Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Evolution of the Hub-filament Structures in IC 5146 in the Context of the Energy Balance of Gravity, Turbulence, and Magnetic Field
Ist Teil von
The Astronomical journal, 2022-11, Vol.164 (5), p.175
Ort / Verlag
Madison: The American Astronomical Society
Erscheinungsjahr
2022
Quelle
EZB Electronic Journals Library
Beschreibungen/Notizen
Abstract
We present the results of 850
μ
m polarization and C
18
O (3 − 2) line observations toward the western hub-filament structure (W-HFS) of the dark Streamer in IC 5146 using the James Clerk Maxwell Telescope SCUBA-2/POL-2 and HARP instruments. We aim to investigate how the relative importance of the magnetic field, gravity, and turbulence affects core formation in HFS by comparing the energy budget of this region. We identified four 850
μ
m cores and estimated the magnetic field strengths (
B
pos
) of the cores and the hub and filament using the Davis–Chandrasekhar–Fermi method. The estimated
B
pos
is ∼80 to 1200
μ
G. From Wang et al.,
B
pos
of E-47, a core in the eastern hub (E-hub), and E-hub were reestimated to be 500 and 320
μ
G, respectively, with the same method. We measured the gravitational (
E
G
), kinematic (
E
K
), and magnetic energies (
E
B
) in the filament and hubs and compared the relative importance among them. We found that an
E
B
-dominant filament has
aligned
fragmentation type, while
E
G
-dominant hubs show
no
and
clustered
fragmentation types. In the
E
G
dominant hubs, it seems that the portion of
E
K
determines whether the hub becomes to have
clustered
(the portion of
E
K
∼ 20%) or
no
fragmentation type (∼10%). We propose an evolutionary scenario for the E- and W-HFSs, where the HFS forms first by the collision of turbulent flows, and then the hubs and filaments can go into various types of fragmentation depending on their energy balance of gravity, turbulence, and magnetic field.