J/A+A/626/A36 ALMA continuum fits files of G9.62+0.19 (Dall'Olio+, 2019)
ALMA reveals the magnetic field evolution in the high-mass star forming complex
G9.62+0.19.
Dall'Olio D., Vlemmings W.H.T., Persson M.V., Alves F.O., Beuther H.,
Girart J.M., Surcis G., Torrelles J.M., Van Langevelde H.J.
<Astron. Astrophys. 626, A36 (2019)>
=2019A&A...626A..36D 2019A&A...626A..36D (SIMBAD/NED BibCode)
ADC_Keywords: H II regions ; Radio lines
Keywords: stars: formation - ISM: magnetic fields - magnetic fields -
polarization - stars: massive
Abstract:
We used Band 7 ALMA observations in full polarisation mode to analyse
the polarised dust emission of the massive star forming region
G9.62+0.19. We estimated the magnetic field strength via the
Davis-Chandrasekhar-Fermi and structure function methods. We resolve
several protostellar cores embedded in a bright and dusty filamentary
structure. The magnetic field is orientated along the filament and
appears perpendicular to the direction of the outflows. The
polarisation vectors present ordered patterns and the cores showing
polarised emission are less fragmented. We suggest an evolutionary
sequence of the magnetic field, and the less evolved hot core exhibits
a stronger magnetic field than the more evolved hot core. An average
magnetic field strength of the order of 11mG was derived, from which
we obtain a low turbulent-to-magnetic energy ratio, indicating that
turbulence does not significantly contribute to the stability of the
clump. We report a detection of linear polarisation from thermal line
emission, probably from methanol or carbon dioxide, and we tentatively
compared linear polarisation vectors from our observations with
previous linearly polarised OH masers observations.
Description:
ALMA continuum fits files of the G9.62+0.19 region observed in Band 7.
For the polarization analysis the region is divided in field North and
field South as discussed in the paper. POLI and POLA maps are provided
and the POLA map has the vectors masked below 4sigma in POLI (as
described in the paper). A line was detected at the frequency of
336.7GHz, presenting polarized emission. The residuals are after
subtracting the best fit for the cores.
Objects:
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RA (2000) DE Designation(s)
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18 06 13.9 -20 31 44 G9.62+0.19 = GAL 009.62+00.19
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 140 9 List of fits images
fits/* . 9 Individual fits images
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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- 53 A26 "datime" Obs.date Observation date
55- 61 F7.3 GHz Freq Observed frequency
63- 66 I4 Kibyte size Size of FITS file
68- 79 A12 --- FileName Name of FITS file, in subdirectory fits
81-140 A60 --- Title Title of the FITS file
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Acknowledgements:
Daria Dall'Olio, daria.dallolio(at)chalmers.se
(End) Daria Dall'Olio [Chalmers, Sweden], Patricia Vannier [CDS] 10-May-2019