J/A+A/570/A65ivo://CDS.VizieR/J/A+A/570/A65doi:10.26093/cds/vizier.35700065CDSGiannetti A.Wyrowski F.Brand J.Csengeri T.Fontani F.,Walmsley C.M.Nguyen Luong Q.Beuther H.Schuller F.Guesten R.,Menten K.M.2017-10-12T12:59:50Z2014-12-04T13:56:11ZCDS support team

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

cds-question@unistra.frmolecular-cloudsinterstellar-mediumIn the low-mass regime, molecular cores have spatially resolved temperature and density profiles allowing a detailed study of their chemical properties. It is found that the gas-phase abundances of C-bearing molecules in cold starless cores rapidly decrease with increasing density. Here the molecules tend to stick to the grains, forming ice mantles. We study CO depletion in a large sample of massive clumps, and investigate its correlation with evolutionary stage and with the physical parameters of the sources. Moreover, we study the gradients in [^12^C]/[^13^C] and [^18^O]/[^17^O] isotopic ratios across the inner Galaxy, and the virial stability of the clumps. From the ATLASGAL 870{mu}m survey we selected 102 clumps, which have masses in the range ~10^2^-3x10^4^M_{sun}_, sampling different evolutionary stages. We use low-J emission lines of CO isotopologues and the dust continuum emission to infer the depletion factor f_D_. RATRAN one-dimensional models were also used to determine f_D_ and to investigate the presence of depletion above a density threshold. The isotopic ratios and optical depth were derived with a Bayesian approach. We find a significant number of clumps with a high degree of CO depletion, up to ~20. Larger values are found for colder clumps, thus for earlier evolutionary phases. For massive clumps in the earliest stages of evolution we estimate the radius of the region where CO depletion is important to be a few tenths of a pc. The value of the [^12^C]/[^13^C] ratio is found to increase with distance from the Galactic centre, with a value of ~66+/-12 for the solar neighbourhood. The [^18^O]/[^17^O] ratio is approximately constant (~4) across the inner Galaxy between 2kpc and 8kpc, albeit with a large range (~2-6). Clumps are found with total masses derived from dust continuum emission up to ~20 times higher than M_vir_, especially among the less evolved sources. These large values may in part be explained by the presence of depletion: if the CO emission comes mainly from the low-density outer layers, the molecules may be subthermally excited, leading to an overestimate of the dust masses. CO depletion in high-mass clumps seems to behave as in the low-mass regime, with less evolved clumps showing larger values for the depletion than their more evolved counterparts, and increasing for denser sources. The ratios [^12^C]/[^13^C] and [^18^O]/[^17^O] are consistent with previous determinations, and show a large intrinsic scatter.2014A&A...570A..65Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/570/A65CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/443/1555 : ATLASGAL massive star forming clumps sample (Urquhart+ 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/570/A65https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/570/A65http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/570/A65https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/570/A65https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/570/A65http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/570/A65GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/570/A65/samples (Distances and classification derived from C^17^O(3-2), and masses for the 3 subsamples S1 (tables A1 and A16), S2 (tables A2 and A17), and S3 (tables A3 and A18))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/570/A65/samples?