F Turnoff Distribution in the Galactic Halo Using Globular Clusters as Proxies

Details F Turnoff Distribution in the Galactic Halo Using Globular Clusters as Proxies F Turnoff Distribution in the Galactic Halo Using Globular Clusters as Proxies

Jan 2012

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012aas...21943801n&link_type=abstract

American Astronomical Society, AAS Meeting #219, #438.01

Astronomy and Astrophysics

Astronomy

Scientific paper

F turnoff stars are important tools for studying Galactic halo substructure because they are plentiful, luminous, and can be easily selected by their photometric colors from large surveys such as the Sloan Digital Sky Survey (SDSS). We describe the absolute magnitude distribution of color-selected F turnoff stars, as measured from SDSS data, for eleven globular clusters in the Milky Way halo. We find that the absolute magnitude distribution of turnoff stars is intrinsically the same for all clusters studied, and is well fit by two half Gaussian functions, centered at μ = 4.18, with a bright-side σ = 0.36, and with a faint-side σ = 0.76. However, the color errors and detection efficiencies cause the observed σ of the faint-side Gaussian to change with magnitude due to contamination from redder main sequence stars (40% at 21st magnitude). We present a function that will correct for this magnitude-dependent change in selected stellar populations, when calculating stellar density from color-selected turnoff stars. We also present a consistent set of distances, ages and metallicities for eleven clusters in the SDSS Data Release 7. We calculate a linear correction function to Padova isochrones so that they are consistent with SDSS globular cluster data from previous papers. We show that our cluster population falls along the theoretical Age-Metallicity Relationship (AMR), and further find that isochrones for stellar populations on the AMR have very similar turnoffs; increasing metallicity and decreasing age conspire to produce similar turnoff magnitudes and colors for all old clusters that lie on the AMR.
This research was supported by NSF grant AST 10-09670 and the NASA/NY Space Grant.

Affiliated with

Also associated with

No associations

Rating

F Turnoff Distribution in the Galactic Halo Using Globular Clusters as Proxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with F Turnoff Distribution in the Galactic Halo Using Globular Clusters as Proxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and F Turnoff Distribution in the Galactic Halo Using Globular Clusters as Proxies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1585513