J/ApJS/275/35ivo://CDS.VizieR/J/ApJS/275/35doi:10.26093/cds/vizier/bb-8k-13CDSSun Y.Yang JiYan Q.-Z.Zhang S.Su Y.Chen X.Zhou X.Ma Y.,Yuan L.2026-08-03T07:25:48Z2025-11-19T13:55:14ZCDS support team

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

cds-question@unistra.frmolecular-cloudsmilky-way-galaxyco-line-emissiongalaxy-kinematicsinterstellar-mediumWe present a catalog of 32162 ^12^CO molecular clouds that covers the northern outer Galactic plane (l=[15{deg},165{deg}] and l=[195{deg},230{deg}], and b=[-5.25{deg},+5.25{deg}]). The catalog was produced using a DBSCAN algorithm applied to the Milky Way Imaging Scroll Painting project data. We systematically analyze both the integrated properties and scaling relationships of these molecular clouds across different Galactocentric radii (8<R_GC_<26kpc). An interesting finding is that each cloud property's mean, median, and maximum values generally decrease systematically with increasing R_GC_, approximated quantitatively by exponential functions. The mass and size spectra for the entire sample show power-law indices of {gamma}=-2.00{\pm}0.13 and an upper mass limit of M_0_=(4.5{\pm}2.8)x10^6^M_{sun}_, and {gamma}=-3.68{\pm}0.48 with an upper size limit of R_0_=144{\pm}80pc, respectively. These spectra exhibit steeper slopes and reduced upper limits as R_GC_ increases. The derived scaling relations are M=12.00R_eff_^2.41^+/-0.003^, {sigma}_v_=0.25R_eff_^0.66+/-0.003^, and {alpha}_vir_=37.2M^-0.40+/-0.002^ for the whole outer Galaxy clouds. These scaling relations show slightly steeper correlations observed in more distant locations and notably deviate from Larson's relations. We find that 44.3% of the molecular mass resides in gravitationally bound structures, a proportion significantly higher than systematic studies from the CfA survey and external galaxies. Moreover, comparisons among different RGC subsamples also reveal a decrease in the amount of bound mass with increasing RGC. The scale length of the molecular disk is estimated to be approximately 2kpc. These results, based on a constant CO conversion factor of X_CO_=2.0x10^20^cm^-2^(K.km.s^-1^)^-1^, may be slightly altered by variations in XCO. In summary, our findings provide robust evidence for the influence of Galactic evolution on molecular cloud properties, at least in the outer Galaxy region studied.2024ApJS..275...35Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/275/35CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/275/67 : Velocity Field of the outer Galaxy (Brand+ 1993)J/A+A/327/325 : Distances of molecular cloud (May+, 1997)J/ApJ/551/852 : FCRAO CO survey of the outer Galaxy (Heyer+, 2001)J/ApJS/144/47 : Outer galaxy molecular cloud catalog (Brunt+, 2003)J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)J/ApJS/182/131 : Molecular clouds and clumps in the GRS (Rathborne+, 2009)J/ApJ/723/492 : Physical data of GRS molecular clouds (Roman-Duval+, 2010)J/ApJ/734/65 : CI radial velocities with HST/STIS (Jenkins+, 2011)J/A+A/542/A108 : Giant molecular clouds in M33 (Gratier+, 2012)J/ApJ/784/3 : The PAWS cat. of GMCs and islands in M51 (Colombo+, 2014)J/A+A/566/A37 : Iron abundances for 42 Galactic Cepheids (Genovali+, 2014)J/AJ/147/46 : Properties of clumps in the NAN complex (Zhang+, 2014)J/ApJ/798/L27 : CO obs. of molecular clouds in the 2nd quadrant (Sun+, 2015)J/A+A/594/A116 : HI4PI spectra and column density maps (HI4PI team+, 2016)J/ApJ/833/229 : Star forming cloud-giant molecular clouds (Lee+, 2016)J/A+A/585/A150 : On the metallicity of open clusters. III. (Netopil+, 2016)J/ApJ/834/57 : MW molecular clouds from ^12^CO (Miville-Deschenes+, 2017)J/MNRAS/470/2539 : Radiation fields of the Milky Way (Popescu+, 2017)J/A+A/601/A124 : Clouds in SEDIGISM field (Schuller+, 2017)J/ApJS/230/17 : CO obs. of MCs in the Extreme Outer Gal. region (Sun+, 2017)J/A+A/598/A30 : Massive star forming molecular clumps Tkin (Tang+, 2017)J/ApJ/857/19 : ALMA view of GMCs in NGC 300 (Faesi+, 2018)J/ApJ/860/172 : Cloud-scale molecular gas in 15 galaxies (Sun+, 2018)J/A+A/611/A6 : ATLASGAL massive clumps H_2_CO data (Tang+, 2018)J/MNRAS/473/1059 : Complete sample of Gal. clump properties (Urquhart+, 2018)J/ApJS/241/1 : Surveys of clumps & cores in Cygnus X. I. (Cao+, 2019)J/MNRAS/483/4291 : Properties of JCMT CO(3-2) molecular clouds (Colombo+, 2019)J/ApJ/885/131 : High-mass SFR plx & proper motion with VLBI (Reid+, 2019)J/A+A/632/A58 : Physical properties of CHIMPS clumps (Rigby+, 2019)J/ApJ/887/114 : VLA ~8-10GHz obs. of WISE Gal. HII regions (Wenger+, 2019)J/A+A/633/A147 : FQS. Galactic Plane CO survey (Benedettini+, 2020)J/ApJ/901/L8 : Molecular gas properties of 70 PHANGS-ALMA gal. (Sun+, 2020)J/A+A/654/A144 : 13CO (1-0) data molecular cloud cat. (Benedettini+, 2021)J/MNRAS/500/3027 : The SEDIGISM survey: molecular clouds (Duarte-Cabral+, 2021)J/ApJS/257/43 : PHANGS-ALMA: CO(2-1) imaging of gal. (Leroy+, 2021)J/ApJS/252/20 : CO survey of the CMa OB1 complex (Lin+, 2021)J/MNRAS/505/4048 : WISDOM Project IX study of GMCs in NGC 4429 (Liu+, 2021)J/ApJS/254/3 : CO obs. of molecular clouds in the MW midplane (Ma+, 2021)J/MNRAS/500/3064 : The SEDIGISM survey: First Data Release (Schuller+, 2021)J/ApJS/252/1 : OH and HI data in molecular clouds (Tang+, 2021)J/A+A/658/A54 : Molecular cloud assoc. to MW spiral arms (Colombo+, 2022)J/MNRAS/510/3389 : High-mass star formation evol. trends (Urquhart+, 2022)J/ApJS/268/1 : Mol. clouds CO obs. in the 3rd Gal. quadrant (Dong+, 2023)J/AJ/165/106 : Mol. clouds in section of 3rd Gal. quadrant (Wang+, 2023)J/AJ/167/228 : Physical properties of 221 clumps (Luo+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/275/35https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/275/35http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/275/35https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/275/35https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/275/35http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/275/35GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/275/35/table1 (Molecular clouds in the Outer Galaxy identified from the MWISP survey)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/275/35/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/275/35/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/275/35/table1?GETtext/xml+votable180.050000true274.18766-15.737570.0055555555555555563/223 4/91 111-114 120 122 190-191 197 199 204-206 227-228 232 890-891 896-897 900 913 915 918-919 961 964-965 976-977 980 1354-1355 1377 1379 1382 1388 1390 1477 1479 1891 1901 5/355 358-359 361 363 370 437 439 460 462 484 751 755-757 759 785 787 792-793 795 814-815 828-829 832 834 840 842 899 901-903 907 922 932 934 936-938 3242-3243 3515 3518-3519 3547 3550-3551 3558-3559 3604 3606-3609 3612-3614 3650-3651 3656-3657 3659 3666-3667 3670-3671 3841-3843 3848-3850 3852-3853 3864-3865 3868-3869 3912-3913 3916-3917 3924-3925 5385-5387 5408 5410-5412 5414-5415 5434 5505 5507 5520 5522 5541 5543 5549 5556 5558 5564 5566-5567 5904-5905 5907 5915 5940-5941 5960 5963 5984 7279 7365 7376-7377 7380 7382-7383 7388 7561 7578-7579 7650-7651 7660-7661 7674-7675 7678-7679 8020-8021 6/1430-1431 1449-1451 1473-1475 1504-1506 1512 1621 1623 1629 1631 1652-1653 1655 1659 1661-1663 1743 1745-1747 1754 1765 1767 1773-1775 1844 1946 1968 1970 2911 2933 2938-2939 2999 3001-3003 3015 3019 3032-3033 3035 3133 3137 3176-3177 