出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The first extension of the Sloan Digital Sky Survey (SDSS-II), which included the program
SEGUE: Sloan Extension for Galactic Understanding and Exploration, ended in July, 2008. This
effort, in which JINA was an institutional partner, has already produced the largest sample of
medium-resolution stellar spectra yet obtained. These data are revolutionizing our understanding
of the nature of the stellar populations of theMilkyWay, in particular that of the halo populations.
The JINA-developed SEGUE Stellar Parameter Pipeline (SSPP) has obtained estimates of the
atmospheric parameters (Teff , log g, [Fe/H]) for more than half of the spectra to date, totaling
in excess of 200,000 stars. Here we report on the distribution of stellar metallicity, [Fe/H], for
stars in the SDSS/SEGUE database with [Fe/H] < −2.0. This sample now exceeds 16,000 stars,
more than triple the number of such stars discovered by all previous surveys combined. We also
comment on the prospects for further increases in this sample in the near future, from the next
extension of SDSS (SDSS-III), which will include a full year of SEGUE operation fromJuly 2008
to July 2009, and additional “piggy back” observations of stars taken during subsequent years.
