Collaborative Research: Raising the Bar: Radio Investigations of the Structure and Dynamics of the Galactic Bulge

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

The investigators will search for red giant stars along the plane of our Milky Way galaxy, using radio telescopes. These stars have the remarkable characteristic of acting like ultra-bright lasers, emitting radio waves due to the molecule Silicon Monoxide (SiO), which is found in the environment surrounding this type of star. Because of this unique feature, radio telescopes can detect these stars at great distances, even when they are hidden in clouds of dust and gas. The investigators will use the stars to study the structure of our galaxy and understand how our Galaxy is being pulled by the gravity of other nearby galaxies and clusters of stars in our Galaxy. By looking for unusual motions of stars in the galaxy, the investigators can detect the past collisions of dwarf galaxies with our Galaxy. The investigators will test models for a key feature seen in our Galaxy, "the bar", a linear structure extending on both sides of the center of our Galaxy. The bar is thought to partially result from the gravitational pull of clusters of stars and gas. These clusters merged to become part of our Milky Way. In addition to the bar, our Galaxy also shows a "bulge" near the center, where stars reach high orbits. In our region of the galaxy the stars are concentrated in a disk. The researchers will provide student participation opportunities and education within the science, technology, engineering and math (STEM) disciplines. This includes finding minority students to work on the project and concentrating on strengthening female participation. Through this research award, graduate students will be trained and additional undergraduate students will be have to opportunity for summer research jobs. Specific science goals include the modeling of the dynamics and the structure of the Galactic bulge and the central galactic disk. This data will allow defining the relationship of the bar to the populations of the Galactic plane and Center, and the effect of the strongly boxy potential of the bulge on dynamics, and the presence of a ``long'' bar. In particular, both N-body models and self-consistent models will be compared with direct dynamical measurements from the stellar maser velocities. From near-infrared spectra elemental abundances and properties of the circumstellar envelopes will be determined. The investigator's studies will also be important for understanding the structure of all spiral galaxies. The Galactic bulge provides a unique laboratory, as it is the only place where detailed studies are possible for the processes taking place in many disk galaxies.