Revealing the structure of the Milky Way via parallax observations of maser sources
By Katharina Immer (Joint Institut for VLBI ERIC)
Thursday 23 Jan
Place: DAM Seminar (724)
Edwin Hubble showed in 1926 that galaxies can be classified into three groups depending on their shape: ellipticals, spirals and irregulars. We know that our own Galaxy has a spiral shape. However, the details of the galactic structure like the number of spiral arms or their exact location are still under debate. In the first part of this talk, I will present recent efforts to unveil the structure of our Milky Way, a complicated endeavour due to our position in the Galaxy. I will introduce the Bar and Spiral Structure Legacy (BeSSeL) survey and show how we used observations of maser sources in star-forming regions via the parallax method to pinpoint the Milky Way's spiral arms. I will also present some recent comparisons between BeSSeL and Gaia results. In the second part of the talk, I will focus on the Scutum spiral arm. With proper motion observations of maser sources we revealed a group of star-forming regions with large peculiar motions which are oriented towards the Galactic Centre. I will discuss our hypothesis that these motions are caused by the gravitational potential of the Galactic bar.