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/570/A65/samples?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/570/A65/samples?GETtext/xml+votable180.050000true271.5972917-21.61811110.0055555555555555565/7278 10614 6/14353 28803 28919 29091 29097 29101 29116 29505 29508-29509 29529 29532 30218 30256 30258 30262 30268-30269 30318-30319 30405 30422 30618 30694 30716 41653 41655 41677 41685 41759 41767 41772 41776 41812 41814-41815 41820 42159 42168-42169 42172-42173 42211 42215 42224 42226-42227 42229-42230 42376 42378-42379 42381 42383 42387 42390 42392 42396 42398 42451 42455 42460-42461 42497-42498 42512 43013https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/570/A65?format=asciidefaultJ/A+A/570/A65/tablea13Molecular column densities for subsample S1 (^12^C^18^O, ^12^C^17^O,1-0, ^12^C^17^O,3-2, ^13^C^18^O, N_2_)GroupGroup (G1)meta.idcharSsub-samplemeta.idcharN(CO)^12^C^18^O molecular column density1e+16cm**-2phys.columnDensityfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/3]? Multiplicity index on Sourcemeta.code.multipintnullableb_N(CO)Lower value of 68% confidence level of N(^12^C^18^O)1e+16cm**-2stat.fit.paramfloatB_N(CO)Upper value of 68% confidence level of N(^12^C^18^O)1e+16cm**-2stat.fit.paramfloatN(1-0)^12^C^17^O molecular column density1e+15cm**-2phys.columnDensityfloatb_N(1-0)Lower value of 68% confidence level of N(^12^C^17^O,1-0)1e+15cm**-2stat.fit.paramfloatB_N(1-0)Upper value of 68% confidence level of N(^12^C^17^O,1-0)1e+15cm**-2stat.fit.paramfloatl_N(3-2)Limit flag on N(12C17O3-2)meta.code.errorcharN(3-2)^12^C^17^O molecular column density1e+15cm**-2phys.columnDensityfloatb_N(3-2)? Lower value of 68% confidence level of N(^12^C^17^O,3-2)1e+15cm**-2stat.fit.paramfloatnullableB_N(3-2)? Upper value of 68% confidence level of N(^12^C^17^O,3-2)1e+15cm**-2stat.fit.paramfloatnullablel_N(1318)Limit flag on N(13C18O)meta.code.errorcharN(1318)^13^C^18^O molecular column density1e+13cm**-2phys.columnDensityfloatb_N(1318)? Lower value of 68% confidence level of N(^13^C^18^O)1e+13cm**-2stat.fit.paramfloatnullableB_N(1318)? Upper value of 68% confidence level of N(^13^C^18^O)1e+13cm**-2stat.fit.paramfloatnullableN(H2)? H_2_ molecular column density1e+23cm**-2phys.columnDensityfloatnullableb_N(H2)? Lower value of 68% confidence level of N(H_2_)1e+23cm**-2stat.fit.paramfloatnullableB_N(H2)? Upper value of 68% confidence level of N(H_2_)1e+23cm**-2stat.fit.paramfloatnullablen_Group[)] ')' indicates classification of the main componentmeta.notecharJ/A+A/570/A65/tablea14Molecular column densities for subsample S2 (^12^C^18^O, ^12^C^17^O, H_2_)GroupGroup (G1)meta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSsub-samplemeta.idcharAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/4]? Multiplicity index on Sourcemeta.code.multipintnullableN(CO)^12^C^18^O molecular column density1e+16cm**-2phys.columnDensityfloatb_N(CO)Lower value of 68% confidence level of N(^12^C^18^O)1e+16cm**-2stat.fit.paramfloatB_N(CO)Upper value of 68% confidence level of N(^12^C^18^O)1e+16cm**-2stat.fit.paramfloatl_N(1217)Limit flag on N(12C17O)meta.code.errorcharN(1217)^12^C^18^O molecular column density1e+15cm**-2phys.columnDensityfloatb_N(1217)? Lower value of 68% confidence level of N(^12^C^17^O)1e+15cm**-2stat.fit.paramfloatnullableB_N(1217)? Upper value of 68% confidence level of N(^12^C^17^O)1e+15cm**-2stat.fit.paramfloatnullableN(H2)? H_2_ molecular column density1e+23cm**-2phys.columnDensityfloatnullableb_N(H2)? Lower value of 68% confidence level of N(H_2_)1e+23cm**-2stat.fit.paramfloatnullableB_N(H2)? Upper value of 68% confidence level of N(H_2_)1e+23cm**-2stat.fit.paramfloatnullablen_Group[)] ')' indicates