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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 742638.0, MPI für Astronomie / Publikationen_mpia
Resolving the fragmentation of high line-mass filaments with ALMA: the integral shaped filament in Orion A
Authors:Kainulainen, J.; Stutz, A. M.; Stanke, T.; Abreu-Vicente, J.; Beuther, H.; Henning, T.; Johnston, K. G.; Megeath, S. T.
Date of Publication (YYYY-MM-DD):2017
Title of Journal:Astronomy and Astrophysics
Start Page:id. A141 (15 pp)
Audience:Not Specified
Abstract / Description:We study the fragmentation of the nearest high line-mass filament, the integral shaped filament (ISF, line-mass 400 M pc-1) in the Orion A molecular cloud. We have observed a 1.6 pc long section of the ISF with the Atacama Large Millimetre/submillimeter Array (ALMA) at 3 mm continuum emission, at a resolution of 3″ (1200 AU). We identify from the region 43 dense cores with masses about a solar mass. 60% of the ALMA cores are protostellar and 40% are starless. The nearest neighbour separations of the cores do not show a preferred fragmentation scale; the frequency of short separations increases down to 1200 AU. We apply a two-point correlation analysis on the dense core separations and show that the ALMA cores are significantly grouped at separations below 17 000 AU and strongly grouped below 6000 AU. The protostellar and starless cores are grouped differently: only the starless cores group strongly below 6000 AU. In addition, the spatial distribution of the cores indicates periodic grouping of the cores into groups of 30 000 AU in size, separated by 50 000 AU. The groups coincide with dust column density peaks detected by Herschel. These results show hierarchical, two-mode fragmentation in which the maternal filament periodically fragments into groups of dense cores. Critically, our results indicate that the fragmentation models for lower line-mass filaments ( 16 M pc-1) fail to capture the observed properties of the ISF. We also find that the protostars identified with Spitzer and Herschel in the ISF are grouped at separations below 17 000 AU. In contrast, young stars with disks do not show significant grouping. This suggests that the grouping of dense cores is partially retained over the protostar lifetime, but not over the lifetime of stars with disks. This is in agreement with a scenario where protostars are ejected from the maternal filament by the slingshot mechanism, a model recently proposed for the ISF. The separation distributions of the dense cores and protostars may also provide an evolutionary tracer of filament fragmentation. The reduced continuum image (FITS file) 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=""></A>) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/600/A141">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/600/A141</A>
Free Keywords:ISM: clouds; ISM: structure; stars: formation; ISM: individual objects: OMC-2; radio continuum: ISM
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-6361 %R 10.1051/0004-6361/201628481
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