J/ApJ/899/145ivo://CDS.VizieR/J/ApJ/899/145doi:10.26093/cds/vizier.18990145CDSYu H.Z.Zhang J.S.Henkel C.Yan Y.T.Liu W.Tang X.D.Langer N.,Luan T.C.Chen J.L.Wang Y.X.Deng G.G.Zou Y.P.2022-03-14T07:08:41Z2021-11-08T06:12:44ZCDS support team

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

cds-question@unistra.frinterstellar-mediumstar-forming-regionschemical-abundancesmolecular-physicsmillimeter-astronomyphotometrysubmillimeter-astronomyWe present observations of 12C32S, 12C34S, 13C32S, and 12C33S J=2-1 lines toward a large sample of massive star-forming regions by using the Arizona Radio Observatory 12m telescope and the IRAM 30m. Taking new measurements of the carbon 12C/13C ratio, the 32S/34S isotope ratio was determined from the integrated 13C32S/12C34S line intensity ratios for our sample. Our analysis shows a 32S/34S gradient from the inner Galaxy out to a galactocentric distance of 12kpc. An unweighted least-squares fit to our data yields 32S/34S=(1.56{+/-}0.17)DGC+(6.75{+/-}1.22) with a correlation coefficient of 0.77. Errors represent 1{sigma} standard deviations. Testing this result by (a) excluding the Galactic center region, (b) excluding all sources with C34S opacities >0.25, (c) combining our data and old data from previous study, and (d) using different sets of carbon isotope ratios leads to the conclusion that the observed 32S/34S gradient is not an artifact but persists irrespective of the choice of sample and carbon isotope data. A gradient with rising 32S/34S values as a function of galactocentric radius implies that the solar system ratio should be larger than that of the local interstellar medium. With the new carbon isotope ratios, we indeed obtain a local 32S/34S isotope ratio about 10% below the solar system one, as expected in the case of decreasing 32S/34S ratios with time and increased amounts of stellar processing. However, taking older carbon isotope ratios based on a lesser amount of data, such a decrease is not seen. No systematic variation of 34S/33S ratios along galactocentric distance was found. The average value is 5.9{+/-}1.5, the error denoting the standard deviation of an individual measurement.2020ApJ...899..145Yhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/899/145CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/305/960 : Interstellar S isotopes (Chin+, 1996)J/A+A/308/573 : Ammonia on YSOs IRAS sources (Molinari+ 1996)J/A+A/451/1125 : Rotational excitation of CS (Lique+, 2006)J/ApJ/699/1153 : Kinematic distances GRS molecular clouds (Roman-Duval+, 2009)J/ApJ/741/110 : The BGPS. VII. Massive star-forming regions (Dunham+, 2011)J/MNRAS/418/1689 : Red MSX water maser and ammonia emissions (Urquhart+, 2011)J/A+A/544/A146 : ATLASGAL cold high-mass clumps with NH_3_ (Wienen+, 2012)J/ApJ/783/130 : Parallaxes of high mass star forming regions (Reid+, 2014)J/ApJ/822/59 : BGPS. XIV. Molecular cloud clumps GBT obs. (Svoboda+, 2016)J/A+A/606/A74 : IRC +10216 13.3GHz-18.5GHz spectrum (Zhang+, 2017)J/ApJ/885/131 : ~200 high-mass SFR plx & proper motion with VLBI (Reid+, 2019)J/ApJ/877/154 : H_2_CO TMRT obs. of Galactic molecular clouds (Yan+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/899/145https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/899/145http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/899/145https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/899/145https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/899/145http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/899/145GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/899/145/table1 (Observational parameters of CS and three of its rare isotopologues measured by the ARO 12m telescope)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/899/145/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/899/145/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/899/145/table1?GETtext/xml+votable180.050000true9.195833363.48394440.005555555555555556Cone search capability for table J/ApJ/899/145/table2 (Observational parameters of CS and