Milky Way Abundance Gradients from SDSS-III/APOGEE Observations
Abstract
We present initial abundance gradients in the Milky Way as determined from high-resolution (R > 20,000) spectra of red giant stars. Our observations were taken with the SDSS-III APO Galactic Evolution Experiment (APOGEE) and have a S/N of at least 100. APOGEE is able to sample a large range of Galactocentric radii (RGC) including the bulge and inner disk regions of the galaxy by working in the near-IR. From a sample of nearly 30,000 stars taken during the first year of APOGEE operation, we estimate distances using spectroscopically-derived surface gravities combined with extinction estimates from near- and mid-IR photometry. This sample includes stars with 0 < RGC < 20 kpc, and is constrained to a range of heights about the plane, Z, from 0 to 2 kpc. We determine radial abundance gradients for subsamples that include different heights about the plane and different [α/Fe] ratios. We find that the radial abundance gradient is steeper in the plane than above it for stars with near-solar [α/Fe], and mostly flat for stars with higher [α/Fe] at all Z.
- Publication:
-
American Astronomical Society Meeting Abstracts #221
- Pub Date:
- January 2013
- Bibcode:
- 2013AAS...22125414H