Physics & Astronomy ETDs

Publication Date

Spring 4-16-2018


The Bulge Asymmetries and Dynamical Evolution (BAaDE) survey is an SiO maser survey of 28,062 infrared-selected evolved stars primarily in the Galactic plane. By cross-matching the BAaDE target sources with nine different infrared catalogs, we have constructed a catalog with wavelength coverage from 0.71 to 80 m. Using this catalog, we fit the data for each source to a model spectral energy distribution (SED) generated with the radiation transport program DUSTY in order to obtain characteristics such as bolometric flux, source effective temperature, and the optical depth of the circumstellar envelope.

The overall goal of the BAaDE survey is to extract a gravitational potential in order to model Galactic dynamics, by providing line-of-sight velocities and positions for each source. The results would be greatly enhanced if, in addition to the positions and velocities, we could also provide a distance estimate. We explore a new method of estimating distances to the BAaDE sources by creating a series of template SEDs, differentiated by infrared color in the region of the spectrum covered by the Midcourse Space Experiment (MSX; 8.28 – 21.34 m). We calibrate the first of these template SEDs using similarly colored Red Giant stars with known parallax-distances, and obtain an empirical relation between the bolometric flux and distance of sources with similarly shaped SED.

Degree Name


Level of Degree


Department Name

Physics & Astronomy

First Committee Member (Chair)

Ylva Pihlstrom

Second Committee Member

Gregory Taylor

Third Committee Member

Mark Claussen




AGB, Galaxy, infrared, SiO maser survey, evolved stars, distance estimates

Document Type