J/A+A/696/A140 DCO+ and DCN 1-0 survey in cold clumps (Mo+, 2025)
DCO+ and DCN 1-0 survey toward a sample of Planck cold clumps.
Mo F., Wang J., Liu S., Duan Y., Feng H., Li Y., Lu Z., Luo R., Ou C.,
Xu Y., Yan Z.
<Astron. Astrophys. 696, A140 (2025)>
=2025A&A...696A.140M 2025A&A...696A.140M (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Radio lines
Keywords: methods: observational - ISM: abundances - ISM: clouds -
ISM: molecules - radio lines: ISM
Abstract:
Deuterated molecules can be used to study the physical conditions and
the astro-chemical evolution of molecular clouds. Large-sample surveys
for deuterated molecules are needed to understand the enhancement of
deuterated molecules from diffuse molecular gas to cold cores. A
single-pointing survey toward the 559 Planck cold clumps of the Early
Cold Core Catalogue (ECC) has been conducted using the Arizona Radio
Observatory 12-meter telescope, focusing on the J=1-0 transitions of
DCO+ and DCN. The survey included observations of 309 cores for DCO+
and DCN 1-0 simultaneously, followed by 71 of these cores where
DCO+ 1-0 was detected for H13CO+ and H13CN 1-0 simultaneously,
aiming to determine the deuterated fraction (D_frac). Additionally,
250 cores were observed for DCO+, DCN, H13CO+ and H13CN 1-0
simultaneously. Among the 309 sources, DCO+ and DCN 1-0 were detected
in 79 and 11 sources, with a detection rates of 25.6% and 3.6%
respectively. In the 250 sources observed for all four species, DCO+,
DCN, H13CO+ and H13CN 1-0 were detected in 58, 9, 57 and 13
sources, with a detection rate of 23.2%, 3.6%, 22.8% and 5.2%
respectively. The D_frac(HCO+) values in 112 sources range from 0.89%
to 7.4% with a median value of 3.1%, while Dfrac(HCN) values in 11
sources range from 1.5% to 5.5% with a median value of 2.3%. The line
widths of DCO+ and H13CO+ 1-0 detections are mostly within 1km/s.
The similarity in D_frac values between HCO+ and HCN indicates that
the higher detection rate of DCO+ 1-0 compared with DCN 1-0 is due to
the lower critical density of DCO+ 1-0. We suggest that the
enhancement of DCO+ and DCN likely begins in the early diffuse stage
of the molecular cloud, rather than during the cold core formation
stage.
Description:
With the aim to understand the enhancement of deuterated molecules
from diffuse molecular gas to cold cores, we conducted a
single-pointing survey toward 559 Planck cold clumps of ECC for DCO+
and DCN 1-0 using the ARO 12m telescope. This included observations of
309 cores for DCO+ and DCN 1- 0 simultaneously, followed by 71 of
these cores in which DCO+ 1-0 was detected for H13CO+ and H13CN
1-0 simultaneously, with the aim to determine Dfrac . Additionally,
250 cores were observed for DCO+, DCN, H13CO+, and H13CN 1-0
simultaneously. The observed parameters, including W, VLSR, and FWHM,
were presented. The detection rates and Dfrac for HCO+ and HCN were
also presented. Potential reasons for the different detection rates
and the similar Dfrac for HCO+ and HCN in Planck cold clumps were
discussed.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 55 151 Sources with detection of DCO+, DCN, H13CO+
or H13CN 1-0
tablea2.dat 40 138 Parameters of detected DCO+ 1-0
tablea3.dat 40 20 Parameters of detected DCN 1-0
tablea4.dat 40 124 Parameters of detected H13CO+ 1-0
tablea5.dat 40 33 Parameters of detected H13CO+ 1-0
tablea6.dat 103 152 Dfrac(HCO+) and Dfrac(HCN)
tableb1.dat 59 32 DCO+ 1-0 observed with the high velocity
resolution mode (AROWS mode 5)
tablee1.dat 37 228 228 sources without DCO+ or DCN 1-0 detection
with the low velocity resolution mode
(AROWS mode 3)
tablee2.dat 37 180 180 sources without DCO+, DCN, H13CO+ and
H13CN 1-0 detection with the high velocity
resolution mode (AROWS mode 13)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Source name (GLLL.ll+BB.b)
14- 15 I2 h RAh Right ascension (J2000)
16 A1 --- --- [:]
17- 18 I2 min RAm Right ascension (J2000)
19 A1 --- --- [:]
20- 24 F5.2 s RAs Right ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
29 A1 --- --- [:]
30- 31 I2 arcmin DEm Declination (J2000)
32 A1 --- --- [:]
33- 37 F5.2 arcsec DEs Declination (J2000)
39 A1 --- DCO+ DCO+ detection (1)
41 A1 --- DCN DCN detection(1)
43 A1 --- H13CO+ H13CO+ detection (1)
45 A1 --- H13CN H13CN detection (1)
47- 50 F4.2 kpc Dist ? Kinematic distance
52- 55 F4.1 K Tex Excitation temperature
--------------------------------------------------------------------------------
