LBA observations for project V255 semester 2021APRS

The primary aim of this project is to use VLBI observations to measure accurate distances to, and proper motions of 6.7 GHz methanol masers in the third and fourth quadrants of the Galaxy. These observations will allow us to improve our knowledge of the structure of the Galaxy and complements a similar study being done in the northern hemisphere looking at methanol and water masers in the first and second quadrants. Parallax measurements for 100 northern sources show that the Milky Way appears to have nearly identical rotational properties, as well as a similar dark matter halo size and mass to those of the Andromeda galaxy. However, the results are derived from sources within a limited Galactic longitude range and measurements of parallax and proper motion for high-mass star forming regions in the southern sky of the Milky Way are critical to better constrain measurements of critical parameters such as the circular rotation speed of the Sun about the Milky Way.