J/A+A/631/A154 IRAS 15398-3359 polarization maps (Redaelli+, 2019)
Magnetic properties of the protostellar core IRAS 15398-3359.
Redaelli E., Alves F.O., Santos F.P., Caselli P.
<Astron. Astrophys. 631, A154 (2019)>
=2019A&A...631A.154R 2019A&A...631A.154R (SIMBAD/NED BibCode)
ADC_Keywords: Infrared sources ; Magnetic fields ; Polarization
Keywords: ISM: clouds - ISM: magnetic fields - stars: protostars -
stars: formation - techniques: polarimetric -
ISM: individual objects: IRAS 15398-3359
Abstract:
Magnetic fields can significantly affect the star formation process.
The theory of the magnetically driven collapse in a uniform field
predicts that the contraction initially happens along the field lines.
When the gravitational pull grows strong enough, the magnetic field
lines pinch inwards, giving rise to a characteristic hourglass shape.
We investigate the magnetic field structure of a young Class 0 object,
IRAS 15398-3359, embedded in the Lupus I cloud. Previous observations
at large scales have suggested that this source evolved in an highly
magnetised environment. This object thus appears to be an ideal
candidate to study the magnetically driven core collapse in the
low-mass regime.
We performed polarisation observations of IRAS 15398-3359 at 214um
using the SOFIA telescope, thus tracing the linearly polarised thermal
emission of cold dust.
Our data unveil a significant bend of the magnetic field lines from
the gravitational pull. The magnetic field appears ordered and aligned
with the large-scale B-field of the cloud and with the outflow
direction. We estimate a magnetic field strength of B=78uG, which is
expected to be accurate within a factor of two. The measured
mass-to-flux parameter is λ=0.95, indicating that the core is
in a transcritical regime.
Description:
Analysis of the polarized dust thermal emission in the Class 0
protostar IRAS 15398-3359. The data were acquired with the SOFIA/HAWC+
instrument, using the chop/nod method.
Objects:
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RA (2000) DE Designation(s)
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15 43 02.21 -34 09 07.7 IRAS 15398-3359 = IRAS F15398-3359
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 122 3 List of fits maps
fits/* . 3 Individual fits maps
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 50 A23 "datime" Obs.date Observation date
52- 54 I3 Kibyte size Size of FITS file
56- 83 A28 --- FileName Name of FITS file, in subdirectory fits
85-122 A38 --- Title Title of the FITS file
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Acknowledgements:
Elena Redaelli, eredaelli(at)mpe.mpg.de
(End) Elena Redaelli [MPE, Germany], Patricia Vannier [CDS] 21-Oct-2019