scholarly journals Dust polarized emission observations of NGC 6334. BISTRO reveals the details of the complex but organized magnetic field structure of the high-mass star-forming hub-filament network

Author(s):  
D. Arzoumanian ◽  
R. Furuya ◽  
T. Hasegawa ◽  
M. Tahani ◽  
S. Sadavoy ◽  
...  
2021 ◽  
Vol 923 (2) ◽  
pp. 204
Author(s):  
Paulo C. Cortés ◽  
Patricio Sanhueza ◽  
Martin Houde ◽  
Sergio Martín ◽  
Charles L. H. Hull ◽  
...  

Abstract Here, we report ALMA detections of polarized emission from dust, CS(J = 5 → 4), and C33S(J = 5 → 4) toward the high-mass star-forming region NGC 6334I(N). A clear “hourglass” magnetic field morphology was inferred from the polarized dust emission, which is also directly seen from the polarized CS emission across velocity, where the polarization appears to be parallel to the field. By considering previous findings, the field retains a pinched shape that can be traced to clump length scales from the envelope scales traced by ALMA, suggesting that the field is dynamically important across multiple length scales in this region. The CS total intensity emission is found to be optically thick (τ CS = 32 ± 12) while the C33S emission appears to be optically thin ( τ C 33 S = 0.1 ± 0.01 ). This suggests that sources of anisotropy other than large velocity gradients, i.e., anisotropies in the radiation field, are required to explain the polarized emission from CS seen by ALMA. By using four variants of the Davis–Chandrasekhar–Fermi technique and the angle dispersion function methods (ADF), we obtain an average of the estimates for the magnetic field strength on the plane of the sky of B pos = 16 mG from the dust and B pos ∼ 2 mG from the CS emission, where each emission traces different molecular hydrogen number densities. This effectively enables a tomographic view of the magnetic field within a single ALMA observation.


1984 ◽  
pp. 333-334
Author(s):  
J. A. Garcia-Barreto ◽  
B. F. Burke ◽  
M. J. Reid ◽  
J. M. Moran ◽  
A. D. Haschick

1988 ◽  
Vol 326 ◽  
pp. 954 ◽  
Author(s):  
J. A. Garcia-Barreto ◽  
B. F. Burke ◽  
M. J. Reid ◽  
J. M. Moran ◽  
A. D. Haschick ◽  
...  

2019 ◽  
Vol 630 ◽  
pp. A54 ◽  
Author(s):  
M. T. Beltrán ◽  
M. Padovani ◽  
J. M. Girart ◽  
D. Galli ◽  
R. Cesaroni ◽  
...  

Context. Submillimeter Array (SMA) 870 μm polarization observations of the hot molecular core G31.41+0.31 revealed one of the clearest examples up to date of an hourglass-shaped magnetic field morphology in a high-mass star-forming region. Aims. To better establish the role that the magnetic field plays in the collapse of G31.41+0.31, we carried out Atacama Large Millimeter/ submillimeter Array (ALMA) observations of the polarized dust continuum emission at 1.3 mm with an angular resolution four times higher than that of the previous (sub)millimeter observations to achieve an unprecedented image of the magnetic field morphology. Methods. We used ALMA to perform full polarization observations at 233 GHz (Band 6). The resulting synthesized beam is 0′′.28×0′′.20 which, at the distance of the source, corresponds to a spatial resolution of ~875 au. Results. The observations resolve the structure of the magnetic field in G31.41+0.31 and allow us to study the field in detail. The polarized emission in the Main core of G31.41+0.41is successfully fit with a semi-analytical magnetostatic model of a toroid supported by magnetic fields. The best fit model suggests that the magnetic field is well represented by a poloidal field with a possible contribution of a toroidal component of ~10% of the poloidal component, oriented southeast to northwest at approximately −44° and with an inclination of approximately −45°. The magnetic field is oriented perpendicular to the northeast to southwest velocity gradient detected in this core on scales from 103 to 104 au. This supports the hypothesis that the velocity gradient is due to rotation of the core and suggests that such a rotation has little effect on the magnetic field. The strength of the magnetic field estimated in the central region of the core with the Davis–Chandrasekhar-Fermi method is ~8–13 mG and implies that the mass-to-flux ratio in this region is slightly supercritical. Conclusions. The magnetic field in G31.41+0.31 maintains an hourglass-shaped morphology down to scales of <1000 au. Despite the magnetic field being important in G31.41+0.31, it is not enough to prevent fragmentation and collapse of the core, as demonstrated by the presence of at least four sources embedded in the center of the core.


2010 ◽  
Vol 724 (1) ◽  
pp. L113-L117 ◽  
Author(s):  
H. Beuther ◽  
W. H. T. Vlemmings ◽  
R. Rao ◽  
F. F. S. van der Tak

2018 ◽  
Vol 614 ◽  
pp. A64 ◽  
Author(s):  
H. Beuther ◽  
J. D. Soler ◽  
W. Vlemmings ◽  
H. Linz ◽  
Th. Henning ◽  
...  

Context. The importance of magnetic fields at the onset of star formation related to the early fragmentation and collapse processes is largely unexplored today. Aims. We want to understand the magnetic field properties at the earliest evolutionary stages of high-mass star formation. Methods. The Atacama Large Millimeter Array is used at 1.3 mm wavelength in full polarization mode to study the polarized emission, and, using this, the magnetic field morphologies and strengths of the high-mass starless region IRDC 18310-4. Results. Polarized emission is clearly detected in four sub-cores of the region; in general it shows a smooth distribution, also along elongated cores. Estimating the magnetic field strength via the Davis-Chandrasekhar-Fermi method and following a structure function analysis, we find comparably large magnetic field strengths between ~0.3–5.3 mG. Comparing the data to spectral line observations, the turbulent-to-magnetic energy ratio is low, indicating that turbulence does not significantly contribute to the stability of the gas clump. A mass-to-flux ratio around the critical value 1.0 – depending on column density – indicates that the region starts to collapse, which is consistent with the previous spectral line analysis of the region. Conclusions. While this high-mass region is collapsing and thus at the verge of star formation, the high magnetic field values and the smooth spatial structure indicate that the magnetic field is important for the fragmentation and collapse process. This single case study can only be the starting point for larger sample studies of magnetic fields at the onset of star formation.


2016 ◽  
Author(s):  
Gabriele Surcis ◽  
Wouter H.T. Vlemmings ◽  
Huib Jan van Langevelde ◽  
Busaba Hutawarakorn Kramer

2015 ◽  
Vol 75-76 ◽  
pp. 269-272 ◽  
Author(s):  
Á. Sánchez-Monge ◽  
P. Schilke ◽  
A. Zernickel ◽  
A. Schmiedeke ◽  
Th. Möller ◽  
...  

2012 ◽  
Vol 759 (1) ◽  
pp. 25 ◽  
Author(s):  
S. A. Mao ◽  
N. M. McClure-Griffiths ◽  
B. M. Gaensler ◽  
M. Haverkorn ◽  
R. Beck ◽  
...  

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