SEGUE: A SPECTROSCOPIC SURVEY OF 240,000 STARS WITHg= 14-20

Abstract

The Sloan Extension for Galactic Understanding and Exploration (SEGUE) Survey obtained ≈240,000 moderateresolution (R ∼ 1800) spectra from 3900 Å to 9000 Å of fainter Milky Way stars (14.0 < g < 20.3) of a wide variety of spectral types, both main-sequence and evolved objects, with the goal of studying the kinematics and populations of our Galaxy and its halo. The spectra are clustered in 212 regions spaced over three quarters of the sky. Radial velocity accuracies for stars are σ (RV) ∼ 4 km s −1 at g < 18, degrading to σ (RV) ∼ 15 km s −1 at g ∼ 20. For stars with signal-to-noise ratio >10 per resolution element, stellar atmospheric parameters are 4377 4378 YANNY ET AL.Vol. 137 estimated, including metallicity, surface gravity, and effective temperature. SEGUE obtained 3500 deg 2 of additional ugriz imaging (primarily at low Galactic latitudes) providing precise multicolor photometry (σ (g, r, i) ∼ 2%), (σ (u, z) ∼ 3%) and astrometry (≈0 .1) for spectroscopic target selection. The stellar spectra, imaging data, and derived parameter catalogs for this survey are publicly available as part of Sloan Digital Sky Survey Data Release 7.

The Milky Way's rotation curve out to 100 kpc and its constraint on the Galactic mass distribution

“…SDSS/SEGUE survey, a Galactic extension of the SDSS-II/III surveys, has obtained a total of about 360,000 optical (λλ3820-9100), low resolution (R ∼ 2000) spectra of Galactic stars at different distances, from 0.5 to 100 kpc (Yanny et al 2009). The spectra are processed with SEGUE Stellar Parameter Pipeline (SSPP; Lee et al 2008a,b;Allende Prieto et al 2008;Smolinski et al 2011), providing estimates of stellar parameters and V los .…”

“…In this paper, we report a newly constructed RC of our Galaxy, the Milky Way, extending out to 100 kpc, derived from ∼ 16, 000 primary red clump giants (PRCGs) selected from the LAMOST Spectroscopic Survey of the Galactic Anti-centre (LSS-GAC; Liu et al 2014;Yuan et al 2015) and the SDSS-III/APOGEE survey (Eisenstein et al 2011;Majewski et al 2015) in the (outer) disc, as well as from ∼ 5700 halo K giants (HKGs) selected from the SDSS/SEGUE survey (Yanny et al 2009) for the halo region. The usage of PRCGs in deriving the RC in the outer disc region help solve the above described two issues neatly.…”

Are ancient dwarf satellites the building blocks of the Galactic halo?

“…We recall here a number of ongoing and planned spectroscopic MW survey, such as RAVE (Steinmetz et al 2006), SEGUE (Yanny et al 2009), APOGEE (Majewski et al 2010), HERMES (Freeman 2010), Gaia-ESO (Gilmore et al 2012).…”

Tracing the Evolution of High-Redshift Galaxies Using Stellar Abundances

“…Comparison of the synthesized stellar metallicity distributions to observational data allows for the evaluation of our modeland allows us to place constraints on the parameters we have chosen to investigate. We compare our results to the limited set of elemental-abundance ratios ([Mg/Fe], [C/Fe]) determined for the large sample of low-resolution stellar spectra from the SEGUE database (Yanny et al 2009)and to the much smaller sample of metal-poor stars with available high-resolution spectroscopic elemental-abundance ratios assembled by Frebel (2010). Figure 3,with observational data from SEGUE (Yanny et al 2009) and Frebel (2010) overplotted in red and yellow, respectively.…”

“…The interpretation of these data will require a model that incorporates as many relevant physical processes as possible while still maintaining computational efficiency. We are currently able to compare to observational data from SEGUE (Yanny et al 2009) and the high-resolution stellar abundance measurements collected by Frebel (2010). We make quantitative comparisons between our model and observations, allowing for constraints on model parameters such as the nature of the stellar initial mass function (IMF), the efficiency with which gas forms stars, and the accuracy of theoretical stellar yields.…”