J/ApJ/853/175ivo://CDS.VizieR/J/ApJ/853/175doi:10.26093/cds/vizier.18530175CDSNaslim N.Tokuda K.Onishi T.Kemper F.Wong T.Morata O.Takada S.,Harada R.Kawamura A.Saigo K.Indebetouw R.Madden S.C.Hony S.,Meixner M.2025-05-22T20:11:23Z2023-10-09T10:16:59ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsmolecular-cloudsinterstellar-mediumco-line-emissionmillimeter-astronomysubmillimeter-astronomygalaxy-kinematicsyoung-stellar-objectsWe present the molecular cloud properties of N55 in the Large Magellanic Cloud using ^12^CO(1-0) and ^13^CO(1-0) observations obtained with Atacama Large Millimeter Array. We have done a detailed study of molecular gas properties, to understand how the cloud properties of N55 differ from Galactic clouds. Most CO emission appears clumpy in N55, and molecular cores that have young stellar objects (YSOs) show larger linewidths and masses. The massive clumps are associated with high and intermediate mass YSOs. The clump masses are determined by local thermodynamic equilibrium and virial analysis of the ^12^CO and ^13^CO emissions. These mass estimates lead to the conclusion that (a) the clumps are in self-gravitational virial equilibrium, and (b) the ^12^CO(1-0)-to-H_2_ conversion factor, X_CO_, is 6.5x10^20^cm^-2^ (K.km/s)^-1^. This CO-to-H_2_ conversion factor for N55 clumps is measured at a spatial scale of ~0.67pc, which is about two times higher than the X_CO_ value of the Orion cloud at a similar spatial scale. The core mass function of N55 clearly show a turnover below 200M_{sun}_, separating the low-mass end from the high-mass end. The low-mass end of the ^12^CO mass spectrum is fitted with a power law of index 0.5+/-0.1, while for ^13^CO it is fitted with a power law index 0.6+/-0.2. In the high-mass end, the core mass spectrum is fitted with a power index of 2.0+/-0.3 for ^12^CO, and with 2.5+/-0.4 for ^13^CO. This power law behavior of the core mass function in N55 is consistent with many Galactic clouds.2018ApJ...853..175Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/853/175CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/39 : Composite CO Survey of the Milky Way (Dame+ 1987)J/ApJS/110/21 : Molecular clouds in Cepheus and Cassiopeia (Yonekura+ 1997)J/ApJ/551/852 : FCRAO CO survey of the outer Galaxy (Heyer+, 2001)J/ApJ/639/259 : Sub-mm clumps in Orion B South MoC (Johnstone+, 2006)J/AJ/132/2268 : SAGE calibration stars (Meixner+, 2006)J/ApJ/665/1194 : Dense cores in the Orion A cloud survey (Ikeda+, 2007)J/ApJS/178/56 : CO observations of LMC Giant Molecular clouds (Fukui+, 2008)J/ApJ/686/948 : CO in extragalactic giant molecular clouds (Bolatto+, 2008)J/ApJ/691/1560 : Dense core survey in the Orion B cloud (Ikeda+, 2009)J/ApJ/695/511 : Young massive stars in LHA 120-N 44 (Chen+, 2009)J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)J/ApJS/184/172 : High- and intermediate-mass YSOs in the LMC (Gruendl+, 2009)J/ApJS/197/16 : CO observations of LMC molecular clouds (MAGMA). (Wong+, 2011)J/ApJS/202/4 : Planck cold clumps survey in the Orion complex (Liu+, 2012)J/ApJ/774/73 : ALMA CO observations of 30 Dor (Indebetouw+, 2013)J/ApJ/784/3 : The PAWS catalogs of GMCs and islands in M51 (Colombo+, 2014)J/AJ/148/124 : Herschel key program Heritage (Seale+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/853/175https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/853/175http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/853/175https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/853/175https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/853/175http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/853/175GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/853/175/table2 (Positions of identified YSOs and associated clumps)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/853/175/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/853/175/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/853/175/table2?GETtext/xml+votable180.050000true83.027-66.42580.005555555555555556Cone search capability for table J/ApJ/853/175/clumps (^12^CO(1-0) (Table 3) and ^13^CO(1-0) (Table 4) clump (dendrogram trunks) properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/853/175/clumps?