Astrometry of 6.7 GHz Methanol Maser toward W3(OH) with Japanese VLBI Network

We present the results of multi-epoch VLBI observations for 6.7 GHz methanol maser emission toward the UC HII region of W3(OH) with Japanese VLBI Network (JVN) [1]. Based on phase-referencing VLBI astrometry, we derived the trigonometric annual parallax to be 0.598 ± 0.067 mas, corresponding to a distance of 1.67 +0.21 kpc. This is the first detection of parallax for a 6.7 GHz methanol maser source with JVN, following European VLBI Network [2], and demonstrates that JVN/VERA is capable of conducting VLBI astrometry for 6.7 GHz methanol maser sources within a few kpc from the Sun. Based on in-beam mapping of the W3(OH) methanol maser, we also measured the internal proper motions of its 6.7 GHz methanol maser for the first time. The internal proper motions basically show north-south expansio