J/A+A/644/A160ivo://CDS.VizieR/J/A+A/644/A160doi:10.26093/cds/vizier.36440160CDSKim W.-J.Wyrowski F.Urquhart J.S.Perez-Beaupuits J.P.Pillai T.,Tiwari M.Menten K.M.2021-02-19T07:35:55Z2020-12-15T07:55:08ZCDS support team

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

cds-question@unistra.frsurveysinterstellar-mediumh-ii-regionsWe study ten molecular transitions obtained from an unbiased 3mm molecular line survey using the IRAM 30m telescope toward 409 compact dust clumps identified by the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) to better understand the photodissociation regions (PDRs) associated with these clumps. The main goal of this study is to investigate whether the abundances of the selected molecules show any variations resulting from the PDR chemistry in different clump environments. We selected HCO, HOC^+^, C_2_H, c-C_3_H_2_, CN, H^13^CN, HC^15^N, and HN^13^C as PDR tracers, and H^13^CO^+^ and C^18^O as dense gas tracers. By using estimated optical depths of C_2_H and H^13^CN and assuming optically thin emission for other molecular transitions, we derived the column densities of those molecules and their abundances. To assess the influence of the presence and strength of ultra- violet radiation, we compare abundances of three groups of the clumps: HII regions, infrared bright non-HII regions, and infrared dark non-HII regions. We detected C^18^O, H^13^CO^+^, C_2_H, c-C_3_H_2_, CN, and HN^13^C toward most of the observed dust clumps (detection rate >94%), and H^13^CN is also detected with a detection rate of 75%. On the other hand, HCO and HC^15^N show detection rates of 32% and 39%, respectively, toward the clumps, which are mostly associated with HII region sources: Detection rates of HCO and HC^15^N toward the HII regions are 66% and 79%. We find that the abundances of HCO, CN, C_2_H, and c-C_3_H_2_ decrease as the H_2_ column density increases, indicating high visual extinction, while those of high-density tracers (i.e., H^13^CO^+^ and HC^15^N) are constant. In addition, N(HCO)/N(H^13^CO^+^) ratios significantly decrease as H_2_ column density increases, and, in particular, 82 clumps have X(HCO)>=10^-10^ and N(HCO)/N(H^13^CO^+^)>~1, which are indications of far-ultraviolet (FUV) chemistry. This suggests the observed HCO abundances are likely associated with FUV radiation illuminating the PDRs. We also find that high N(c-C_3_H_2_)/N(C_2_H) ratios found for HII regions that have high HCO abundances (>~10^-10^) are associated with more evolved clumps with high L_bol_/M_clump_. This trend might be associated with gain-surface processes, which determine the initial abundances of these molecules, and time-dependent effects in the clumps corresponding to the envelopes around dense PDRs and HII regions. In addition, some fraction of the measured abundances of the small hydrocarbons of the HII sources may be the result of the photodissociation of PAH molecules.2020A&A...644A.160Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/644/A160CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/570/A65 : ATLASGAL massive clumps CO depletion (Giannetti+, 2014)J/A+A/586/A149 : SiO in ATLASGAL-selected massive clumps (Csengeri+, 2016)J/A+A/599/A139 : ATLASGAL massive clumps dust characterization (Koenig+, 2017)J/A+A/602/A37 : Millimeter RRL in ATLASGAL-selected massive clumps (Kim+ 2017)J/A+A/603/A33 : Temperature evolution in massive clumps (Giannetti+, 2017)J/A+A/611/A6 : ATLASGAL massive clumps H_2_CO data (Tang+, 2018)J/A+A/622/A135 : Mid-J CO emission of Top100 clumps (Navarete+, 2019)J/MNRAS/473/1059 : Complete sample of Galactic clump propertieshttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/644/A160https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/644/A160http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/644/A160https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/644/A160https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/644/A160http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/644/A160GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/644/A160/table2 (List of observed sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/644/A160/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/644/A160/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/644/A160/table2?GETtext/xml+votable180.050000true270.512083-23.8869440.0055555555555555565/3588 7278 7376 7383 7564 7579 7605 7654 6/12970 28912 28918-28919 29090-29091 29094 29097 29099-29101 29103 29116 29118-29119 29162 29460-29461 29463 29508-29510 29522 29526 29529 30218-30219 30223 30241 30244-30245 30262-30263 30268-30269 30312-30313 30315 30330 30405 30417 30419 30592 30595 30604 30606 30622-30623 30641 30644-30645 30691-30692 30694-30695 30701 30712 30714-30716 30719https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/644/A160?format=asciidefaultJ/A+A/644/A160/table2List of observed sourcesSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump name (AGAL LLL.lll+BB.bbb or GLLL.lll+B.bbb)meta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainDist? Distance of sourcekpcpos.distancefloatnullableTdust? Temperature of dustKphys.temperaturefloatnullableTypeClump type related with HII presencesrc.classcharClassClassification of clump typesrc.classcharComCommentsmeta.notecharJ/A+A/644/A160/t3cchLine parameters of hyperfine lines of CCHe_dvUncertainty on Line linewidthkm/sstat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharLineLine (1)meta.id;spect.linecharVlsrLSR velocity of Linekm/sphys.veloc;pos.lsrfloate_VlsrUncertainty on Line velocitykm/sstat.error;phys.veloc;pos.lsrfloatdvLine linewidthkm/sspect.line.widthfloatTautotalTotal optical thicknessphys.absorption.opticalDepthfloate_TautotalUncertainty on optical thicknessstat.errorfloatTmbPeak intensity of the Line (2)Kphot.flux;spect.linefloatrmsrms noise per channelKstat.stdev;instr.det.noisefloatJ/A+A/644/A160/t3h13cnLine parameters of hyperfine lines of H13CNe_VlsrUncertainty on Line velocitykm/sstat.error;phys.veloc;pos.lsrfloatdvLine linewidthkm/sspect.line.widthfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharLineLine (1)meta.id;spect.linecharVlsrLSR velocity of Linekm/sphys.veloc;pos.lsrfloate_dvUncertainty on Line linewidthkm/sstat.errorfloatTautotalTotal optical thicknessphys.absorption.opticalDepthfloate_TautotalUncertainty on optical thicknessstat.errorfloatTmbPeak intensity of the Line (2)Kphot.flux;spect.linefloatrmsrms noise per channelKstat.stdev;instr.det.noisefloatJ/A+A/644/A160/t4c-c3h2Gaussian line parameters of c-C3H2recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharLineLine (1)meta.id;spect.linecharAreaVelocity integrated intensityK.km/sspect.dopplerVeloc.radiofloate_AreaUncertainty of AreaK.km/sstat.error;phys.areafloatVlsrPeak velocity of Linekm/sphys.veloc;pos.lsrfloate_VlsrUncertainty of Line velocitykm/sstat.error;phys.veloc;pos.lsrfloatdvLine linewidthkm/sspect.line.widthfloate_dvUncertainty of Line linewidthkm/sstat.errorfloatTmbPeak intensity of LineKphot.flux;spect.linefloatrmsrms noise per channelKstat.stdev;instr.det.noisefloatJ/A+A/644/A160/t4c18oGaussian line parameters of C18Oe_VlsrUncertainty of Line velocitykm/sstat.error;phys.veloc;pos.lsrfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharLineLine (1)meta.id;spect.linecharAreaVelocity integrated intensityK.km/sspect.dopplerVeloc.radiofloate_AreaUncertainty of AreaK.km/sstat.error;phys.areafloatVlsrPeak velocity of Linekm/sphys.veloc;pos.lsrfloatdvLine linewidthkm/sspect.line.widthfloate_dvUncertainty of Line linewidthkm/sstat.errorfloatTmbPeak intensity of