three of its rare isotopologues measured by the IRAM 30m telescope)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/899/145/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/899/145/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/899/145/table2?GETtext/xml+votable180.050000true284.55258331.68069440.0055555555555555566/3011 3061 3649 14309 14314 14317 14353 14594 14611 14622 14655 14671 14689 14692 14704 15458 15473 15681 21439 23969 24189 24325 28830 28912 29091-29092 29094 29096 29101 29103 29113-29114 29461 29533 30245 30258-30259 30269 30312 30318-30319 30328 30405 30425 30617-30618 30622 30644 30691 30694 40612https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/899/145?format=asciiMillimeterdefaultJ/ApJ/899/145/table1Observational parameters of CS and three of its rare isotopologues measured by the ARO 12m telescopeIDSource identifiermeta.id;meta.maincharprimaryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000[0/23] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainSpeciesMolecular species identifiermeta.id;phys.molcharTime[8/88]? Integration timemintime.epochintnullableRMS[3/43]? Root Mean Square noise valuemKinstr.det.noiseintnullableDelV[0.48/0.96]? Channel widthkm/sspect.line.widthfloatnullableVLSR[-72.9/110] Local Standard of Rest velocitykm/sphys.veloc;pos.lsrfloate_VLSR[0/0.78] Uncertainty in LSRkm/sstat.error;phys.veloc;pos.lsrfloatDelV0.5[1.6/58.6] Linewidth; Full-Width at Half-Maximumkm/sobs.paramfloate_DelV0.5[0.0/1.39] Uncertainty in DelV0.5km/sstat.errorfloatInt[0.07/107.25] Integrated line intensityK.km/sphot.flux.densityfloate_Int[0.01/0.65] Uncertainty in IntK.km/sstat.errorfloatTmb[0.03/10.64] Peak beam brightness temperatureKphys.temperature;stat.maxfloatIRAMIndicates observations with IRAM (table2)meta.ref.urlcharSratioNumber of data on Sulfur isotopes ratio (table3)meta.numberintnullableJ/ApJ/899/145/table2Observational parameters of CS and three of its rare isotopologues measured by the IRAM 30m telescoperecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDSource identifiermeta.id;meta.maincharRAJ2000[2/19] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainSpeciesMolecular species identifiermeta.id;phys.molcharTime[9/38] Integration timemintime.epochintRMS[13/72] Root Mean Square noise valuemKinstr.det.noiseintDelV[0.6/0.6] Channel widthkm/sspect.line.widthfloatVLSR[-47.4/110] Local Standard of Rest velocitykm/sphys.veloc;pos.lsrfloate_VLSR[0/0.84] Uncertainty in LSRkm/sstat.error;phys.veloc;pos.lsrfloatDelV0.5[2.06/10.7] Linewidth Full-Width at Half-Maximumkm/sobs.paramfloate_DelV0.5[0.0/2.21] Uncertainty in DelV0.5km/sstat.errorfloatInt[0.48/96.13] Integrated line intensityK.km/sphot.flux.densityfloate_Int[0.03/0.33] Uncertainty in IntK.km/sstat.errorfloatTmb[0.04/12.76] Peak beam brightness temperatureKphys.temperature;stat.maxfloatJ/ApJ/899/145/table3Sulfur isotope ratios and CS, C34S and 13CS optical depthsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDSource identifiermeta.id;meta.maincharDSun[0.42/11.1]? Distance from the Sunkpcpos.distance;pos.heliocentricfloatnullableDGC[0/11.7]? Distance from the galactic centerkpcpos.distance;pos.galactocentricfloatnullable12C/13C[12/71]? The ^12^C/^13^C isotope ratio (1)stat.fit.omcintnullablee_12C/13C[7/14]? Uncertainty in 12C/13Cstat.errorintnullabletau12CS[0.3/11.5]? Estimated peak optical depth of ^12^CS (2)phys.absorption.opticalDepth;stat.maxfloatnullabletau13CS[0.004/0.271]? Estimated peak optical depth of ^13^CS (2)phys.absorption.opticalDepth;stat.maxfloatnullabletauC34S[0.009/0.627]? Estimated peak optical depth of C^34^S (2)phys.absorption.opticalDepth;stat.maxfloatnullable32S/34S[7.1/33.8] The ^32^S/^34^S isotope ratio (3)stat.fit.omcfloate_32S/34S[3.4/11.3] Uncertainty in 32S/34S (3)stat.errorfloat34S/33S[1.7/10.5] The ^34^S/^33^S isotope ratio (3)stat.fit.omcfloate_34S/33S[0.1/2.3] Uncertainty in 34S/33S (3)stat.errorfloatTk[18.0/98]? Gas kinetic temperatureKphys.temperaturefloatnullableARONumber of observation with ARO (table1)meta.numberintnullable