RR Lyrae stars as tracers of stellar populations in the galactic bulge, Andrea Kunder (CTIO)

I use a new catalog of Galactic bulge field RR Lyrae variables to explore the structure of the Milky Way Galaxy. The catalog contains 3667 RR0 Lyrae stars from the eight-year MACHO Project light-curve database. I first use these stars to make a reddening map of the central Galactic region. These reddenings are based upon my findings that the mean dereddened RR Lyrae color at minimum light is                (V − R)min,0 = 0.28 ± 0.02 mag, which is determined from new observations of 18 local RR Lyrae variables as well as 14 RR Lyrae from the literature.  Next, I find metallicities of the RR Lyrae stars from the Fourier coefficients of their light-curves, which are accurate to      ± 0.2 dex. Hence their absolute magnitudes and distances can be found. A correlation between metallicity and galactocentric distance is found.  I searched for the evidence of the Galactic bar, and found marginal evidence of a bar. This suggests that the RR Lyrae in the bulge represent a different population than the majority of the bulge stars, which are metal rich and are part of a bar.