SEGUE Target Selection on-going SEGUE observations

SEGUE Target Selection

on-going SEGUE observations

SDSS/SEGUE status as of Nov. 10, 2004 Black= completed stripe or plate pair

1002/3900 sq deg imaging: 25% complete, 34/400 plates 8.5% complete.

SEGUE Imaging Aug-Oct 2004:

Aug 2004 1260 N 38 sq deg 291 N 104 Sep 2004 1100 N 105 1260 S 60 1100 S 107 72 S 117 72 N 62Oct 2004 72 N 55 1300 N 52 1300 S 47 --------------------- 747 sq deg + earlier scans: 255--------------------- 1002 sq deg 25% of SEGUE goal

Drillable imaging(filled Stripes N&S): 1100 N&S 200 sq. 1220 N&S 175 sq. portions of: 72 N&S 200 sq. 1300 N&S 40 sq. Stripes 1100&72were scanned in Aug/Sep and targetted/drilled for Nov/Dec observing(6 week turnaround)

SEGUE imaging sampleColor-Magnitude diagramsin 10 square degree boxestowards one direction on the sky...

Color-Magnitude (g-r,g) diagram for Strip 1260N

Dual turnoffs,indicates stream(s?) at10 and 20 kpcfrom the sun.

Thick Disk Fs

Halo or stream(s)?

Thin disk M stars

SEGUE spectroscopic sample:Radial Velocities of populationsof similar stars, Metalicity, Teff, log g determinations

Kinematic, Chemical populationstudies of the Milky Way and halo

25 WD150 A/BHB200 F 375 G III +V150 Low Metals100 K III100 K V 30 sdM (and L/T candidates) 10 AGB 10 Cool Wds

SEGUE target selection currently has 11 categories, freshly reviewed,and aims to observe a total of 240,000 stars arount the sky.Samples of the stellar categories:

Numbersindicateallocationof fibersby spectraltype perplate pair.

SEGUE spectroscopy to date:

Aug 2004: 8 Bright, 8 Faint Sep 2004: 7 Bright, 6 Faint Oct 2004: 3 Bright, 2 Faint --------------------------- 18 B 16 F 34/400 Plates done = 8.5% of SEGUE goal 43.6 plate equivalents

To date we have approx. 16,000 classified spectra, groupedin these categories (approximately):1500 A/BHBs, 3000 F, 6000 G, 150 K giants, 1500 K dwarf,300 WD, 800 M dwarf, 2500 Low Metal candidates (F-K),plus assorted QSOs and stars of unknown type.

White Dwarf

Cool White Dwarf Candidate

BHB Star, probe outer halo, streams to 150 kpc

F turnoff star, trace streams, halo, low [Fe/H] to 20kpc

G dwarf, largest SEGUE sample, probe disk/inner halo 1.5kpc to 8 kpc distances, Stream Giants also here

G dwarf Radial Velocity histograms, by Magnitude (dist)-250 -200 -150 -100 -50 0 50 km/s

K Giants - probe halo to 200 kpc, total Mass of MW,

K dwarf , kinematics from match to USNO-B, +RVphotometric parallax – probe disks from 0.5 – 2 kpc

Low metalicity candidate, [Fe/H] = -2.6, g=15.8, g-r=0.47Pop III exploration, gradients in inner/outer halo

LowerMetalsthan thelowest metalicity Globular cluster!

M dwarfs, M,L,T dwarf candidates, M sub-dwarf candssample of halo M dwarfs vs. low-metal F's

AGB candidate, Giants in Sagittarius/Monoceros streams?g = 16.5,g-r =1.12, u-g = 3.1, RV= -72km/s d(AGB) = 18 kpc

K Giant:Narrowerlines, featuresless deep.

K dwarfStrongerfeatures,broaderlines.

How to tella (distant)K giant froma (nearby)K dwarf, usingSDSS/SEGUEspectra.

Sun

SEGUE K giant stars usedto probe halo to d> 50 kpc

Using thespectrato separategiants from dwarfs,one can explorehalo structurewith K giants.

To test ability todetermine metalicity ofstars from SDSS/SEGUEspectra, we obtainspectra of objects withknown Metals [Fe/H] = -1.6

Target cluster stars separate well fromfield stars, with spread of 1 sigma = 0.25 dex.

+1

0

-1[Fe/H]-2

-3Radial Velocity

g-r

g

With atmosphericparameters determinedfor stars, one can go fromobserved 'color-magnitude'diagrams to...

Physical Hertzsprung-Russell diagrams:

Green: cluster giantsRed: Field starsYellow: Proper motiondefinite cluster matches Teff

surface gravity

g-r

g

SEGUE is doing well with thegrant of Fall season observingduring the last full year of SDSS-I.This 2004 data is available to all SDSS participants for analysisand papers.