J/A+A/615/A9ivo://CDS.VizieR/J/A+A/615/A9doi:10.26093/cds/vizier.36150009CDSPlunkett A.L.Fernandez-Lopez M.Arce H.Busquet G.Mardones D.,Dunham M.M2020-09-01T13:13:16Z2018-07-03T08:03:26ZCDS support team

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

cds-question@unistra.frstellar-associationsprotostarsinterferometryClusters are common sites of star formation, whose members display varying degrees of mass segregation. The cause may be primordial or dynamical, or a combination both. If mass segregation were to be observed in a very young protostellar cluster, then the primordial case can be assumed more likely for that region. We investigated the masses and spatial distributions of pre-stellar and protostellar candidates in the young, low-mass star forming region Serpens South, where active star formation is known to occur along a predominant filamentary structure. Previous observations used to study these distributions have been limited by two important observational factors: (1) sensitivity limits that leave the lowest-mass sources undetected, or (2) resolution limits that cannot distinguish binaries and/or cluster members in close proximity. Recent millimeter-wavelength interferometry observations can now uncover faint and/or compact sources in order to study a more complete population of protostars, especially in nearby (D<500pc) clusters. Here we present ALMA observations of 1mm (Band 6) continuum in a 3x2-arcminutes region at the center of Serpens South. Our angular resolution of 1-arcsec is equivalent to 400 au, corresponding to scales of envelopes and/or disks of protostellar sources. We detect 52 sources with 1mm continuum, and we measure masses of 0.002-0.9 solar masses corresponding to gas and dust in the disk and/or envelope of the protostellar system. For the deeply embedded (youngest) sources with no IR counterparts, we find evidence of mass segregation and clustering according to: the Minimum Spanning Tree method, distribution of projected separations between unique sources, and concentration of higher-mass sources near to the dense gas at the cluster center. The mass segregation of the mm sources is likely primordial rather than dynamical given the young age of this cluster, compared with segregation time. This is the first case to show this for mm sources in a low-mass protostellar cluster environment.2018A&A...615A...9Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/615/A9CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/615/A9https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/615/A9http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/615/A9https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/615/A9https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/615/A9http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/615/A9GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/615/A9/tablea1 (Sources in mapped region)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/615/A9/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/615/A9/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/615/A9/tablea1?GETtext/xml+votable180.050000true277.493004167-2.0225002780.005555555555555556Cone search capability for table J/A+A/615/A9/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/615/A9/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/615/A9/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/615/A9/list?GETtext/xml+votable180.050000true277.51247-2.041690.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/615/A96/303411.528037907652962e-22 1.528037907652962e-22https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/615/A9?format=asciidefaultJ/A+A/615/A9/tablea1Sources in mapped regionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName (SerpsNN)meta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainClassClassificationsrc.classcharalpha? Radio spectral indexspect.indexfloatnullableFWHMmaj? FWHM of major axis (1)arcsecphys.angSizefloatnullablen_FWHMmaj[ui] Note on FWHMmaj (2)meta.notecharFWHMmin? FWHM of minor axis (1)arcsecphys.angSizefloatnullablen_FWHMmin[u] Note on FWHMmin (2)meta.notecharPA[]? Position angle (1)degpos.posAngfloatnullablen_PA[u] Note on PA (2)meta.notecharFPeak? Peak flux at 1.3mmmJy/beamphot.flux.density;em.mm.200-400GHzfloatnullableFlux? Flux density at 1.3mmmJyphot.flux.density;em.mm.200-400GHzfloatnullableMass? MasssolMassphys.massfloatnullableD15Source ID for matching source in Dunham et al. (2015, Cat. J/ApJS/220/11) catalogmeta.idcharn_D15[d] Note on D15 (3)meta.notecharX[X-] X indicates an X-ray source counterpart (Getman et al., 2017, Cat. J/ApJS/229/28)meta.codecharn_X[g] Note on X (4)meta.notecharR? Specific radio source counterpart labeled as VLANN by Kern et al. (2016AJ....151...42K)meta.idintnullablen_R[efgh] Note on R (4)meta.notecharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/615/A9/listList of fits imagesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.DateObservation date (2014-03-22T08:59:09.84)time.epoch;obscharFreqObserved frequencyGHzem.freqfloatsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar