J/A+A/707/A221ivo://CDS.VizieR/J/A+A/707/A221CDSSchisano E.Molinari S.Coletta A.Elia D.Schilke P.Traficante A.,Sanchez-Monge A.Beuther H.Benedettini M.Mininni C.Klessen R.S.,Soler J.D.Nucara A.Pezzuto S.van der Tak F.Hennebelle P.,Beltran M.T.Moscadelli L.Rygl K.L.J.Sanhueza P.Koch P.M.Lis D.C.,Kuiper R.Fuller G.A.Avison A.Bronfman L.Lebreuilly U.Moller T.,Liu T.Pelkonen V.-M.Testi L.Zhang Q.Zhang T.Ahmadi A.Allande J.,Battersby C.Wallace J.Brogan C.L.Clarke S.De Angelis F.Fontani F.,Ho P.T.P.Hunter T.R.Jones B.Johnston K.G.Klaassen P.D.Liu S.J.,Liu S.-Y.Maruccia Y.Rigby A.J.Su Y.-N.Tang Y.Walch S.,Zinnecker H.2026-04-02T06:28:33Z2026-03-24T11:01:11ZCDS support team

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

cds-question@unistra.frinterferometrymillimeter-astronomysubmillimeter-astronomyHigh-mass stars and star clusters form from the fragmentation of massive dense clumps driven by gravity, turbulence and magnetic fields. The extent to which each of these agents impacts the fragmentation depending on the clump mass, density and evolutionary stage is still largely unknown. The ALMAGAL project,with ~1000 clumps observed at ~1000 au resolution, allows a statistically significant characterization of the fragmentation process over a large range of clump physical parameters and evolutionary stages. Our goal is to characterize where and how the dense cores revealed by ALMA are distributed in massive potentially cluster-forming clumps to trace how fragmentation is initially set and how it proceeds before gas dispersal due to stellar feedback. We characterized the spatial distribution of dense cores in the 514 ALMAGAL clumps that host at least 4 cores, using a set of quantitative descriptors that we evaluated against the clump bolometric luminosity-to-mass ratio, which we adopted as an indicator of the evolution of the system. We measured the separations between cores with the minimum spanning tree method (MST), which we compared with the predictions of gravitational fragmentation from Jeans theory. We investigated whether cores have specific arrangements using the Q-parameter or variations due to their masses with the mass segregation ratio, {Lambda}_MSR_. ALMAGAL cores are distributed throughout the entire area of the clump, usually arranged in elliptical groups with an axis ratio e~2.2, although high values with e=>5 are also observed. We found a single characteristic core separation per clump in ~76% of cases, suggesting that multiple fragmentation lengths may be frequently present. Typical core separations are compatible with the clump-averaged thermal Jeans length, lambda^th^_J_. However, we found an additional population of cores, typical of low-fragmented and young clumps, which are on average more widely separated with l =~ 3*{lambda}^th^_J_. By stacking the distributions of the core separations in clumps of similar evolutionary stage, we also found that the separation decreases on average from l~22000 au in younger systems to l~7000 au in more evolved ones. The ALMAGAL cores are typically distributed in fractal-type subclusters, while centrally concentrated patterns appear only at later stages, but we do not observe a progressive transition between these configurations with evolution. Finally, we also found 110 ALMAGAL systems with a signature of mass segregation, with an occurrence that increases with evolution.2026A&A...707A.221Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/707/A221CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/950/148 : ASHES. IX. Massive clumps with ALMA observationsJ/ApJ/886/102 : ALMA obs. of 70um dark high-mass clumps (ASHES)J/ApJ/815/130 : High-mass molecular clumps from MALT90 (Guzman+, 2015)J/ApJ/787/107 : Spatial structure of young stellar clusters. I.J/A+A/696/A149 : ALMAGAL. I. Target clumps properties (Molinari+, 2025)J/A+A/696/A151 : ALMAGAL III. Compact source catalog (Coletta+, 2025)J/A+A/690/A33 : Core mass function in high-mass star formationJ/A+A/682/A81 : CORE Sample NIKA2 and SMA images (Beuther+, 2024)J/A+A/649/A113 : ISOSS22478 and ISOSS23053 images (Beuther+, 2021)J/A+A/648/A66 : CORE high-mass star-forming regions (Gieser+, 2021)J/A+A/645/A94 : NGC 2264 clumps column densities (Nony+, 2021)J/A+A/635/A2 : NGC6334 ALMA 87.6GHz continuum emission mapJ/A+A/615/A9 : Distribution of Serpens South protostars (Plunkett+, 2018)J/A+A/615/A94 : ALMA massive protocluster gas clumps maps (Fontani+, 2018)J/A+A/610/A77 : Orion Integral Filament ALMA+IRAM30m N2H+(1-0) dataJ/A+A/600/A141 : Orion A integral shaped filament image (Kainulainen+, 2017)J/A+A/600/L10 : Massive cluster progenitors from ATLASGAL (Csengeri+, 2017)J/A+A/591/A149 : Hi-GAL. inner Milky Way: +68>=l>=70 (Molinari+, 2016)J/A+A/584/A91 : Catalog of dense cores in Aquila from HerschelJ/ApJ/566/945 : Massive star forming regions at 1.2mm (Beuther+, 2002)J/A+A/561/A83 : SDC13 infrared dark clouds spectra (Peretto+, 2014)J/MNRAS/526/2278 : TEMPO. Fragmentation and emission properties (Avison+, 2023)J/MNRAS/508/2964 : Study of clumps, cores and hubs with ALMA (Anderson+, 2021)J/MNRAS/496/2790 : ATOMS I Description and a first look at G9.62+0.19J/A+A/487/993 : MAMBO Mapping of c2d Clouds and Cores (Kauffmann+, 2008)J/A+A/481/345 : SED evolution in massive young stellar objectsJ/MNRAS/473/849 : Mass segregation in Galactic stellar clusters (Dib+, 2018)J/MNRAS/471/100 : Hi-GAL compact source catalog. -71.0<l<67.0 (Elia+, 2017)J/ApJS/270/9 : ALMA obs. of 11 massive & luminous clumps protoclustersJ/ApJS/208/11 : The Red MSX Source Survey: massive protostarsJ/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/AJ/134/1368 : Proper motions in NGC 2244 and NGC 6530 (Chen+, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/707/A221https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/707/A221http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/707/A221https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/707/A221https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/707/A221http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/707/A221GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/707/A221/table2 (Metrics of ALMAGAL core clusters spatial distrib. as position, sizes and shapes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/707/A221/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/707/A221/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/707/A221/table2?GETtext/xml+votable180.050000true272.25125-20.191420.0055555555555555565/7278 7377 7383 7564 10542 10556 10624 6/20831 22045 29091 29094 29097 29099-29101 29103 29116 29118-29119 29162 29461 29463 29504-29505 29522 29526 29529 30218-30219 30241 30244-30245 30260 30262 30268-30269 37333 37340 37343 37366-37367 37372 37746 37842 37848 37850 37897 37902 37923-37924 37934 38016 38019 38024 39246 39404 39889 41653 41655 41660-41661 41671 41675-41678 41681-41684 41688 41697 41766-41767 41770 41772 41777-41778 41780-41782 41799 41804-41805 41809 41811 41813-41817 41820-41821 41824 42159 42172-42174 42207 42210-42211 42213 42215-42217 42228-42230 42376 42378-42379 42381-42383 42387 42390 42392-42393 42396 42398 42435-42438 42441 42500-42502 42512 43013 43019-43021 43024 43026 43040https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/707/A221?format=asciiMillimeterdefaultJ/A+A/707/A221/table2Metrics of ALMAGAL core clusters spatial distrib. as position, sizes and shapesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameALMAGAL target name (AGLLL.llll+B.bbbb) (Name)meta.id;meta.maincharprimaryT6Link to table6meta.ref.urlcharNcoresNumber of cores (Ncores)meta.numberintRA_ICRSCluster center right ascension (ICRS) (RA_mean_) (1)degpos.eq.ra;meta.mainDE_ICRSCluster center declination (ICRS) (DEC_mean_) (1)degpos.eq.dec;meta.mainOffsetOffset from image center (Offset) (1)arcsecpos;arith.difffloatRadClCluster radius R_cluster_ (RadCl) (2)arcsecphys.angSize;srcfloatRadPhClLinear size of the cluster R^ph^_cluster_ (RadPhCl) (2)pcphys.size.radiusdoubleAreaCHArea of the convex hull (CH) polygon A^CH^ (AreaCH) (3)arcsec**2phys.area;meta.modelled;arithfloatAreaSNormalized CH area to number of cores inside the polygon A^CH^_norm_ (AreaS) (3)arcsec**2phys.area;meta.modelled;arithcharNvCHNumber of vertices of the CH polygon N^hull^_{nu}_ (NvCH) (3)meta.number;meta.modelled;arithintNinCHNumber of cores inside the CH polygon N^hull^_in_ (NinCH) (3)meta.number;meta.modelled;arithintXiRatio of RadCl and R^CH^ equivalent radius (Xi) (4)phys.size.radius;arith.ratiofloatAMajor axis of the fitted ellipse to CH (Axis_A) (4)arcsecphys.angSize.smajAxis;meta.modelledfloatBMinor axis of the fitted ellipse to CH (Axis_B) (4)arcsecphys.angSize.sminAxis;meta.modelledfloatA/B? Axis ratio of the fitted ellipse to CH (Elon) (4)phys.angSize;arith.ratiofloatnullablePA[] Position Angle of the fitted ellipse to CH (PA) (4)degpos.posAng;meta.modelledfloatALMAGALIDisplay ALMAGAL. I. Target clumps properties data from Molinari et al. 2025A&A...696A.149M, Cat. J/A+A/696/A149meta.ref.urlcharALMAGALIIIDisplay ALMAGAL. III. Compact source catalog from Coletta et al. 2025A&A...696A.151C, Cat. J/A+A/696/A151meta.ref.urlcharJ/A+A/707/A221/table3Clump thermal Jeans parameters and reference values of projected l_core_ distributions from MST analysisNameALMAGAL target name (AGLLL.llll+B.bbbb) (Name)meta.id;meta.maincharNcoresNumber of cores (Ncores)meta.numberintMth? Clump-averaged thermal jeans mass (Mth_J) (1)solMassphys.mass;meta.modelled;arithfloatnullableLth? Clump-averaged thermal jeans length (Lth_J) (1)AUphys.size;meta.modelled;arithdoublenullablelminMinimum of projected linear core separations (lmin)AUpos.distance;stat.min;meta.modelleddoublelmaxMaximum of projected linear core separations (lmax)AUpos.distance;stat.max;meta.modelleddoublelmeanMean of projected linear core separations (lmean)AUpos.distance;stat.mean;meta.modelleddoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlstdStandard Deviation of projected linear core separations (lstd)AUpos.distance;stat.stdev;meta.modelleddoublelmedianMedian of projected linear core separations (lmedian)AUpos.distance;stat.median;meta.modelleddoublelq1First Quartile of projected linear core separations (lq1)AUpos.distance;stat.value;meta.modelleddoublelq3Third Quartile of projected linear core separations (lq3)AUpos.distance;stat.value;meta.modelleddoublelmode? Modal of the KDE-derived distribution of projected linear core separations (lmode) (2)AUpos.distance;stat.mean;meta.modelleddoublenullablel1? Inner edge at 68% peak-intensity of the KDE-derived distribution (l1) (2)AUpos.distance;stat.value;meta.modelleddoublenullablel2? Outer edge at 68% peak-intensity of the KDE-derived distribution (l2) (2)AUpos.distance;stat.value;meta.modelleddoublenullableJ/A+A/707/A221/table6Diagnostics of spatial statistics in clumpsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameALMAGAL target name (AGLLL.llll+B.bbbb) (Name)meta.id;meta.maincharNcoresNumber of cores (Ncores)meta.numberintQThe Q parameter (Qpar) (1)phys.size.radius;stat.mean;meta.modelledfloatMeanEdgeMean edge length of cluster MST called m (MeanEdge) (1)phys.size.radius;stat.mean;meta.modelledfloatScorLenCluster correlation length called s (ScorLen) (1)phys.size.radius;stat.mean;meta.modelledfloatNLamCrit? Number of cores at the maximum of the MS ratio profile (NLamCrit) (2)meta.number;meta.modelledintnullableLamPeak? Peak value {Lambda}^max^_MSR_ of the MS ratio profile (LamPeak) (2)pos.distance;arith.ratio;stat.maxfloatnullableNLamPeak? Highest number of cores in MS ratio profile greater than unity (NLamPeak) (2)meta.number;meta.modelledintnullableMSIMass segregation integral I^MSR^_{lambda}_ for MSR profile comparisons of different systems defined by Xu et al. (2024ApJS..270....9X, Cat. J/ApJS/270/9) (MSI)pos.distance;arith.ratio;stat.meanfloatf_MSIMass segregation (MS) flag (MSFlag) (3)meta.codecharProb1? Probability of direct MS in Monte Carlo runs (Prob1) (4)stat.probabilityfloatnullableProb2? Probability of inverse MS in Monte Carlo runs (Prob2) (4)stat.probabilityfloatnullable