J/A+A/603/A22 IRDCs cores spectra of HCN and HNC isotopologue (Zeng+, 2017)
15N fractionation in infrared-dark cloud cores.
Zeng S., Jimenez-Serra I., Cosentino G., Viti S., Barnes A.T.,
Henshaw J.D., Caselli P., Fontani F., Hily-Blant P.
<Astron. Astrophys. 603, A22 (2017)>
=2017A&A...603A..22Z 2017A&A...603A..22Z (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Molecular clouds ; Line Profiles
Keywords: ISM: molecules - astrochemistry - star: formation
Abstract:
We present the results of the measurement of nitrogen fractionation in
a sample of infrared-dark clouds (IRDCs) cores which are believed to
be the precursors of high-mass stars and star clusters. We observed
the J=1-0 transitions of HCN, H13/CN, HC15/N, HN13/C, and
H15/NC towards a sample of 22 cores in four IRDCs using the IRAM 30m
telescope.Assuming LTE and a temperature of 15K, the 14N/15/N ratios
measured are consistent with the terrestrial atmosphere(TA) and
protosolar nebula(PSN) values, and with the ratios measured in
low-mass prestellar cores. However, the 14N/15/N ratios measured in
cores C1, C3, F1, F2, and G2 do not agree with the results from
similar studies towards the same cores using nitrogen bearing
molecules with nitrile functional group(-CN) and nitrogen hydrides
(-NH) although the ratio spread covers a similar range. Relatively low
14N/15/N ratios amongst the four-IRDCs were measured in IRDC G which
are comparable to those measured in small cosmomaterials and
protoplanetary disks. The low average gas density of this cloud
suggests that the gas density, rather than the gas temperature, may be
the dominant parameter influencing the initial nitrogen isotopic
composition in young PSN.
Description:
Reduced FITS spectra of H13/CN, HC15/N, HN13/C, and H15/NC
toward 22 cores in 4 IRDCs: G028.37+00.07, G034.43+00.24,
G034.77-00.55, and G035.39-00.33 (Clouds C, F, G, and H respectively).
The spectra were obtained with the IRAM 30 m telescope. The EMIR
receivers were tuned at 87GHz and the FTS spectrometer provided a
spectral resolution of 200kHz.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 143 84 List of spectra
sp/* . 84 Individual fits spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 24 I5 --- Nx Number of points
26- 48 A23 --- Obs.Date Observation date (YYYY-MM-DDThh:mm:ss.sss)
50- 61 E12.6 Hz bFreq Lower value of frequency interval
63- 73 E11.6 Hz BFreq Upper value of frequency interval
75- 80 I6 Hz dFreq Frequency resolution
82- 83 I2 Kibyte size Size of FITS file
85-104 A20 --- FileName Name of FITS file, in subdirectory sp
106-143 A38 --- Title Title of the FITS file
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Acknowledgements:
Shaoshan Zeng, z.shaoshan(at)qmul.ac.uk
(End) Shaoshan Zeng [QMUL, London], Patricia Vannier [CDS] 02-Jun-2017