SEGUE Target Selection

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SEGUE Target Selection on-going SEGUE
observations DR3 Update
SDSS Collaboration Meeting Sep 30, 2004 Pittsburgh
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DR3 Update DR3 CASDAS is now public 141
Million objects (Galaxies, QSOs,Stars) 480,000
unique spectra, 5000 square degrees Something
like 12,000 SQL queries attempted per day,
worldwide to the CAS. Approx 18 Tbytes
transferred from DASCAS (DR1DR2). 2 help-desk
queries/day. Lots of Papers appearing. Plunge
in! Don't wait!!
www.sdss.org/dr3
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Somebody's (not Hawking's) theorem says
'Information' in Astrophysics is of a 'Fractal'
nature. Cosmological and large scale structure
studies are of great interest, but the
objects are so far away, it's hard to get lots of
detail. With the Galaxy, we can get lots of
detail on each star. SEGUE part of SDSS-II hopes
to do for Galactic Studies what SDSS-I has done
for Large scale structure and galaxy/quasar
work. Key project SEGUE science drivers 1. Map
Halo structure trace streams such as the
Sagittarius and Monoceros-- Canis Major streams
around the Galaxy. Constrain Dark Matter
potential/shape. 2. Disk(s) Structure Study
the thin/thick disk transition, and the
transition to the halo/spheroid in number counts
(model parameters scale lengths, falloffs w/
radius, metalicities, kinematics and formation
history.
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SEGUE as of September 30, 2004 Black completed
stripe or plate pair 750/3900 sq deg imaging
19 complete, 29/400 plates 7 complete.
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History of SEGUE observations (data thru Jun 2004
is under SDSS) June-July 2003 Stripe 1220
(175 square deg) Oct-Nov 2003 4 SEGUE test
plates, RV test, super sky test June-July 2004
Refine SEGUE TS algorithm (v2_0), design layout
of 3900 sq degrees and 400 plates
Strip 205N (Sag) 80 sq deg Aug 2004 17
SEGUE plates observed 35 sq
deg Strip 1260 N Sep 2004 12 SEGUE plates
observed Strip 291N (cross) 50
sq deg Stripe 1100 NS 200 sq
deg Strip 1260 S 40 sq deg
Stripe 72 NS 100 sq deg
Plan going forward Oct 2004 Observe M15/M2
Globular Cluster Metalicity standard plates Oct
20, 2004 Refine SEGUE TS (v3_0), design plates
for Nov, Dec
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'57' varieties of Science projects with
SEGUE 1. Shape/Orientation of the Dark Matter
Halo 2-11. Structure of the Thick Disk (scale
length), is it a puffed-up Thin Disk or an
independent structure (big merger), some of
each? 12. Estimate of the Mass of the Galaxy,
within say r100 kpc from center (Rvs of distant
stars). 13-18. Merger history of the
Galaxy 19-27. Chemical Evolution of the Galaxy.
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28-35. GC's go down to Fe/H -2.2 or so, BUT
NO LOWER!! But, Field stars in the halo go down
to Fe/H -3, and even down to Fe/H -4.
Why is this? What does it mean? Is this Pop
III? 36-38. Chemical gradients in the halo and
disks? How strong are they? With precision
photometry and spectroscopy we can measure
this around the Galaxy. 39. Dark Matter
Clumpiness affects stream orbits.
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40-43. Proper motions (from USNO-2B) catalog add
greatly to investigation of thin/thick disk
kinematics,supplemented by Radial Vels and
photometric parallaxes of G and K stars.
Complete velocity ellipsoid information within
1kpc of sun is available. 44-49. Rare stellar
type catalogs White dwarfs Cool white dwarf
candidates M sub-dwarfs (halo metalicies and
kinematics) L,Tdwarf candidates at lower b
than regular SDSS survey. AGB stream red
giants
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50-51. Trace the most distant BHBs and K
giants, potentially out to several hundred
kpc from Galactic center, if they are there.
52-54. Probe into the murk of very low b lt 8
deg. 55-56. Star forming regions, open
clusters, IMF studies. Extinction and reddening
model refinements. 57. First year of SEGUE will
not worry about the (difficult to process and
interpret) very low latitude data, out years will
take up the challenge. Come to the meeting if
you are interested in this.
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SEGUE imaging sample Color-Magnitude diagrams in
10 square degree boxes towards one direction on
the sky...
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SEGUE as of September 30, 2004 Black completed
stripe or plate pair
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(No Transcript)
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Dual turnoffs, indicates stream(s?) at 10 and 20
kpc from the sun.
Thick Disk Fs
Thin disk M stars
Halo or stream(s)?
Color-Magnitude (g-r,g) diagram for Strip 1260N
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SEGUE spectroscopic sample Radial Velocities of
populations of similar stars, Metalicity, Teff,
log g determinations Kinematic, Chemical
population studies of the Milky Way and halo
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WD A/BHB F Turnoff G III V Low Metals K III K
V M V AGB Cool Wds
Spectroscopic targets selected to probe variety
of distances from the sun from lt 1 kpc to gt 100
kpc, basically through a 'standard candle' color
cut to select stars representative of each
distance.
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WD A/BHB F Turnoff G III V Low Metals K III K
V M V AGB Cool Wds
SEGUE currently has 10 categories and aims to
observe a total of 240,000 stars arount the
sky. Samples of the stellar categories
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White Dwarf
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Cool White Dwarf Candidate
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BHB Star, probe outer halo, streams to 150 kpc
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F turnoff star, trace streams, halo, low Fe/H
to 20kpc
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G dwarf, largest SEGUE sample, probe disk/inner
halo 1.5kpc to 8 kpc distances, Stream Giants
also here
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-250 -200 -150 -100 -50 0 50
km/s
G dwarf Radial Velocity histograms, by Magnitude
(dist)
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K Giants - probe halo to 200 kpc, total Mass of
MW,
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K dwarf , kinematics from match to USNO-B,
RV photometric parallax probe disks from 0.5
2 kpc
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Low metalicity candidate, Fe/H -2.6, g15.8,
g-r0.47 Pop III exploration, gradients in
inner/outer halo
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M dwarfs, M,L,T dwarf candidates, M sub-dwarf
cands sample of halo M dwarfs vs. low-metal F's
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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
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SEGUE is doing well with the grant of Fall season
observing during the last full year of
SDSS-I. This 2004 data is available to all SDSS
participants for analysis and papers.
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We are 'new' to the rich field of stellar
kinematic and population analysis, with
implications for dark matter and galaxy history
studies on the Galaxy easiest to observe. We
need your help! Meeting Oct 2 There are many
opportunities to contribute, including student
projects.
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-44 -41 -38
-35 -32 -29
-26 -23 -20
-17 -14
-11
Strip 1100S (l50 deg) CMDs (g-r,g)
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K Giant Narrower lines, features less
deep. K dwarf Stronger features, broader l
ines.
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1100S Binned 6x3deg
Photo in crowded fields as we pass thru b
0 plane, will be improved in SEGUE outyears.
-43 -37 -31
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l 50 deg at 4 b's. Possible stream
present, but need to model spheroid.
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SEGUE footprint as of Sep 30, 2004 Black
completed stripe/plate 29/400 plates 7 done.