3179 3221 3223 3229-3231 3245-3247 3253-3254 3320-3322 3326 3333-3335 3340 3342 3364 3456 3464 3466 3593-3595 3601-3603 3616-3617 3619 3621-3623 3625-3627 3664-3666 3672-3674 3680 3682-3684 3686-3687 3692 3732-3734 3742 3756-3757 3760-3762 12963 12966 12984 12986-12988 12990 13034-13035 13038-13039 13050 13219 13226 13242-13243 13245 13303 13309 13986 13995 13998-13999 14003 14010-14014 14050 14053 14057-14059 14064 14068 14071 14186-14187 14194-14198 14218-14219 14222-14223 14227-14228 14230-14231 14385 14387 14389-14391 14396-14397 14399 14420 14422-14423 14440 14444-14446 14460-14461 14592-14593 14595 14597-14599 14632-14633 14658 14661 14674 14677-14679 14725 14736-14737 14740 14784 14788-14789 14800-14801 14804 15361-15363 15404-15405 15407 15416-15418 15420-15422 15464-15465 15468-15469 15480-15481 15484-15485 15656-15657 15660 15704-15705 15708 15712-15714 15716 20855 20861 20863 20949 20951 20957 20959 20981 21538-21539 21554-21555 21558 21560-21562 21564 21636-21637 21639 21652 21654 21728 21731-21732 22017 22019 22052-22053 22055 22061 22063 22095 22136 22138 22143 22149 22160-22161 22163 22169 22171 22193 22205-22206 22228 22230 22237 22260-22262 22408 22410 22442 23573 23624-23625 23627 23649 23651-23653 23655 23657 23659 23748-23749 23751 23757 23768-23769 23772-23773 23808 23810-23811 23816 23818-23819 23822-23823 23846-23848 23850-23851 23856 23858 23864 23866 23940-23941 23943 23952 29155 29162-29166 29457 29459 29468 29495 29512-29514 29516-29518 29526 29536 29541 29556-29557 30216 30218-30219 30222 30239-30241 30243 30248-30250 30253 30255 30282 30306 30322 30330 30335 30341 30352-30353 30356 30400-30401 30403-30406 30410 30453 30461 30506 30592 30594-30595 30598-30599 30610 30614 30616 30618-30620 30622-30626 30628-30630 30648-30649 30652-30653 30655 30688 30690-30691 30693-30695 30705-30706 30710 32065 32069 32092-32093https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/275/35?format=asciiRadiodefaultJ/ApJS/275/35/table1Molecular clouds in the Outer Galaxy identified from the MWISP surveyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/32162] Internal index numbermeta.id;meta.mainintGLON[15/230] Cloud centroid galactic longitudedegpos.galactic.lonindexedGLAT[-5.2/5.2] Cloud centroid galactic latitudedegpos.galactic.latindexedVelc[-123.2/86.3] Cloud centroid Local Standard of Rest velocitykm/sphys.veloc;pos.lsrfloatsigmaV[0.1/5.4] Velocity dispersionkm/sphys.veloc.dispersionfloatGLONpk[15/230] Peak CO emission galactic longitudedegpos.galactic.lonGLATpk[-5.2/5.3] Peak CO emission galactic latitudedegpos.galactic.latfloatVelpk[-123/87] Peak CO emission Local Standard of Rest velocitykm/sphys.veloc;pos.lsr;stat.maxfloatTpk[1/48.8] Peak CO emission main-beam temperatureKphys.temperature;em.line.CO;stat.maxfloatArea[1/38544] Angular area of cloudarcmin**2phys.angAreafloatFlux[0.4/388803] Total cloud fluxK.km.s**-1.arcmin**2phot.flux.density;em.line.COdoubleDist[0.8/22.5] Heliocentric distancekpcpos.distancefloatRGC[8.1/26.7] Galactocentric distancekpcpos.distance;pos.galactocentricfloatReff[0.2/101.4] Cloud effective radiuspcphys.size.radiusfloatTex[3.9/52.3] Cloud excitation temperatureKphys.temperature;em.line.COfloatMass[0.3/2545399] Cloud masssolMassphys.massdoubleSigmaMC[1.3/82] Cloud mass surface densitysolMass.pc**-2phys.densityfloatalphaVir[0.4/141] Cloud virial parameterphys.mass;arith.ratiofloatnH2[3/381] Cloud mean H_2_ number densitycm**-3meta.number;phys.density;stat.meanfloat_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.raindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decindexedPint/kB[30/377087.4] Cloud internal pressureK.cm**-3phys.pressuredoubleResCloud resolved? (1)meta.codechar