Physics and Astronomy Colloquium
Mapping the Milky Way in two and three dimensions
Presented by Andreas Brunthaler Astronomer in the Millimeter & Submillimeter Astronomy Group at the Max-Planck-Institut für Radioastronomie
n my talk, I will present results from two recent large radio survey of
the Milky Way. The GLObal View on STAR formation (GLOSTAR) Survey is a
C-Band (4-8 GHz) survey of 145 square degrees of the Northern Galactic
Plane conducted with the Karl G. Jansky Very Large Array in multiple
configurations and the Effelsberg 100-m telescope. We not only observed
the radio continuum emission in full polarization, but also the 6.7 GHz
methanol maser transition, the 4.8 GHz formaldehyde line, as well as
several radio recombination lines. This provides for the first time a
radio survey covering all angular scales down to 1.5 arcsec, similar to
complementary NIR/MIR Galactic Plane surveys. This survey of the
Galactic plane detects tell-tale tracers of star formation: compact,
ultra- and hyper-compact Hii regions and molecular masers which trace
different stages of early stellar evolution and pinpoints the very
centers of the early phase of star-forming activity.
The Bar and Spiral Structure (BeSSeL) Survey is measuring accurate
distances and proper motions of high mass star forming regions across
the Milky Way using the Very Long Baseline Array. The target sources are
methanol and water masers that are associated with young massive stars
and compact HII regions that trace spiral structure. With accurate
distance measurements we locate the spiral arms, and with absolute
proper motions we can determine the 3-dimensional motions of these
massive young stars. Modeling the absolute proper motions gives very
accurate measurements of fundamental Galactic parameters, such as the
distance to the Galactic center (Ro), the rotation velocity at the Sun
(Θo), and the rotation curve of the Milky Way.
3:30 pm, Friday, October 9, 2020
Zoom,
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