LineKphot.flux;spect.linefloatrmsrms noise per channelKstat.stdev;instr.det.noisefloatJ/A+A/644/A160/t4cnGaussian line parameters of CNrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharLineLine (1)meta.id;spect.linecharAreaVelocity integrated intensityK.km/sspect.dopplerVeloc.radiofloate_AreaUncertainty of AreaK.km/sstat.error;phys.areafloatVlsrPeak velocity of Linekm/sphys.veloc;pos.lsrfloate_VlsrUncertainty of Line velocitykm/sstat.error;phys.veloc;pos.lsrfloatdvLine linewidthkm/sspect.line.widthfloate_dvUncertainty of Line linewidthkm/sstat.errorfloatTmbPeak intensity of LineKphot.flux;spect.linefloatrmsrms noise per channelKstat.stdev;instr.det.noisefloatJ/A+A/644/A160/t4h13copGaussian line parameters of H13CO+recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharLineLine (1)meta.id;spect.linecharAreaVelocity integrated intensityK.km/sspect.dopplerVeloc.radiofloate_AreaUncertainty of AreaK.km/sstat.error;phys.areafloatVlsrPeak velocity of Linekm/sphys.veloc;pos.lsrfloate_VlsrUncertainty of Line velocitykm/sstat.error;phys.veloc;pos.lsrfloatdvLine linewidthkm/sspect.line.widthfloate_dvUncertainty of Line linewidthkm/sstat.errorfloatTmbPeak intensity of LineKphot.flux;spect.linefloatrmsrms noise per channelKstat.stdev;instr.det.noisefloatJ/A+A/644/A160/t4hc15nGaussian line parameters of HC15NrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharLineLine (1)meta.id;spect.linecharAreaVelocity integrated intensityK.km/sspect.dopplerVeloc.radiofloate_AreaUncertainty of AreaK.km/sstat.error;phys.areafloatVlsrPeak velocity of Linekm/sphys.veloc;pos.lsrfloate_VlsrUncertainty of Line velocitykm/sstat.error;phys.veloc;pos.lsrfloatdvLine linewidthkm/sspect.line.widthfloate_dvUncertainty of Line linewidthkm/sstat.errorfloatTmbPeak intensity of LineKphot.flux;spect.linefloatrmsrms noise per channelKstat.stdev;instr.det.noisefloatJ/A+A/644/A160/t4hcoGaussian line parameters of HCOrmsrms noise per channelKstat.stdev;instr.det.noisefloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharLineLine (1)meta.id;spect.linecharAreaVelocity integrated intensityK.km/sspect.dopplerVeloc.radiofloate_AreaUncertainty of AreaK.km/sstat.error;phys.areafloatVlsrPeak velocity of Linekm/sphys.veloc;pos.lsrfloate_VlsrUncertainty of Line velocitykm/sstat.error;phys.veloc;pos.lsrfloatdvLine linewidthkm/sspect.line.widthfloate_dvUncertainty of Line linewidthkm/sstat.errorfloatTmbPeak intensity of LineKphot.flux;spect.linefloatJ/A+A/644/A160/t4hn13cGaussian line parameters of HN13CrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharLineLine (1)meta.id;spect.linecharAreaVelocity integrated intensityK.km/sspect.dopplerVeloc.radiofloate_AreaUncertainty of AreaK.km/sstat.error;phys.areafloatVlsrPeak velocity of Linekm/sphys.veloc;pos.lsrfloate_VlsrUncertainty of Line velocitykm/sstat.error;phys.veloc;pos.lsrfloatdvLine linewidthkm/sspect.line.widthfloate_dvUncertainty of Line linewidthkm/sstat.errorfloatTmbPeak intensity of LineKphot.flux;spect.linefloatrmsrms noise per channelKstat.stdev;instr.det.noisefloatJ/A+A/644/A160/table6Column density of moleculesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameATLASGAL clump namemeta.id;meta.maincharN(C18O)? Column density of C18Ocm**-2phys.columnDensitydoublenullableN(HCO)? Column density of HCOcm**-2phys.columnDensitydoublenullableN(H13CO+)? Column density of H13CO+cm**-2phys.columnDensitydoublenullableN(CCH)? Column density of CCHcm**-2phys.columnDensitydoublenullableN(c-C3H2)? Column density of c-C3H2cm**-2phys.columnDensitydoublenullableN(CN)? Column density of CNcm**-2phys.columnDensitydoublenullableN(HC15N)? Column density of HC15Ncm**-2phys.columnDensitydoublenullableN(H13CN)? Column density of H13CNcm**-2phys.columnDensitydoublenullableN(HN13C)? Column density of HN13Ccm**-2phys.columnDensitydoublenullable