J/A+A/609/A129ivo://CDS.VizieR/J/A+A/609/A129doi:10.26093/cds/vizier.36090129CDSColzi L.Fontani F.Caselli P.Ceccarelli C.Hily-Blant P.,Bizzocchi L.2018-02-08T08:32:54Z2018-02-01T07:57:27ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frinterstellar-mediumradio-astronomyThe ratio between the two stable isotopes of nitrogen, ^14^N and ^15^N, is well measured in the terrestrial atmosphere (~272), and for the pre-solar nebula (~441, deduced from the solar wind). Interestingly, some pristine solar system materials show enrichments in 15N with respect to the pre-solar nebula value. However, it is not yet clear if and how these enrichments are linked to the past chemical history because we have only a limited number of measurements in dense star-forming regions. In this respect, dense cores, which are believed to be the precursors of clusters and also contain intermediate- and high-mass stars, are important targets because the solar system was probably born within a rich stellar cluster, and such clusters are formed in high-mass star-forming regions. The number of observations in such high-mass dense cores has remained limited so far. In this work, we show the results of IRAM-30m observations of the J=1-0 rotational transition of the molecules HCN and HNC and their 15N-bearing counterparts towards 27 intermediate- and high-mass dense cores that are divided almost equally into three evolutionary categories: high-mass starless cores, high-mass protostellar objects, and ultra-compact Hii regions. We have also observed the DNC(2-1) rotational transition in order to search for a relation between the isotopic ratios D/H and ^14^N/^15^N. We derive average ^14^N/^15^N ratios of 359+/-16 in HCN and of 438+/-21 in HNC, with a dispersion of about 150-200. We find no trend of the ^14^ N/^15^ N ratio with evolutionary stage. This result agrees with what has been found for N_2_H^+^ and its isotopologues in the same sources, although the ^14^N/^15^N ratios from N2H+ show a higher dispersion than in HCN/HNC, and on average, their uncertainties are larger as well. Moreover, we have found no correlation between D/H and ^14^N/^15^N in HNC. These findings indicate that (1) the chemical evolution does not seem to play a role in the fractionation of nitrogen, and that (2) the fractionation of hydrogen and nitrogen in these objects is not related.2018A&A...609A.129Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/609/A129CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/609/A129https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/609/A129http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/609/A129https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/609/A129https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/609/A129http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/609/A129GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/609/A129/sources (*Total column densities (beam-averaged), of H^15^NC, HN^13^C, DNC (table 3) and HC^15^N and H^13^CN(1-0) transitions (table 4))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/609/A129/sources?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/609/A129/sources?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/609/A129/sources?GETtext/xml+votable180.050000true3.609583364.47416670.0055555555555555566/3068 14299 14307 14317 14353 14594 14622 14689 15430 15629 24507 24554 28912 29103 30256 30318-30319 30425 30595https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/609/A129?format=asciiRadiodefaultJ/A+A/609/A129/sources*Total column densities (beam-averaged), of H^15^NC, HN^13^C, DNC (table 3) and HC^15^N and H^13^CN(1-0) transitions (table 4)SimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTypeType (HMPO, HMSC or UCHII)src.classcharSourceSource namemeta.id;meta.maincharn_Source[w] Note on Source (1)meta.notecharl_N(H15NC)[<= ] Limit flag on N(H15NC)meta.code.errorcharN(H15NC)Total H^15^NC column density (beam-averaged)1e+10cm**-2phys.columnDensityinte_N(H15NC)? rms uncertainty on N(H15NC) (2)1e+10cm**-2stat.errorintnullablen_N(H15NC)[ut] Note on N(H15NC) (1)meta.notecharDN1? Error on N(H15NC) without considering the calibration error1e+10cm**-2stat.errorintnullableN(HN13C)Total HN^13^C column density (beam-averaged)1e+11cm**-2phys.columnDensityfloate_N(HN13C)rms uncertainty on N(HN13C) (2)1e+11cm**-2stat.errorfloatDN2Error on N(HN13C) without considering the calibration error1e+11cm**-2stat.errorfloatN(DNC)Total DNC column density (beam-averaged)1e+11cm**-2phys.columnDensityfloate_N(DNC)rms uncertainty on N(DNC) (2)1e+11cm**-2stat.errorfloatl_HNC/H15NC[>= ] Limit flag on HNC/H15NCmeta.code.errorcharHNC/H15NCHNC/H^15^NC isotopic ratio (3)spect.line.intensity;arith.ratiointe_HNC/H15NC? rms uncertainty on HNC/H15NC (2)stat.errorintnullableHNC/DNCHNC/DNC isotopic ratio (4)spect.line.intensity;arith.ratiointe_HNC/DNCrms uncertainty on HNC/DNC (2)stat.errorintDNC/HNCDNC/HNC isotopic ratiospect.line.intensity;arith.ratiodoublee_DNC/HNCrms uncertainty on DNC/HNC (2)stat.errordoublel_N(HC15N)[<= ] Limit flag on N(HC15N)meta.code.errorcharN(HC15N)Total N(HC15N) column density (beam-averaged)1e+10cm**-2phys.columnDensityinte_N(HC15N)? rms uncertainty on N(HC15N)1e+10cm**-2stat.errorintnullablen_N(HC15N)[ut] Note on N(HC15N) (1)meta.notecharDN3? Error on N(HC15N) without considering the calibration error1e+10cm**-2stat.errorintnullableN(H13CN)Total H^13^CN column density (beam-averaged)1e+11cm**-2phys.columnDensityinte_N(H13CN)rms uncertainty on N(H13CN) (2)1e+11cm**-2stat.errorintDN4Error on N(H13CN) without considering the calibration error1e+11cm**-2stat.errorfloatl_HCN/HC15N[>= ] Limit flag on HCN/HC15Nmeta.code.errorcharHCN/HC15NHCN/HC15N isotopic ratio (3)spect.line.intensity;arith.ratiointe_HCN/HC15N? rms uncertainty on HCN/HC15N (2)stat.errorintnullableTkKinetic temperature of the clump (5)Kphys.temperatureintn_Tk[*] Note on Tk (6)meta.notechardncShow the DNC spectrummeta.ref.urlcharh13cnShow the H^13^CN spectrummeta.ref.urlcharh15ncShow the H^15^CN spectrummeta.ref.urlcharhc15nShow the HC^15^N spectrummeta.ref.urlcharhn13cShow the HN^13^C spectrummeta.ref.urlcharFNameName used in the spectra files (7)meta.idchar_RAPositions from Simbad (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simbad (declination part)degpos.eq.dec;meta.main