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Growing evidence for a core formation threshold traced in Herschel Gould Belt survey clouds
Author(s) -
Könyves V.,
André Ph.,
Schneider N.,
Palmeirim P.,
Arzoumanian D.,
Men'shchikov A.
Publication year - 2013
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.201211956
Subject(s) - protostar , physics , astrophysics , extinction (optical mineralogy) , star formation , molecular cloud , connection (principal bundle) , core (optical fiber) , astronomy , stars , geometry , mathematics , optics
It has already been suggested that a threshold in column density – or in visual extinction – may need to be exceeded to form dense cores and then protostars. Based on Herschel Gould Belt survey results in the Aquila and Orion B molecular cloud complexes we observe clear connection between the locations of the detected prestellar cores and their background column density values. This finding appears to support a core formation scenario where such threshold corresponds to the extinction above which interstellar filaments become gravitationally unstable and fragment into cores. In these two actively star‐forming regions we find the vast majority of the gravitationally bound prestellar cores above a high column density of about (6–7) × 10 21 cm –2 ( AV ∼ 6–7). This limit similarly appears in the column density probability distribution function (PDF) of the regions as well. The spatial distribution of the protostars and young stellar objects (YSOs) also shows a tight connection with the densest sites of both clouds, as more than 70 % of them appear above the mentioned AV thresholds. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)