classification of the main componentmeta.notecharJ/A+A/570/A65/tablea5Line parameters of C^18^O(1-0) for subsample S1recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSsub-samplemeta.idcharAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/3]? Multiplicity index on Sourcemeta.code.multipintnullableT.dV? CO(1-0) isotope integrated fluxK.km/sspect.line.intensityfloatnullableTmb? CO(1-0) isotope main beam temperatureKphys.temperature;meta.mainfloatnullablee_TmbCO(1-0) isotope rms noiseKstat.errorfloatVLSR? CO(1-0) isotope LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR? rms uncertainty on VLSRkm/sstat.error;phys.veloc;pos.lsrfloatnullableDV? CO(1-0) isotope {delta}Vkm/sphys.veloc;arith.difffloatnullablee_DV? rms uncertainty on DVkm/sstat.errorfloatnullableJ/A+A/570/A65/tablea15Molecular column densities for subsample S3 (^12^C^17^O, H_2_)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSsub-samplemeta.idcharAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharN(1217)^12^C^17^O molecular column density1e+15cm**-2phys.columnDensityfloatb_N(1217)Lower value of 68% confidence level of N(^12^C^17^O)1e+15cm**-2stat.fit.paramfloatB_N(1217)Upper value of 68% confidence level of N(^12^C^17^O)1e+15cm**-2stat.fit.paramfloatN(H2)H_2_ molecular column density1e+23cm**-2phys.columnDensityfloatb_N(H2)Lower value of 68% confidence level of N(H_2_)1e+23cm**-2stat.fit.paramfloatB_N(H2)Upper value of 68% confidence level of N(H_2_)1e+23cm**-2stat.fit.paramfloatGroupGroup (G1)meta.idcharJ/A+A/570/A65/samplesDistances and classification derived from C^17^O(3-2), and masses for the 3 subsamples S1 (tables A1 and A16), S2 (tables A2 and A17), and S3 (tables A3 and A18)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSsub-samplemeta.idcharAllDisplay data for this source from all the tablesmeta.ref.urlcharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainVLSRLSR velocitykm/sphys.veloc;pos.lsrfloatDnearNear distancekpcpos.distance;pos.heliocentricfloatznearHeight above the Galactic plane for the near distancepcpos.cartesian.z;pos.galacticfloatDfar? Far distancekpcpos.distance;pos.heliocentricfloatnullablezfar? Height above the Galactic plane for the far distancepcpos.cartesian.z;pos.galacticfloatnullableHI[TNF-] Distance ambiguity resolution from Wienen et al., in prep: T=tangent, N=near, F=farmeta.codecharDlit? Literature values for the distancekpcpos.distance;pos.heliocentricfloatnullabler_Dlit? Reference for Dlit (2)meta.ref;pos.frameintnullableMetMethod Method with which the distance Dlit was determined (3)meta.notecharDistAdopted distancekpcpos.distance;pos.heliocentricfloatDGCResulting Galactocentric distancekpcpos.distancefloatGroupSource classification (G1)meta.idcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharprimarym_AGAL[1/3]? Multiplicity index on Sourcemeta.code.multipintnullableMassMassksolMassphys.massfloatb_MassLower value of 68% confidence level of MassksolMassstat.fit.paramfloatB_MassUpper value of 68% confidence level of MassksolMassstat.fit.paramfloatMvirViral massksolMassphys.massfloatb_MvirLower value of 68% confidence level of MvirksolMassstat.fit.paramfloatB_MvirUpper value of 68% confidence level of MvirksolMassstat.fit.paramfloatSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/570/A65/tablea4Line parameters of of C^17^O(1-0) and C^17^O(3-2) for subsample S1Ssub-samplemeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/3]? Multiplicity index on Sourcemeta.code.multipintnullableT.dV1C^17^O(1-0) integrated fluxK.km/sspect.line.intensityfloatTmb1C^17^O(1-0) main beam temperatureKphys.temperature;instr.beamfloate_Tmb1C^17^O(1-0) rms noiseKstat.errorfloatVLSR1C^17^O(1-0) LSR