Measuring Magnetic Fields from Water Masers Associated with the Synchrotron Protostellar Jet in W3(H2O)
Journal
Date Issued
2018
Author(s)
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
14th European VLBI Network Symposium & Users Meeting (EVN 2018)
Volume
344
Start page
39
Conferenece
14th European VLBI Network Symposium & Users Meeting (EVN 2018)
Conferenece place
Granada, Spagna
Conferenece date
8-11 Ottobre, 2018
Issn Identifier
1824-8039
Ads BibCode
2018evn..confE..39G
Rights
open.access
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