J/MNRAS/503/4601ivo://CDS.VizieR/J/MNRAS/503/4601doi:10.26093/cds/vizier.75034601CDSBarnes A.T.Henshaw J.D.Fontani F.Pineda J.E.Cosentino G.Tan J.C.,Caselli P.Jimenez-serra I.Law C.Y.Avison A.Bigiel F.Feng S.,Kong S.Longmore S.N.Moser L.Parker R.J.Sanchez-monge A.Wang K.2024-11-06T20:33:28Z2024-04-26T12:36:30ZCDS support team

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

cds-question@unistra.frinfrared-sourcesmillimeter-astronomysubmillimeter-astronomymolecular-cloudsphotometrystar-forming-regionsmilky-way-galaxyInfrared dark clouds (IRDCs) are potential hosts of the elusive early phases of high mass star formation (HMSF). Here, we conduct an in-depth analysis of the fragmentation properties of a sample of 10 IRDCs, which have been highlighted as some of the best candidates to study HMSF within the Milky Way. To do so, we have obtained a set of large mosaics covering these IRDCs with Atacama Large Millimeter/submillimeter Array (ALMA) at Band 3 (or 3 mm). These observations have a high angular resolution (~3 arcsec; ~0.05 pc), and high continuum and spectral line sensitivity (~0.15 mJy/beam and ~0.2 K per 0.1 km/s^ channel at the N_2_H^+^ (1 - 0) transition). From the dust continuum emission, we identify 96 cores ranging from low to high mass (M = 3.4-50.9 M_{sun}_) that are gravitationally bound ({alpha}_vir_ = 0.3-1.3) and which would require magnetic field strengths of B = 0.3-1.0 mG to be in virial equilibrium. We combine these results with a homogenized catalogue of literature cores to recover the hierarchical structure within these clouds over four orders of magnitude in spatial scale (0.01-10 pc). Using supplementary observations at an even higher angular resolution, we find that the smallest fragments (<0.02 pc) within this hierarchy do not currently have the mass and-or the density required to form high-mass stars. None the less, the new ALMA observations presented in this paper have facilitated the identification of 19 (6 quiescent and 13 star-forming) cores that retain > 16 M_{sun}_ without further fragmentation. These high-mass cores contain trans-sonic non-thermal motions, are kinematically sub-virial, and require moderate magnetic field strengths for support against collapse. The identification of these potential sites of HMSF represents a key step in allowing us to test the predictions from high-mass star and cluster formation theories.2021MNRAS.503.4601Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/503/4601CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/503/4601https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/503/4601http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/503/4601https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/503/4601https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/503/4601http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/503/4601GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/503/4601/tablea12 (Observational properties of the core population)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/503/4601/tablea12?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/503/4601/tablea12?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/503/4601/tablea12?GETtext/xml+votable180.050000true276.5641621320392-12.69367389824620.005555555555555556Cone search capability for table J/MNRAS/503/4601/tablea3 (Properties of the homogenized literature core sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/503/4601/tablea3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/503/4601/tablea3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/503/4601/tablea3?GETtext/xml+votable180.050000true274.46-15.89388888888890.0055555555555555566/29118 29508 29510 29529 29532-29533 29535 30218 30245 30256 30258 30262-30263 30312 30315 30318-30319 30330 30417 30421 30692 307162.837779945223663e-21 2.837779945223663e-21https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/503/4601?format=asciiInfraredMillimeterdefaultJ/MNRAS/503/4601/tablea12Observational properties of the core populationMext? The extinction mass (Mext) (4)solMassphys.absorptiondoublenullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDCore cloud ID (ID)meta.idintMachvrsub? The