2006ApJ...648..340L


C.D.S. - SIMBAD4 rel 1.7 - 2020.11.29CET01:05:30

2006ApJ...648..340L - Astrophys. J., 648, 340-354 (2006/September-1)

Results of SPARO 2003: mapping magnetic fields in giant molecular clouds.

LI H., GRIFFIN G.S., KREJNY M., NOVAK G., LOEWENSTEIN R.F., NEWCOMB M.G., CALISSE P.G. and CHUSS D.T.

Abstract (from CDS):

We present results from the Austral Winter 2003 observing campaign of SPARO, a 450 µm polarimeter used with a 2 m telescope at the South Pole. We mapped large-scale magnetic fields in four GMCs in the Galactic disk: NGC 6334, the Carina Nebula, G333.6-0.2, and G331.5-0.1. We find a statistically significant correlation of the inferred field directions with the orientation of the Galactic plane. Specifically, three of the four GMCs (NGC 6334 is the exception) have mean field directions that are within 15° of the plane. The simplest interpretation is that the field direction tends to be preserved during the process of GMC formation. We have also carried out an analysis of published optical polarimetry data. For the closest of the SPARO GMCs, NGC 6334, we can compare the field direction in the cloud as measured by SPARO with the field direction in a larger region surrounding the cloud, as determined from optical polarimetry. For purposes of comparison, we also use optical polarimetry to determine field directions for 9-10 other regions of similar size. We find that the region surrounding NGC 6334 is an outlier in the distribution of field directions determined from optical polarimetry, just as the NGC 6334 cloud is an outlier in the distribution of cloud field directions determined by SPARO. In both cases the field direction corresponding to NGC 6334 is rotated away from the direction of the plane by a large angle. This finding is consistent with our suggestion that field direction tends to be preserved during GMC formation. Finally, by comparing the disorder in our magnetic field maps with the disorder seen in magnetic field maps derived from MHD turbulence simulations, we conclude that the magnetic energy density in our clouds is comparable to the turbulent energy density.

Abstract Copyright:

Journal keyword(s): Galaxies: Magnetic Fields - ISM: Clouds - ISM: Magnetic Fields - Polarization - Turbulence

Simbad objects: 14

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Number of rows : 14

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME Car Arm PoG 10 00 -60.0           ~ 384 1
2 NAME Carina I HII Region HII 10 43 32 -59 35.0           ~ 51 0
3 GAL 287.4-00.6 MoC 10 43 35 -59 35.5           ~ 5 0
4 NGC 3372 HII 10 44 19.0 -59 53 21           ~ 904 2
5 GAL 287.6-00.6 MoC 10 44 47 -59 39.3           ~ 3 0
6 NAME Car II HII Region HII 10 44 47 -59 38.8           ~ 35 0
7 NAME Crux Arm PoG 12 30 -60.0           ~ 85 0
8 NAME Car-Sgr Arm PoG 15 00 -40.0           ~ 434 1
9 GAL 331.5-00.1 HII 16 12 09.8 -51 27 06           ~ 27 0
10 GAL 331.31-00.34 HII 16 12 23 -51 46.5           ~ 8 0
11 GAL 333.6-00.2 HII 16 22 11 -50 05.6           ~ 141 0
12 NGC 6334 HII 17 20 51 -36 06.9           ~ 595 0
13 NAME NGC 6334-I Cl* 17 20 53.35 -35 47 01.5           ~ 278 0
14 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1955 1

    Equat.    Gal    SGal    Ecl

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2020.11.29-01:05:30

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