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/853/175/clumps?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/853/175/clumps?GETtext/xml+votable180.050000true83.1367-66.45430.005555555555555556Cone search capability for table J/ApJ/853/175/cores (^13^CO(1-0) (Table 5) and ^12^CO(1-0) (Table 6) core (dendrogram leaves) properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/853/175/cores?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/853/175/cores?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/853/175/cores?GETtext/xml+votable180.050000true83.1354-66.45860.0055555555555555566/33113https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/853/175?format=asciiMillimeterRadiodefaultJ/ApJ/853/175/table2Positions of identified YSOs and associated clumpsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/15]? Running sequence numbermeta.id;meta.mainintnullablef_SeqFlag on Seq (1)meta.codecharRAYdeg? YSO right ascension (J2000)degpos.eq.ranullableDEYdeg? YSO declination (J2000)degpos.eq.decnullableRAJ2000Associated clump right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Associated clump declination (J2000)degpos.eq.dec;meta.mainClump[2/125]? ^13^CO clump number ID from Table 5meta.idintnullablef_Clump[*] *: Clump identified in ^12^CO emission but not in ^13^COmeta.codecharJ/ApJ/853/175/clumps^12^CO(1-0) (Table 3) and ^13^CO(1-0) (Table 4) clump (dendrogram trunks) propertiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMol^12^CO(1-0) (Table 3) or ^13^CO(1-0) (Table 4)meta.id;phys.molcharSeq[1/57] Running sequence numbermeta.id;meta.mainintRAJ2000[82.9/83.2] Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-66.5/-66.3] Declination (J2000)degpos.eq.dec;meta.mainRad[0.5/4.3] Radiuspcphys.size.radiusfloate_Rad[0.1/0.6] Rad uncertaintypcstat.errorfloatSigv[0.2/2.4] Velocity dispersion, {sigma}_V_km/sphys.veloc.dispersionfloate_Sigv[0.1/0.6] Sigv uncertaintykm/sstat.errorfloatVel[276/294] Velocitykm/sphys.veloc;pos.heliocentricfloatLCO[0.9/2958] CO luminosityK.km.s**-1.pc**-2phys.luminosity;em.radiofloate_LCO[0.1/9] LCO uncertaintyK.km.s**-1.pc**-2stat.errorfloatTpk[0.9/40] TemperatureKphys.temperaturefloatMvir[46/21824] Virial masssolMassphys.massinte_Mvir[30/550] Mvir uncertaintysolMassstat.errorintNH2[1/27]? H_2_ column density (only for Table 4)1e+21cm**-2phys.columnDensityfloatnullableMLTE[66/28278]? LTE mass (only for Table 4)solMassphys.massintnullablee_MLTE[15/78]? MLTE uncertaintysolMassstat.errorintnullableJ/ApJ/853/175/cores^13^CO(1-0) (Table 5) and ^12^CO(1-0) (Table 6) core (dendrogram leaves) propertiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMol^13^CO(1-0) (Table 5) or ^12^CO(1-0) (Table 6)meta.id;phys.molcharSeq[1/121] Running sequence numbermeta.id;meta.mainintRAJ2000[82.9/83.2] Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-66.5/-66.3] Declination (J2000)degpos.eq.dec;meta.mainRad[0.4/2] Radiuspcphys.size.radiusfloatSigV[0.1/2] Velocity dispersion, {sigma}_V_km/sphys.veloc.dispersionfloatVel[275/294] Velocitykm/sphys.veloc;pos.heliocentricfloatLCO[0.2/124] CO luminosityK.km.s**-1.pc**-2phys.luminosity;em.radiofloatMvir[6/6775] Virial masssolMassphys.massintTpk[0.7/6.6]? Temperature (only for Table 5)Kphys.temperaturefloatnullableMLTE[33/1482]? LTE mass (only for Table 5)solMassphys.massintnullable