NOAO >   Observing Info >   Approved Programs >   2016B-0081

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Program Information for 2016B-0081


PI: Kevin Schlaufman, Carnegie Institution of Washington, kschlaufman@jhu.edu
Address: Observatories, 813 Santa Barbara St, Pasadena, CA 91101 USA

CoI: Andrew Casey, University of Cambridge
CoI: Melissa Ness, Max Planck Institut fur Astrophysik

Title: The Most Promising Search for the Galaxy's Oldest Stars

Abstract: be used to investigate ancient stellar populations and supernovae as well as the formation of the Milky Way. The oldest stars in the Galaxy are thought to be metal-poor stars in the bulge. However, extinction and stellar crowding preclude traditional searches for metal-poor stars in the inner Galaxy. Instead, searches for the oldest stars have predominantly focused on the halo and dwarf galaxies. We have developed an efficient selection that uses 2MASS and IRAC near- and mid-infrared photometry to identify metal-poor stars. Our selection is as efficient as classical techniques, yet is minimally impacted by crowding and extinction and is therefore well suited to the inner Galaxy. We were awarded AAT/AAOmega time through the European OPTICON TAC in 2015A, and those observations identified 10 EMP stars (i.e., $-4.0 lesssim mathrm{[Fe/H]} lesssim -3.0$) and 200 very metal-poor stars (i.e., $- 3.0 lesssim mathrm{[Fe/H]} lesssim -2.0$) in the bulge. These stars are rare. Indeed, before our observations only 27 bulge stars with [Fe/H] $lesssim -2.0$ from high-resolution observations had been reported in the literature. Our sample is extensive, yet spatially incomplete: variable weather conditions forced us to focus our 2015 efforts on the outer bulge. We request 3 nights with AAT/AAOmega to observe most of our remaining candidates. We expect to find $sim!!100$ EMP stars, possibly including the first Population III star ever discovered.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2016B):  AAT/AAOmega -- 2n on Aug 02 - Aug 05 2016


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