velocitykm/sphys.veloc;pos.lsrfloate_VLSR1rms uncertainty on VLSR1km/sstat.errorfloatDV1C^17^O(1-0) {delta}Vkm/sphys.veloc;arith.difffloate_DV1rms uncertainty on DV1km/sstat.errorfloatT.dV2? C^17^O(3-2) integrated fluxK.km/sspect.line.intensityfloatnullableTmb2? C^17^O(3-2) main beam temperatureKphys.temperature;instr.beamfloatnullablee_Tmb2C^17^O(3-2) rms noiseKstat.errorfloatVLSR2? C^17^O(3-2) LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR2? rms uncertainty on VLSR2km/sstat.errorfloatnullableDV2? C^17^O(3-2) {delta}Vkm/sphys.veloc;arith.difffloatnullablee_DV2? rms uncertainty on DV2km/sstat.errorfloatnullableJ/A+A/570/A65/tablea6Line parameters of ^13^CO(1-0) for subsample S1recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSsub-samplemeta.idcharAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/3]? Multiplicity index on Sourcemeta.code.multipintnullableT.dV? CO(1-0) isotope integrated fluxK.km/sspect.line.intensityfloatnullableTmb? CO(1-0) isotope main beam temperatureKphys.temperature;meta.mainfloatnullablee_TmbCO(1-0) isotope rms noiseKstat.errorfloatVLSR? CO(1-0) isotope LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR? rms uncertainty on VLSRkm/sstat.error;phys.veloc;pos.lsrfloatnullableDV? CO(1-0) isotope {delta}Vkm/sphys.veloc;arith.difffloatnullablee_DV? rms uncertainty on DVkm/sstat.errorfloatnullableJ/A+A/570/A65/tablea7Line parameters of ^13^C^18^O(1-0) for subsample S1recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSsub-samplemeta.idcharAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/3]? Multiplicity index on Sourcemeta.code.multipintnullableT.dV? CO(1-0) isotope integrated fluxK.km/sspect.line.intensityfloatnullableTmb? CO(1-0) isotope main beam temperatureKphys.temperature;meta.mainfloatnullablee_TmbCO(1-0) isotope rms noiseKstat.errorfloatVLSR? CO(1-0) isotope LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR? rms uncertainty on VLSRkm/sstat.error;phys.veloc;pos.lsrfloatnullableDV? CO(1-0) isotope {delta}Vkm/sphys.veloc;arith.difffloatnullablee_DV? rms uncertainty on DVkm/sstat.errorfloatnullableJ/A+A/570/A65/tablea8Line parameters of C^18^O(2-1) and C^17^O(3-2) for subsample S2recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSsub-samplemeta.idcharAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/4]? Multiplicity index on Sourcemeta.code.multipintnullableT.dV1? C^18^O(2-1) integrated fluxK.km/sspect.line.intensityfloatnullableTmb1? C^18^O(2-1) main beam temperatureKphys.temperature;instr.beamfloatnullablerms1? C^18^O(2-1) rms noiseKstat.snr;instr.det.noisefloatnullableVLSR1? C^18^O(2-1) LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR1? rms uncertainty on VLSR1km/sstat.errorfloatnullableDV1? C^18^O(2-1) {delta}Vkm/sphys.veloc;arith.difffloatnullablee_DV1? rms uncertainty on DV1km/sstat.errorfloatnullabletau1? C^18^O(2-1) optical depthphys.absorption.opticalDepthfloatnullableb_tau2? Lower value of 68% confidence level of C^18^O(2-1) optical depthstat.fit.paramfloatnullableB_tau2? Upper value of 68% confidence level of C^18^O(2-1) optical depthstat.fit.paramfloatnullableT.dV2? C^17^O(3-2) integrated fluxK.km/sspect.line.intensityfloatnullableTmb2? C^17^O(3-2) main beam temperatureKphys.temperature;instr.beamfloatnullablee_Tmb2C^17^O(3-2) rms noiseKstat.errorfloatVLSR2? C^17^O(3-2) LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR2? rms uncertainty on VLSR2km/sstat.errorfloatnullableDV2? C^17^O(3-2) {delta}Vkm/sphys.veloc;arith.difffloatnullablee_DV2? rms uncertainty on DV2km/sstat.errorfloatnullabletau2? C^17^O(3-2) Optical depthphys.absorption.opticalDepthfloatnullablee_tau2? rms uncertainty on tau2stat.errorfloatnullableJ/A+A/570/A65/tablea9Line