Query : 2016A&A...594A..58O

2016A&A...594A..58O - Astronomy and Astrophysics, volume 594A, 58-58 (2016/10-1)

The segregation of starless and protostellar clumps in the Hi-GAL l = 224° region.


Abstract (from CDS):

Context. Stars form in dense, dusty structures, which are embedded in larger clumps of molecular clouds often showing a clear filamentary structure on large scales (≥1pc). The origin (e.g., turbulence or gravitational instabilities) and evolution of these filaments, as well as their relation to clump and core formation, are not yet fully understood. A large sample of both starless and protostellar clumps can now be found in the Herschel Infrared GALactic Plane Survey (Hi-GAL) key project, which also provides striking images of the filamentary structure of the parent molecular clouds. Recent results indicate that populations of clumps on and off filaments may differ.
Aims. One of the best-studied regions in the Hi-GAL survey can be observed toward the l=224° field. Here, a filamentary region has been studied and it has been found that protostellar clumps are mostly located along the main filament, whereas starless clumps are detected off this filament and are instead found on secondary, less prominent filaments. We want to investigate this segregation effect and how it may affect the clumps properties.
Methods. We mapped the 12CO (1-0) line and its main three isotopologues toward the two most prominent filaments observed toward the l=224° field using the Mopra radio telescope, in order to set observational constraints on the dynamics of these structures and the associated starless and protostellar clumps.
Results. Compared to the starless clumps, the protostellar clumps are more luminous, more turbulent and lie in regions where the filamentary ambient gas shows larger linewidths. We see evidence of gas flowing along the main filament, but we do not find any signs of accretion flow from the filament onto the Hi-GAL clumps. We analyze the radial column density profile of the filaments and their gravitational stability.
Conclusions. The more massive and highly fragmented main filament appears to be thermally supercritical and gravitationally bound, assuming that all of the non-thermal motion is contributing thermal-like support, suggesting a later stage of evolution compared to the secondary filament. The status and evolutionary phase of the Hi-GAL clumps would then appear to correlate with that of the host filament.

Abstract Copyright: © ESO, 2016

Journal keyword(s): stars: formation - ISM: clouds - ISM: molecules

VizieR on-line data: <Available at CDS (J/A+A/594/A58): list.dat fits/*>

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 * alf UMi cC* 02 31 49.09456 +89 15 50.7923 3.00 2.62 2.02 1.53 1.22 F8Ib 667 2
2 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1620 0
3 LDN 1641 MoC 05 39.0 -07 00           ~ 475 0
4 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 1077 2
5 NAME Serpens South Cluster Cl* 18 30 03.00 -02 01 58.2           ~ 129 0
6 NAME Aql Region reg 18 31.1 -02 10           ~ 378 0
7 DR 21 SFR 20 39 01.6 +42 19 38           O4.5 1036 0
8 IC 5146 OpC 21 53 29.3 +47 14 46           ~ 455 2

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