Physics
Scientific paper
Dec 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005phdt........22c&link_type=abstract
PhD Thesis, Proquest Dissertations And Theses 2005. Section 0090, Part 0606 135 pages; [Ph.D. dissertation].United States -- Ill
Physics
Star Formation, Magnetic Fields
Scientific paper
We observed DR21(OH) in dust continuum polarized emission at 3 mm and the CO J = 1 [arrow right] 0 polarized emission. Our continuum polarization results are consistent with previous observations. However, the direction of the linear polarization for the J = 1 [arrow right] 0 is perpendicular to previous CO J = 2 [arrow right] 1 polarization observations. This unexpected result was explored by obtaining numerical solutions to the multilevel, radiative transfer equations for a gas with anisotropic optical depths. We find that in addition to the anisotropic optical depths, anisotropic excitation due to a source of radiation that is external to the CO is needed to understand the orthogonality in the directions of polarization. The CO polarization must arise in relatively low density ([Special characters omitted.] ˜ 100 cm -3 ) envelope gas. We infer B ˜ 10μ G in this gas, which implies that the envelope is subcritical.
We detected dust and line polarized emission from NGC2071IR that was used to constrain the morphology of the magnetic field. From CO J = 2 [arrow right] 1 polarized emission we found evidence for a magnetic field in the powerful bipolar outflow present in this region. We estimated a visual extinction A v = 26 mag from our dust observations. This result seems to show that dust grains emit polarized radiation efficiently at higher densities than previously thought. Mechanical alignment by the outflow is proposed to explain the polarization pattern observed in NGC2071IR, which is consistent with the observed flattening in this source.
We present polarization maps of G30.79 FIR 10 (in W43) from thermal dust emission at 1.3 mm and from CO J = 2 [arrow right] 1 line emission. The G30.79 FIR 10 dust polarization map suggests an hourglass shape for the magnetic field. Application of the Chandrasekhar-Fermi method yielded B pos = 1.7 mG and a statistically corrected mass to magnetic flux ratio λ C = 0.9, or essentially critical.
We developed a code to model and observe the polarized dust emission from arbitrary magnetic field configurations in star forming regions. We found that the interferometric observation will strongly overestimate the fractional polarization under most cases; however, we found that the position angle is preserved with errors that are in the range of observable quantities.
No associations
LandOfFree
Magnetic fields in star forming regions: Interferometric mapping and modeling does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Magnetic fields in star forming regions: Interferometric mapping and modeling, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic fields in star forming regions: Interferometric mapping and modeling will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1467849