parameters of C^17^O(3-2) for subsample S3Ssub-samplemeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/4]? Multiplicity index on Sourcemeta.code.multipintnullableT.dV1? C^18^O(2-1) integrated fluxK.km/sspect.line.intensityfloatnullableTmb1? C^18^O(2-1) main beam temperatureKphys.temperature;instr.beamfloatnullablerms1? C^18^O(2-1) rms noiseKstat.snr;instr.det.noisefloatnullableVLSR1? C^18^O(2-1) LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR1? rms uncertainty on VLSR1km/sstat.errorfloatnullableDV1? C^18^O(2-1) {delta}Vkm/sphys.veloc;arith.difffloatnullablee_DV1? rms uncertainty on DV1km/sstat.errorfloatnullabletau1? C^18^O(2-1) optical depthphys.absorption.opticalDepthfloatnullableb_tau2? Lower value of 68% confidence level of C^18^O(2-1) optical depthstat.fit.paramfloatnullableB_tau2? Upper value of 68% confidence level of C^18^O(2-1) optical depthstat.fit.paramfloatnullableT.dV2? C^17^O(3-2) integrated fluxK.km/sspect.line.intensityfloatnullableTmb2? C^17^O(3-2) main beam temperatureKphys.temperature;instr.beamfloatnullablee_Tmb2C^17^O(3-2) rms noiseKstat.errorfloatVLSR2? C^17^O(3-2) LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_VLSR2? rms uncertainty on VLSR2km/sstat.errorfloatnullableDV2? C^17^O(3-2) {delta}Vkm/sphys.veloc;arith.difffloatnullablee_DV2? rms uncertainty on DV2km/sstat.errorfloatnullabletau2? C^17^O(3-2) Optical depthphys.absorption.opticalDepthfloatnullablee_tau2? rms uncertainty on tau2stat.errorfloatnullableJ/A+A/570/A65/texExcitation temperature for subsample S1 (tablea10) and S2 (tablea11)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSSub-sample nubmermeta.idcharAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/4]? Multiplicity index on Sourcemeta.code.multipintnullableTexExcitation temperatureKphys.atmol.excitationfloatn_Tex[*] Note on Tex (1)meta.notecharb_TexLower value of 68% confidence level of TexKstat.fit.paramfloatB_TexUpper value of 68% confidence level of TexKstat.fit.paramfloatGroupGroup (G1)meta.idcharn_Group[)] ')' indicates classification of the main componentmeta.notecharJ/A+A/570/A65/tablea12Optical depths and isotopic ratios for subsample S1l_tau2Limit flag on tau2meta.code.errorcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSsub-samplemeta.idcharAllDisplay data for this source from all the tablesmeta.ref.urlcharAGALAGAL source name (LLLL.lll+BB.bbb)meta.id;meta.maincharm_AGAL[1/3]? Multiplicity index on Sourcemeta.code.multipintnullablel_tau1Limit flag on tau1meta.code.errorchartau1C^18^O(1-0) optical depthphys.absorption.opticalDepthfloatb_tau1? Lower value of 68% confidence level of tau1stat.fit.paramfloatnullableB_tau1? Upper value of 68% confidence level of tau1stat.fit.paramfloatnullabletau2C^17^O(1-0) optical depthphys.absorption.opticalDepthfloatb_tau2? Lower value of 68% confidence level of tau2stat.fit.paramfloatnullableB_tau2? Upper value of 68% confidence level of tau2stat.fit.paramfloatnullable18/17OIsotopic ratio [^18^O]/[^17^O]phys.abundfloatb_18/17OLower value of 68% confidence level of isotopic ratio [^18^O]/[^17^O]stat.fit.paramfloatB_18/17OUpper value of 68% confidence level of isotopic ratio [^18^O]/[^17^O]stat.fit.paramfloat12/13CIsotopic ratio [^12^C]/[^13^C]phys.abundfloatb_12/13CLower value of 68% confidence level of isotopic ratio [^12^C]/[^13^C]stat.fit.paramfloatB_12/13CUpper value of 68% confidence level of isotopic ratio [^12^C]/[^13^C]stat.fit.paramfloat1217/1318Isotopic ratio [^12^C^17^O]/[^13^C^18^O]phys.abundfloatb_1217/1318Lower value of 68% confidence level of isotopic ratio [^12^C^17^O]/[^13^C^18^O]stat.fit.paramfloatB_1217/1318Upper value of 68% confidence level of isotopic ratio [^12^C^17^O]/[^13^C^18^O]stat.fit.paramfloat