5 papers
An updated model for the Perseus Spiral Arm from Trigonometric Parallax and 3-dimensional kinematic distances of distant massive stars
Lucas J. Hyland, Mark J. Reid, Simon P. Ellingsen +3
We report trigonometric parallaxes and proper motions for three water masers and one methanol maser obtained with the VLBA as part of the BeSSeL Survey. Incorporating these paralla…
The Extraordinary Maser Flaring Event in the Massive Protostellar System NGC6334I: Multi-Epoch Milliarcsecond Resolution Investigation of the 6.7-GHz Methanol Masers
Jayender Kumar, Simon P. Ellingsen, Gabor Orosz +4
We report the first multi-epoch milliarcsecond resolution imaging of the 6.7-GHz class II methanol maser emission associated with the high-mass protocluster system NGC6334I. The ob…
First detections of methanol maser lines from a rare transition family
Bradley R. Johnson, Simon P. Ellingsen, Shari L. Breen +3
We report the first observations in a rare family of class II methanol maser transitions in both CHOH and CHOH toward three southern high-mass star formation regions…
Compact vs. Scattered: Suitability of Southern 6.7GHz Methanol Masers for VLBI astrometry
Lucas J. Hyland, Simon P. Ellingsen, Mark J. Reid
The 6.7~GHz methanol maser transition is exclusively associated with young, high-mass stars and represents a potential target for astrometric studies, including accurate determinat…
The Expanding 3 kpc Arms Are Neither Expanding nor Spiral Arms but X1 Orbits Driven by the Galactic Bar
Jayender Kumar, Mark J. Reid, T. M. Dame +6
Near the center of our Milky Way is a bar-like structure and the so-called Expanding 3-kpc arms. We currently have limited knowledge of this important region, since we are about 8.…