Note (1): Detection flag as follows:
Y = detection
/ = non-detection
- = non-observation
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Source name (GLLL.ll+BB.b)
14- 17 F4.2 K.km/s W Integrated intensity of DCO+
19- 22 F4.2 K.km/s e_W Error of integrated intensity of DCO+
24- 28 F5.1 km/s VLSR VLSR of DCO+
30- 32 F3.1 km/s e_VLSR Error of VLSR of DCO+
34- 36 F3.1 km/s FWHM FWHM of DCO+
38- 40 F3.1 km/s e_FWHM Error of FWHM of DCO+
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Source name (GLLL.ll+BB.b)
14- 17 F4.2 K.km/s W Integrated intensity of DCN
19- 22 F4.2 K.km/s e_W Error of integrated intensity of DCN
24- 28 F5.1 km/s VLSR VLSR of DCN
30- 32 F3.1 km/s e_VLSR Error of VLSR of DCN
34- 36 F3.1 km/s FWHM FWHM of DCN
38- 40 F3.1 km/s e_FWHM Error of FWHM of DCN
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Source name (GLLL.ll+BB.b)
14- 17 F4.2 K.km/s W Integrated intensity of H13CO+
19- 22 F4.2 K.km/s e_W Error of integrated intensity of H13CO+
24- 28 F5.1 km/s VLSR VLSR of H13CO+
30- 32 F3.1 km/s e_VLSR Error of VLSR of H13CO+
34- 36 F3.1 km/s FWHM FWHM of H13CO+
38- 40 F3.1 km/s e_FWHM Error of FWHM of H13CO+
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Source name (GLLL.ll+BB.b)
14- 17 F4.2 K.km/s W Integrated intensity of H13CN
19- 22 F4.2 K.km/s e_W Error of integrated intensity of H13CN
24- 28 F5.1 km/s VLSR VLSR of H13CN
30- 32 F3.1 km/s e_VLSR Error of VLSR of H13CN
34- 36 F3.1 km/s FWHM FWHM of H13CN
38- 40 F3.1 km/s e_FWHM Error of FWHM of H13CN
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Source name (GLLL.ll+BB.b)
14- 17 F4.2 K.km/s WDCO+ ? Integrated intensity of DCO+
19- 22 F4.2 K.km/s e_WDCO+ ? Error of integrated intensity of DCO+
24 A1 --- l_lWDCO+ Limit flag on lWDCO+
25- 28 F4.2 K.km/s lWDCO+ ? Upper/lower limit of W of DCO+
30- 33 F4.2 K.km/s WDCN ? Integrated intensity of DCN
35- 38 F4.2 K.km/s e_WDCN ? Error of W of DCN
40 A1 --- l_lWDCN Limit flag on WDCN
41- 44 F4.2 K.km/s lWDCN ? Upper/lower limit of W of DCN
46- 49 F4.2 K.km/s WH13CO+ ? Integrated intensity of H13CO+
51- 54 F4.2 K.km/s e_WH13CO+ ? Error of W of H13CO+
56 A1 --- l_WH13CO+ Limit flag on lWH13CO+
57- 60 F4.2 K.km/s lWH13CO+ ? Upper/lower limit of W of H13CO+
62- 65 F4.2 K.km/s WH13CN ? Integrated intensity of H13CN
67- 70 F4.2 K.km/s e_WH13CN ? Error of W of H13CN
72 A1 --- l_lWH13CN Limit flag on lWH13CN
73- 76 F4.2 K.km/s lWH13CN ? Upper/lower limit of W of H13CN
78- 80 F3.1 % DfHCO+ ? Deuterated fraction of HCO+
82- 84 F3.1 % e_DfHCO+ ? Error of deuterated fraction of HCO+
86 A1 ---- l_DfHCO+ Limit flag on lDfHCO+
87- 90 F4.1 % lDfHCO+ ? Upper/lower limit of deuterated fraction
of HCO+
92- 94 F3.1 % DfHCN ? Deuterated fraction of HCN
96- 98 F3.1 % e_DfHCN ? Error of deuterated fraction of HCN
100 A1 --- l_lDfHCN Limit flag on lDfHCN
101-103 F3.1 % lDfHCN ? Upper/lower limit of deuterated fraction
of HCN
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Source name
14- 17 F4.2 K.km/s Wh Integrated intensity of DCO+ with
high resolution
19- 22 F4.2 K.km/s e_Wh Error of integrated intensity of DCO+ with
high resolution
24- 27 F4.1 km/s VLSRh VLSR of DCO+ with high resolution
29- 31 F3.1 km/s e_VLSRh Error of VLSR of DCO+ with high resolution
33- 35 F3.1 km/s FWHMh FWHM of DCO+ with high resolution
37- 39 F3.1 km/s e_FWHMh Error of FWHM of DCO+ with high resolution
41- 44 F4.2 K.km/s Wl Integrated intensity of DCO+ with
low resolution
46- 49 F4.2 K.km/s e_Wl Error of integrated intensity of DCO+ with
low resolution
51- 54 F4.2 --- h/l Integrated intensity ratio of DCO+ with
high/low resolution
56- 59 F4.2 --- e_h/l Error of integrated intensity ratio with
high/low resolution
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablee1.dat tablee2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Source name
14- 15 I2 h RAh Right ascension (J2000)
16 A1 --- --- [:]
17- 18 I2 min RAm Right ascension (J2000)
19 A1 --- --- [:]
20- 24 F5.2 s RAs Right ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
29 A1 --- --- [:]
30- 31 I2 arcmin DEm Declination (J2000)
32 A1 --- --- [:]
33- 37 F5.2 arcsec DEs Declination (J2000)
--------------------------------------------------------------------------------
History:
From Mo Fu, mofu(at)st.gxu.edu.cn
Acknowledgements:
This work is supported by National Key R&D Program of China under
grant 2023YFA1608204 and the National Natural Science Foundation of
China grant 12173067.
(End) Patricia Vannier [CDS] 17-Mar-2025