Inside Out: The Stellar Kinematics and HI Map of DDO 46

This poster will present the optical and radio data for the dwarf galaxy DDO 46. From this information we can hypothesize the three dimensional structure of the galaxy. Through compiling these data, clues to the formation and evolution of dwarf galaxies can be surmised. The optical information was taken with the Mayall 4-meter + Echelle spectrograph at the National Optical Astronomy Observatory’s Kitt Peak National Observatory. It was then reduced, which gave one-dimensional spectra of the stars in the disk of DDO 46. These spectra were cross-correlated with nearby radial velocity standard stars within the Milky Way. This method allowed us to derive the stellar velocities and velocity dispersions, σz, of DDO 46. The results of the Karl G. Jansky Very Large Array high resolution HI emission data provided integrated intensity and velocity maps that were used to find the maximum rotational velocity, Vmax, of DDO 46. By combining the optical and radio data, we ascertained a kinematic measure, Vmax/σz that quantified the three-dimensional shape of the system. The reduced HI radio data observed with the Robert C. Byrd Green Bank Telescope shows the extended, tenuous neutral hydrogen environment around DDO 46, which can potentially reveal recent interactions, mergers, or gas accretion.