Measuring Magnetic Fields from Water Masers Associated with a Synchrotron Protostellar Jet

Date Issued
2018
Author(s)
•
DOI
Abstract
The Turner-Welch Object in the W3(OH) high-mass star forming complex drives a synchrotron jet, which is quite exceptional for a high-mass protostar, and is associated with a strongly polarized water maser source, W3(H2O), making it an optimal target to investigate the role of magnetic fields on the innermost scales of protostellar disk-jet systems. We report here full polarimetric VLBA observations of water masers. The linearly polarized emission from water masers provides clues on the orientation of the local magnetic field, while the measurement of the Zeeman splitting from circular polarization provides its strength. By combining the information on the measured orientation and strength of the magnetic field with the knowledge of the maser velocities, we infer that the magnetic field evolves from having a dominant component parallel to the outflow velocity in the pre-shock gas (with field strengths of the order of a few tens of mG), to being mainly dominated by the perpendicular component (of order of a few hundred of mG) in the post-shock gas where the water masers are excited. The general implication is that in the undisturbed (i.e. not-shocked) circumstellar gas, the flow velocities would follow closely the magnetic field lines, while in the shocked gas the magnetic field would be re-configured to be parallel to the shock front as a consequence of gas compression.
Coverage
Astrophysical Masers: Unlocking the Mysteries of the Universe
All editors
Tarchi, Andrea; Reid, Mark J.; Castangia, Paola
Series
Volume
336
Start page
215
Conferenece
IAUS 336: Astrophysical Masers: Unlocking the Mysteries of the Universe
Conferenece place
Cagliari, Italia
Conferenece date
4-8 Settembre, 2017
Uri
Url
Issn Identifier
1743-9213
Ads BibCode
2018IAUS..336..215G
Rights
open.access
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