residual sonic substracted Mach number (Mach_velressub)phys.veloc;arith.diffdoublenullableMachs? The sonic non thermal Mach number (Machs_nonthermal)phys.veloc;arith.diffdoublenullableCloudHost infrared dark cloud name, cloudN, [BT2009] N in Simbad (Cloud)meta.id.parentcharRAJ2000Right ascension of the core center (J2000) (RA_cen)degpos.eq.ra;meta.mainDEJ2000Declination of the core center (J2000) (Dec_cen)degpos.eq.dec;meta.mainReffEffective radius (radius_eff)arcsecphys.angSizedoubleAreaExactExact area defined by {pi}*Reff^2^ (AreaExact)arcsec**2phys.areadoubleAreaEllipseCore cloud ellipse area computed from major_sigma, minor_sigma and position_angle (AreaEllipse)arcsec**2phys.area;meta.modelleddoublemajorSigmaparameter linked to semi-major axis of the Ellipse area parameter AreaEllipse (majorSigma)arcsecphys.angSize;srcdoubleminorSigmaParameter linked to the semi-minor axis of the Ellipse area parameter AreaEllipse (minorSigma)arcsecphys.angSize;srcdoublePA[] Position angle defining the Core cloud ellipse inclination (PositionAngle)degpos.posAngdoubleSvThe total continuum flux density (Sv)Jyphot.flux.density;em.mm.50-100GHzdoubleSvbThe background-subtracted flux density (Svb)Jyphot.flux.density;em.mm.50-100GHzdoubleIvmaxThe peak continuum intensity from Sv (Ivmax)Jyphot.flux.density;em.mm.50-100GHzdoubleTmaxTemperature (Tmax) (1)Kphys.temperaturedoublev0Centroid velocity (v0) (1)km/sphys.velocdoublee_v0velocity dispersion (sigmav) (1)km/sstat.errordoubleMMcoreMillimetre core region label (MM) (2)meta.id;obs.fieldcharf_SF[0/1] Binary number 0 or 1 (SF) (3)meta.codeintSF[y/n] Yes or No (SF)meta.codecharDistanceCore cloud distance in parsec units (Distance_parsec)pcpos.distancefloatReffpcEffective radius in untis of parsecs (Reff)pcphys.size.radiusdoubleSminThe minimum separation or nearest neighbour distance (Smin)pcpos.distancedoubleTdustThe mean dust temperature (Tdust)Kphys.temperaturedoubleMThe mass determined using the mean dust temperature (M)solMassphys.mass;stat.meandoubleMbThe background-subtracted mass using the mean dust temperature (Mb)solMassphys.mass;stat.meandoubleM18KThe mass determined using a constant temperature of 18K (M18K)solMassphys.massdoubleMb18KThe background-subtracted mass using a constant temperature of 18K (Mb18K)solMassphys.massdoubleS70um? The flux density at 70um (S70um) (5)uJyphot.flux.density;em.IR.30-60umdoublenullableCoreCore cloud name, ANcNN (Name)meta.id;meta.maincharT70um? Estimated temperature associated to S70um flux density (T70um)Kphys.temperaturedoublenullableM70um? The mass estimates using a temperature determined from 70 um emission (M70um)solMassphys.massdoublenullablenH2The mean density of H2 into the core cloud (nH2)cm**-3phys.densitydoublenH2bgsubThe background-subtracted mean density (nH2_bgsub)cm**-3phys.densitydoubletffthe free-fall time (tff)Myrtime.epochdoubletffbgsubThe background-subtracted free-fall time (tff_bgsub)Myrtime.epochdoublealphavirThe virial parameter ({alpha}vir)phys.mass;arith.ratiodoublealphavirbThe background-subtracted virial paramete (alphavirb)phys.mass;arith.ratiodoublesigmavrsubThe residual velocity substracted (sigmavelressub)km/sstat.fit.residual;phys.velocdoublesigmaNT? The non-thermal velocity dispersion (sigmaNT)km/sphys.veloc.dispersiondoublenullableJ/MNRAS/503/4601/tablea3Properties of the homogenized literature core samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCloudHost cloud name, cloudN, [BT2009] N in Simbad (cloud)meta.id.parentcharCloudIDHost cloud ID, GLLL.ll+BB.bb, MSXDC GLLL.ll+BB.bb, in Simbad) (cloudID)meta.idcharCoreCore cloud name, ANcNN (Name)meta.id;meta.maincharRAJ2000Core cloud right ascension (J2000) (RAdeg)degpos.eq.ra;meta.mainRefLiterature reference (ref) (1)meta.ref;pos.framecharDEJ2000Core cloud declination (J2000) (DEdeg)degpos.eq.dec;meta.mainReffEffective radius in arsec unit (Reff)arcsecphys.angSizedoubleReffpcEffective radius in parsec unit (Reffpc)pcphys.size.radiusdoubleSlambdaThe total flux density at the observed frequency (Slambda)Jyphot.flux.density;em.radiodoubleM18KThe mass assuming a constant temperature of 18 K (M18K)solMassphys.massdoublelambdathe wavelength of the observations (lambda)mmem.wl;obsfloat