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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 (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:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 143 84 List of spectra sp/* 0 84 Individual fits spectra
Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
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
Acknowledgements: Shaoshan Zeng, z.shaoshan(at)qmul.ac.uk
(End) Shaoshan Zeng [QMUL, London], Patricia Vannier [CDS] 02-Jun-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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