J/A+A/709/A264ivo://CDS.VizieR/J/A+A/709/A264CDSGonzalez M.Joncour I.Moraux E.Motte F.Nespoli E.Louvet F.,Valeille-Manet M.Martinez-Badenes V.2026-05-22T09:06:03Z2026-05-22T10:04:38ZCDS support team

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

cds-question@unistra.frstar-forming-regionsgalaxy-classification-systemsvisible-astronomyThe spatial analysis of young stellar objects (YSOs) has proven very valuable to describe and analyse star-forming regions and to understand the star formation process. This work aims to provide a homogeneous catalogue of small, significant substructures (henceforth NESTs) extracted from the spatial distribution of YSOs in a large, consistent sample of star-forming regions. The catalogue allowed us to explore the relevance of small-scale spatial substructure and discuss the interpretation of NESTs as tracers of star formation activity and remnants of the star formation process. We applied our procedure to consistent catalogues of YSOs to obtain NESTs in a sample of star-forming regions. We applied a photometric classification scheme to obtain the evolutionary stage of YSOs and statistically explore the distribution of Class 0/I objects as a proxy of recent star formation activity. The region sample is diverse (in distance, size, structure, and global evolutionary stage), and we consequently found different structural properties and star formation histories. Most NESTs in regions with relevant recent star formation activity showed even higher levels of activity. Moreover, the proportion of NESTs with more activity than the region average increased with the global level of activity of the region. In approximately half of the regions, we also found significant spans in the evolutionary stages of the NESTs, consistently with gradients and episodes of star formation. The combination of NESTs with a statistical exploration of the star formation history within each region provides robust and powerful insights into the star formation process. Our results support the role of NESTs as pristine remnants of star formation in highly active regions, highlighting the role of fragmentation. The combination of small structures with large-scale spatio-evolutionary patterns suggests hierarchical, prolonged, dynamic, and complex star formation scenarios.2026A&A...709A.264Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/709/A264CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/ApJ/787/107 : Spatial structure of young stellar clusters. I. (Kuhn+, 2014)J/MNRAS/477/298 : Young star clusters in nearby molecular cloudshttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/709/A264https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/709/A264http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/709/A264https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/709/A264https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/709/A264http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/709/A264GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/709/A264/tablea1 (General results by region)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/709/A264/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/709/A264/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/709/A264/tablea1?GETtext/xml+votable180.050000true0.56362567.433250.005555555555555556Cone search capability for table J/A+A/709/A264/nests (Characteristics of NESTs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/709/A264/nests?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/709/A264/nests?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/709/A264/nests?GETtext/xml+votable180.050000true0.548477916903967.40242068318650.0055555555555555566/862 1231 1287 1539 3755 3759 13050 14029 14621 14682 14704 15662 15681 15683-15684 21438-21439 21456 21458 22243 22249 22805 22855 22873 22876 23637 28890 28913 29116 29118 29463 29504 29506 30341 30366 37872 37884 38016 39907 42441 42456 42458 42460-42462https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/709/A264?format=asciiOpticaldefaultJ/A+A/709/A264/tablea1General results by regionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionRegion namemeta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainDistDistancepcpos.distanceintNSample size (1)meta.numberintNmergSize after merging (within 2")meta.numberintREquivalent radius convex hullpcphys.size.radiusdoubleQQ structure parameter (Cartwright et al., 2004MNRAS.348..589C)src.morph.paramdoubleNNESTNumber of NESTs in regionmeta.numberintNminMinimum number of points for DBSCANmeta.numberintEpsilonDistance for DBSCANkaupos.distancedoubleRhoRelNominal density of NESTs relative to regionsrc.densitydoublefNESTFraction of stars in NESTsmeta.numberdoubleNMXpopulation of largest NEST relative to Nminmeta.numberfloatJ/A+A/709/A264/tablea2Evolutionary estimates by regionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionRegion namemeta.id;meta.maincharRegimeRecent activity regime (1)meta.codecharNclassNumber of classified objects (2)meta.numberintfclassFraction of classified objectsmeta.numberdoubleDeltafNESTSpan of fraction of Class 0/I in NESTs (3)meta.numberdoublemeanfC0IMean ratio of class 0/I objectsmeta.numberdoubles_meanfC0IDispersion of ratio of class 0/I objectsinstr.dispersion;arith.ratiodoublemeanfCIIMean ratio of class II objectsmeta.numberdoubles_meanfCIIDispersion of ratio of class II objectsinstr.dispersion;arith.ratiodoublemeanfCIIIMean ratio of class III objectsmeta.numberdoubles_meanfCIIIDispersion of ratio of class III objectsinstr.dispersion;arith.ratiodoubleJ/A+A/709/A264/nestsCharacteristics of NESTsIdNestId of NESTmeta.idintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionHost region namemeta.id;meta.maincharRegimeRecent activity (RA) regime region (1)meta.codecharmeanfC0IregionMean ratio of class 0/I in regionmeta.numberdoubles_meanfC0IregionDispersion of ratio of class 0/Iinstr.dispersion;arith.ratiodoubleNstarNumber of stars in NESTmeta.numberintRAJ2000Right ascension (J2000) of NEST centroiddegpos.eq.ra;meta.mainDEJ2000Declination (J2000) of NEST centroiddegpos.eq.dec;meta.mainfC0IEstimated ratio of class 0/I in NESTmeta.numberdoublefCIIEstimated ratio of class II in NESTmeta.numberdoublefCIIIEstimated ratio of class III in NESTmeta.numberdoubles_fC0IUncertainty in fC0Istat.errordoubles_fCIIUncertainty in fCIIstat.errordoubles_fCIIIUncertainty in fCIIIstat.errordouble