ALMA survey of massive cluster progenitors from ATLASGAL. Limited fragmentation at the early evolutionary stage of massive clumps

Csengeri, T.T.CsengeriBontemps, S.S.BontempsWyrowski, F.F.WyrowskiMotte, F.F.MotteMenten, K. M.K. M.MentenBeuther, H.H.BeutherBronfman, L.L.BronfmanCommerçon, B.B.CommerçonChapillon, E.E.ChapillonDuarte-Cabral, A.A.Duarte-CabralFuller, G. A.G. A.FullerHenning, Th.Th.HenningLeurini, SilviaSilviaLeuriniLongmore, S.S.LongmorePalau, A.A.PalauPeretto, N.N.PerettoSchuller, F.F.SchullerTan, J. C.J. C.TanTesti, L.L.TestiTRAFICANTE, ALESSIOALESSIOTRAFICANTEUrquhart, J. S.J. S.Urquhart2020-07-222020-07-2220170004-6361http://hdl.handle.net/20.500.12386/26555The early evolution of massive cluster progenitors is poorly understood. We investigate the fragmentation properties from 0.3 pc to 0.06 pc scales of a homogenous sample of infrared-quiet massive clumps within 4.5 kpc selected from the ATLASGAL survey. Using the ALMA 7 m array we detect compact dust continuum emission towards all targets and find that fragmentation, at these scales, is limited. The mass distribution of the fragments uncovers a large fraction of cores above 40 M☉, corresponding to massive dense cores (MDCs) with masses up to 400 M☉. Seventy-seven percent of the clumps contain at most 3 MDCs per clump, and we also reveal single clumps/MDCs. The most massive cores are formed within the more massive clumps and a high concentration of mass on small scales reveals a high core formation efficiency. The mass of MDCs highly exceeds the local thermal Jeans mass, and we lack the observational evidence of a sufficiently high level of turbulence or strong enough magnetic fields to keep the most massive MDCs in equilibrium. If already collapsing, the observed fragmentation properties with a high core formation efficiency are consistent with the collapse setting in at parsec scales. Full Table A.1 is only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/600/L10">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/600/L10</A>STAMPAenALMA survey of massive cluster progenitors from ATLASGAL. Limited fragmentation at the early evolutionary stage of massive clumpsArticle10.1051/0004-6361/2016297542-s2.0-85017176513000400754000084https://www.aanda.org/articles/aa/abs/2017/04/aa29754-16/aa29754-16.html2017A&A...600L..10CFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_6 Stars and stellar systems