-para ratio
with evolutionary tracers.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 93 264 Source positions, properties of NH2D at 86GHz
and NH3 rotational temperature
table3.dat 64 108 Line parameters of NH2D at 110GHz
table4.dat 84 23 Properties of NH2D line at 74GHz
table5.dat 66 264 Column densities and deuteration of
NH3 and NH2D at 86GHz
table6.dat 36 53 Column density of NH2D at 110GHz and
ortho-to-para ratio
table9.dat 38 57 Velocity integrated intensity of NH2D at 86GHz
and 110GHz and the ratio of both integrated
intensities
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See also:
J/A+A/570/A65 : ATLASGAL massive clumps CO depletion (Giannetti+, 2014)
J/A+A/586/A149 : SiO in ATLASGAL-selected massive clumps (Csengeri+, 2016)
J/A+A/599/A139 : ATLASGAL massive clumps dust characterization (Koenig+, 2017)
J/A+A/602/A37 : Millimeter RRL in ATLASGAL-selected massive clumps (Kim+ 2017)
J/A+A/603/A33 : Temperature evolution in massive clumps (Giannetti+, 2017)
J/A+A/611/A6 : ATLASGAL massive clumps H2CO data (Tang+, 2018)
J/A+A/622/A135 : Mid-J CO emission of Top100 clumps (Navarete+, 2019)
J/A+A/644/A160 : ATLASGAL-selected massive clumps. Chemistry of PDR (Kim+ 2020)
J/A+A/544/A146 : ATLASGAL cold high-mass clumps with NH3 (Wienen+, 2012)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Source Name (GLLL.ll+B.bb)
14- 15 I2 h RAh Right Ascension (J2000)
17- 18 I2 min RAm Right Ascension (J2000)
20- 24 F5.2 s RAs Right Ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 36 F4.1 arcsec DEs Declination (J2000)
38- 41 F4.2 --- tauNH3 Optical depth of the NH3 (1,1) line
43- 47 F5.2 --- e_tauNH3 Error of the optical depth
48 A1 --- n_tauNH3 [*] Note on tauNH3 (1)
50- 56 F7.2 km/s vLSR Velocity of NH2D line at 86GHz
58- 61 F4.2 km/s e_vLSR Error of the velocity
63- 66 F4.2 km/s Deltav Linewidth
68- 71 F4.2 km/s e_Deltav Error of the linewidth
73- 76 F4.2 K TMB Main beam brightness temperature
78- 81 F4.2 K e_TMB Error of main beam brightness temperature
83- 87 F5.2 K Trot ?=99.99 rotational temperature between the
NH3 (1,1) and (2,2) inversion transition
89- 93 F5.2 K e_Trot ?=99.99 Error of rotational temperature
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Note (1): * for Sources without detected hyperfine structure or no reliable
derivation of the optical depth due to low S/N (see Sect. 3.3).
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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- 12 A12 --- Name Source Name (GLLL.ll+B.bb)
13 A1 --- m_Name [AB] Multiplicity index on Name
15- 16 I2 h RAh Right Ascension (J2000)
18- 19 I2 min RAm Right Ascension (J2000)
21- 25 F5.2 s RAs Right Ascension (J2000)
27 A1 --- DE- Declination sign (J2000)
28- 29 I2 deg DEd Declination (J2000)
31- 32 I2 arcmin DEm Declination (J2000)
34- 37 F4.1 arcsec DEs Declination (J2000)
39- 44 F6.2 km/s vLSR Velocity of NH2D line at 110GHz
46- 49 F4.2 km/s e_vLSR Error of the velocity
51- 54 F4.2 km/s Deltav110 Linewidth
56- 59 F4.2 K TMB110 Main beam brightness temperature
61- 64 F4.2 K e_TMB110 Error of main beam brightness temperature
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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- 12 A12 --- Name Source Name (GLLL.ll+B.bb)
14- 15 I2 h RAh Right Ascension (J2000)
17- 18 I2 min RAm Right Ascension (J2000)
20- 24 F5.2 s RAs Right Ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 36 F4.1 arcsec DEs Declination (J2000)
38- 43 F6.2 km/s vLSR74 Velocity of NH2D line at 74GHz
45- 48 F4.2 km/s E_vLSR74 ?=- Error of the velocity (upper value)
51- 54 F4.2 km/s e_vLSR74 ?=- Error of the velocity (lower value)
56- 58 F3.1 km/s DeltavLSR74 ?=- Linewidth
60- 62 F3.1 km/s E_DeltavLSR74 ?=- Error of the linewidth (upper value)
65- 67 F3.1 km/s e_DeltavLSR74 ?=- Error of the linewidth (lower value)
69- 73 F5.2 km/s TrotNH2D Rotational temperature between the
NH2D 111-101 line and 212-202
transition
75- 78 F4.1 km/s E_TrotNH2D ?=- Error of the rotational temperature
(upper value)
81- 84 F4.1 km/s e_TrotNH2D ?=- Error of the rotational temperature
(lower value)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Source Name (GLLL.ll+B.bb)
14- 18 F5.2 10+15cm-2 NNH3 ?=- NH3 column density
20- 23 F4.2 10+15cm-2 e_NNH3 ?=- Error of NH3 column density
25- 28 F4.2 --- eta ?=- Beam filling factor
30- 33 F4.2 --- e_eta ?=- Error of the beam filling factor
35- 40 F6.2 10+13cm-2 NNH2D(86) ?=- Column density of NH2D at 86GHz
42- 47 F6.2 10+13cm-2 e_NNH2D(86) ?=- Error of the NH2D column density
49- 52 F4.2 --- [NH2D/NH3] ?=- Deuteration
54- 58 F5.2 --- e_[NH2D/NH3] ?=- Error of deuteration
60- 62 F3.1 K.km/s TMBdv(86) Velocity integrated intensity of
NH2D at 86GHz
64- 66 F3.1 K.km/s e_TMBdv(86) Error of velocity integrated intensity
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Source Name (GLLL.ll+B.bb)
14- 18 F5.2 10+13cm-2 NNH2D(110) Column density of NH2D at 110GHz
20- 24 F5.2 10+13cm-2 e_NNH2D(110) Error of the NH2D column density
26- 30 F5.2 --- No(86)/Np(110) Column density ratio of ortho to para
NH2D, Northo(86GHz)/Npara(110GHz)
32- 36 F5.2 --- e_No(86)/Np(110) Error of column density ratio
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Source Name
14- 16 F3.1 K.km/s TMBdv(86) Velocity integrated intensity of
NH2D at 86GHz
18- 20 F3.1 K.km/s e_TMBdv(86) Error of velocity integrated
intensity of ortho NH2D
22- 24 F3.1 K.km/s TMBdv(110) Velocity integrated intensity of
NH2D at 110GHz
26- 28 F3.1 K.km/s e_TMBdv(110) Error of velocity integrated
intensity of para NH2D
30- 33 F4.1 --- TMBdv(86)/TMBdv(110) Ratio of ortho to para NH2D
velocity integrated intensity
35- 38 F4.1 --- e_TMBdv(86)/TMBdv(110) Error of velocity integrated
intensity ratio
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Acknowledgements:
Marion Wienen, mwienen(at)mpifr-bonn.mpg.de
References:
Giannetti et al., Paper I 2014A&A...570A..65G 2014A&A...570A..65G, Cat. J/A+A/570/A65
Csengeri et al., Paper II 2016A&A...586A.149C 2016A&A...586A.149C, Cat. J/A+A/586/A149
Konig et al., Paper III 2017A&A...599A.139K 2017A&A...599A.139K, Cat. J/A+A/599/A139
Kim et al., Paper IV 2017A&A...602A..37K 2017A&A...602A..37K, Cat. J/A+A/502/A37
Giannetti et al., Paper V 2017A&A...603A..33G 2017A&A...603A..33G, Cat. J/A+A/603/A33
Tang et al., Paper VI 2018A&A...611A...6T 2018A&A...611A...6T, Cat. J/A+A/611/A6
Navarete et al., Paper VII 2019A&A...622A.135N 2019A&A...622A.135N, Cat. J/A+A/622/A135
Kim et al., Paper VIII 2020A&A...644A.160K 2020A&A...644A.160K, Cat. J/A+A/644/A160
Schuller et al., 2009A&A...504..415S 2009A&A...504..415S,
ATLASGAL - the APEX telescope large area survey of the galaxy at 870µm.
(End) Marion Wienen [MPIfR, Bonn], Patricia Vannier [CDS] 22-Apr-2021