J/A+A/687/A163ivo://CDS.VizieR/J/A+A/687/A163doi:10.26093/cds/vizier/bc-nf/lbgdCDSBonfand M.Csengeri T.Bontemps S.Brouillet N.Motte F.Louvet F.,Ginsburg A.Cunningham N.Galvan-Madrid R.Herpin F.Wyrowski F.,Valeille-manet M.Stutz A.M.Di Francesco J.Gusdorf A.,Fernandez-lopez M.Lefloch B.Liu H.-L.Sanhueza P.,Alvarez-Gutierrez R.H.Olguin F.Nony T.Lopez-Sepulcre A.Dell'Ova P.,Pouteau Y.Jeff D.Chen H.-R.V.Armante M.Towner A.Bronfman L.,Kessler N.2026-07-03T06:36:04Z2025-03-20T14:24:56ZCDS support team

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

cds-question@unistra.frstar-forming-regionsinfrared-sourcesinterstellar-mediumgalaxy-classification-systemsThe star formation process leads to an increased chemical complexity in the interstellar medium. Sites associated with highmass star and cluster formation exhibit a so-called hot core phase, characterized by high temperatures and column densities of complex organic molecules. We aim to systematically search for and identify a sample of hot cores toward the 15 Galactic protoclusters of the ALMA-IMF Large Program and investigate their statistical properties. We built a comprehensive census of hot core candidates toward the ALMA-IMF protoclusters based on the detection of two CH_3_OCHO emission lines at 216.1GHz. We used the source extraction algorithm GExt2D to identify peaks of methyl formate (CH_3_OCHO) emission, a complex species commonly observed toward sites of star formation.We performed a cross-matching with the catalog of thermal dust continuum sources from the ALMA-IMF 1.3mm continuum data to infer their physical properties. We built a catalog of 76 hot core candidates with masses ranging from ~0.2M_{sun}_ to ~80M_{sun}_, of which 56 are new detections. A large majority of these objects, identified from methyl formate emission, are compact and rather circular, with deconvolved full width at half maximum (FWHM) sizes of ~2300 au on average. The central sources of two target fields show more extended, but still rather circular, methyl formate emission with deconvolved FWHM sizes of ~6700au and 13400au. About 30% of our sample of methyl formate sources have core masses above 8M_{sun}_ and range in size from ~1000au to 13400au, which is in line with measurements of archetypical hot cores. The origin of the CH_3_OCHO emission toward the lower-mass cores may be explained as a mixture of contributions from shocks or may correspond to objects in a more evolved state (i.e., beyond the hot core stage). We find that the fraction of hot core candidates increases with the core mass, suggesting that the brightest dust cores are all in the hot core phase. Our results suggest that most of these compact methyl formate sources are readily explained by simple symmetric models, while collective effects from radiative heating and shocks from compact protoclusters are needed to explain the observed extended CH_3_OCHO emission. The large fraction of hot core candidates toward the most massive cores suggests that they rapidly enter the hot core phase and that feedback effects from the forming protostar(s) impact their environment on short timescales.2024A&A...687A.163Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/687/A163CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/662/A9 : 15 dense molecular cloud regions ALMA images (Ginsburg+, 2022)J/A+A/664/A26 : W43-MM2+MM3 ministarburst ALMA data (Pouteau+, 2022)J/A+A/674/A75 : W43-MM1 and W43-MM2+MM3 ALMA datacubes (Nony+, 2023)J/A+A/687/A217 : 15 massive protoclusters point-process mappingJ/A+A/690/A33 : Core mass function in high-mass star formation (Louvet+, 2024)J/A+A/694/A24 : ALMA-IMF XVI (Motte+, 2025)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/687/A163https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/687/A163http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/687/A163https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/687/A163https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/687/A163http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/687/A163GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/687/A163/table4 (Catalog of the sources extracted from the moment 0 maps of methyl formate using the GExt2D algorithm)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/687/A163/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/687/A163/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/687/A163/table4?GETtext/xml+votable180.050000true271.5792083-21.62555560.005555555555555556Cone search capability for table J/A+A/687/A163/tablec1 (Properties of the continuum cores associated with the methyl formate sources toward the 15 ALMA-IMF protoclusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/687/A163/tablec1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/687/A163/tablec1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/687/A163/tablec1?GETtext/xml+votable180.050000true271.57925-21.62561110.0055555555555555566/28919 29091 29101 30262 30694 41812 42172 42224 42230 42451 42455 424966.621485433431823e-23 1.528037907652962e-22https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/687/A163?format=asciiOpticalInfrareddefaultJ/A+A/687/A163/table4Catalog of the sources extracted from the moment 0 maps of methyl formate using the GExt2D algorithmrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster namemeta.id.parentcharID? Source Id within the clustermeta.idintnullableNameName of the sourcemeta.id;meta.maincharOName? Previously identified toward W43-MM1 in Paper IV (Brouillet et al., 2022A&A...665A.140B) Id numbermeta.idintnullablen_Name[*] Note (1)meta.notecharRAJ2000Peak right ascension (J2000) (2)pos.eq.ra;meta.mainDEJ2000Peak declination (J2000) (2)pos.eq.dec;meta.mainSpeakMF? Peak intensity (2)mJy.beam**-1.km.s**-1phot.flux.density;em.radiofloatnullableS/N? Signal-to-noise ratio (2)stat.snrfloatnullablethetamaj? Major axis (2)arcsecphys.angSizefloatnullablethetamin? Minor axis (2)arcsecphys.angSize;srcfloatnullablePA[]? Position angle (2)degpos.posAngfloatnullablethetamajd? Deconvolved major axis (3)arcsecphys.angSizefloatnullablethetamind? Deconvolved minor axis (3)arcsecphys.angSize;srcfloatnullablePAd[]? Deconvolved position angledegpos.posAngfloatnullableFWHMMFd? Mean deconvolved FWHM source size of the methyl formate emission is computed at the distance of each protocluster (4)auphys.size;stat.meanfloatnullableVLSR? Rest velocity of the source (5)km/sphys.veloc;pos.lsrfloatnullablee_VLSR? Rest velocity of the source errorkm/sstat.error;phys.veloc;pos.lsrfloatnullableChannels? Percentage of the total number of channels per spw that contain emission above the 3{sigma} noise level (Sect. 3.3)%meta.numberintnullableClassTentative classification (6)src.classcharJ/A+A/687/A163/tablec1Properties of the continuum cores associated with the methyl formate sources toward the 15 ALMA-IMF protoclustersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000? Right ascension (J2000) (2)pos.eq.ra;meta.mainnullableDEJ2000? Declination (J2000) (2)pos.eq.dec;meta.mainnullabled? Angular offset between the peak position of the methyl formate source and its associated compact continuum corearcsecmeta.id.assoc;pos.angDistance;spect.continuumfloatnullableS1.3mmpkPeak intensity at 1.3mm from the unsmoothed core catalog (Dell'Ova et al., 2024, Cat. J/A+A/687/A217) (3)mJy/beamphot.flux.density;em.mm.200-400GHzfloate_S1.3mmpkPeak intensity at 1.3mm from the unsmoothed core catalog errormJy/beamstat.errorfloatS1.3mmintIntegrated intensity at 1.3mm from the unsmoothed core catalog (Dell'Ova et al., 2024, Cat. J/A+A/687/A217)mJyphot.flux.density;em.mm.200-400GHzfloate_S1.3mmintIntegrated intensity at 1.3mm from the unsmoothed core catalog errormJystat.errorfloatthetamaj? Major axis of the compact continuum core from the unsmoothed core catalog (Dell'Ova et al., 2024, Cat. J/A+A/687/A217) (4)arcsecphys.angSizefloatnullablethetamin? Minor axis of the compact continuum core from the unsmoothed core catalog (Dell'Ova et al., 2024, Cat. J/A+A/687/A217) (4)arcsecphys.angSize;srcfloatnullablePA[]? Position angle of the compact continuum core from the unsmoothed core catalog (Dell'Ova et al., 2024, Cat. J/A+A/687/A217) (4)degpos.posAng;spect.continuumfloatnullableFWHMMFdDeconvolved mean size (FWHM) of the continuum coresauphys.angSize;stat.meanfloatS3mmint3mm integrated intensity from the unsmoothed core catalog (Dell'Ova et al., 2024, Cat. J/A+A/687/A217)mJyphot.flux.density;em.mm.50-100GHzfloate_S3mmint3mm integrated intensity from the unsmoothed core catalog (XII) errormJystat.errorfloattau? Opacity computed at Td=100K (5)phys.absorption.coefffloatnullableMass1? Mass range, lower value (6)solMassphys.mass;stat.minfloatnullableMass2? Mass range, upper value (6)solMassphys.mass;stat.maxfloatnullableMcore? Core mass used to plot Figs. 13, 16 and 18, computed at Td=100K for all methyl formate sources (5)solMassphys.mass;instr.setupfloatnullablealphaSpectral index (see Sect. 5.2)spect.indexfloatfracffFraction of the fluxes measured at 1.3mm that is due to free-free emission and that are subtracted to the fluxes given in S1.3mmpeak and S1.3mmint to obtain the mass estimates given in Mass1-Mass2 and Mcore%phot.flux;arith.ratiointClusterCluster name (1)meta.id.parentcharNameID of the methyl formate sourcesmeta.id;meta.maincharn_Name[*] Note on Name (1)meta.notechar