J/A+A/544/A69 CN(1-0) Zeeman observations of NGC 2264-C (Maury+, 2012)
CN Zeeman observations of the NGC 2264-C protocluster.
Maury A.J., Wiesemeyer H., Thum C.
<Astron. Astrophys. 544, A69 (2012)>
=2012A&A...544A..69M 2012A&A...544A..69M
ADC_Keywords: Spectroscopy ; Radio lines ; Polarization ; Molecular clouds
Keywords: stars: formation, circumstellar matter - magnetic fields -
polarization - ISM: individual objects: NGC 2264
Abstract:
From an observational point of view, the role of magnetic fields in
star formation remains unclear, and two main theoretical scenarios
have been proposed so far to regulate the star-formation processes.
The first model assumes that turbulence in star-forming clumps plays a
crucial role, and especially that protostellar outflow-driven
turbulence is crucial to support cluster-forming clumps; while the
second scenario is based on the consideration of a
magnetically-supported clump. Previous studies of the NGC 2264-C
protocluster indicate that, in addition to thermal pressure, some
extra support might effectively act against the gravitational collapse
of this cluster- forming clump. We previously showed that this extra
support is not due to the numerous protostellar outflows, nor the
enhanced turbulence in this protocluster. Here we present the results
of the first polarimetric campaign dedicated to quantifying the
magnetic support at work in the NGC 2264-C clump. Our Zeeman
observations of the CN(1-0) hyperfine lines provide an upper limit to
the magnetic field strength Blos<0.6 mG in the protocluster (projected
along the line of sight). While these results do not provide
sufficiently tight constraints to fully quantify the magnetic support
at work in NGC 2264-C, they suggest that, within the uncertainties,
the core could be either magnetically super or sub-critical, with the
former being more likely.
Description:
The Fits file contains the CN(1-0) spectra obtained from the mapping
of the NGC2264-C protocluster with the IRAM-30m telescope, as
described in section 2.1. The spectral resolution is 0.8km/s and the
bandwidth covers the nine hyperfine components of the CN(1-0)
transition, as reported in Table 1. The intensity scale is expressed
in antenna temperatures (Ta*).
Objects:
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RA (2000) DE Designation(s)
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06 41 11 +09 29.1 NGC 2264-C = NAME Mon OB1 C
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
map.dat 79 1 Infomations on cnmap.fit file
cnmap.fit 2880 1545 NGC2264-C CN(1-0) spectra
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Byte-by-byte Description of file: map.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- 23 F4.1 arcsec/pix scale Scale of the image
25- 26 I2 pix Nx Number of pixels along X-axis
27 A1 --- --- [x]
28- 29 I2 pix Ny Number of pixels along Y-axis
30 A1 --- --- [x]
31- 34 I4 --- Nz Number of slices (velocity)
36- 69 A34 -- Com Comments
71- 79 A9 --- FileName Name of FITS file
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Acknowledgements:
Anaelle Maury, amaury(at)eso.org
(End) Patricia Vannier [CDS] 27-Jun-2012