# Presentation: 679574

## SEGUE  Target Selection

- on-going SEGUE observations
- DR3 Update

- SDSS Collaboration Meeting Sep 30, 2004
- Pittsburgh

## www.sdss.org/dr3

- DR3 CAS+DAS 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 DAS+CAS (DR1+DR2).
- 2 help-desk queries/day.
- Lots of Papers appearing.
- Plunge in!  Don't wait!!

## 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.

## SEGUE as of September 30, 2004

-   Black= completed stripe or plate pair
-  750/3900 sq deg imaging: 19% complete,
-    29/400 plates 7% complete.

## 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 N&S  200 sq deg
-                   Strip  1260 S  40 sq deg
-                   Stripe 72 N&S  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

## '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 r=100 kpc from center (Rvs of distant
- stars).
- 13-18. Merger history of the Galaxy
- 19-27. Chemical Evolution of the Galaxy.

## 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.

## 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

## 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| < 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].

## SEGUE  imaging sample

- Color-Magnitude diagrams
- in 10 square degree boxes
- towards one direction on the sky...

## SEGUE as of September 30, 2004

-   Black= completed stripe or plate pair

## Slide 12

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

- Dual turnoffs,
- indicates
- stream(s?) at
- 10 and 20 kpc
- from the sun.

- Thick  Disk Fs

- Halo or stream(s)?

- Thin disk M stars

## 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

## 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 < 1 kpc to > 100 kpc, basically through a 'standard candle' color cut
- to select stars representative of each distance.

## 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:

## White Dwarf 

- 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 

- 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, +RV

- photometric parallax – probe  disks from 0.5 – 2 kpc

## Low metalicity candidate,  [Fe/H] = -2.6, g=15.8, g-r=0.47

- Pop III exploration,  gradients in inner/outer halo

## M dwarfs, M,L,T dwarf candidates,  M sub-dwarf cands

- sample 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

## 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.

## 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.

## Strip 1100S  (l=50 deg)  CMDs (g-r,g)

- -44                 -41                -38                  -35
- -32                 -29                -26                 -23
- -20                 -17                -14                  -11

## K Giant:

- Narrower
- lines,
- features
- less deep.
- K dwarf
- Stronger
- features,
- broader
- lines.

## -43                       -37

- -31                        -25

- 1100S
- Binned
- 6x3deg

- l =50 deg
- at 4 b's.
- Possible
- stream
- present,
- but need
- to model
- spheroid.

- Photo
- in
- crowded
- fields
- as we
- pass thru
- |b| = 0
- plane,
- will be
- improved
- in SEGUE
- outyears.

## SEGUE footprint as of Sep 30, 2004

- Black= completed stripe/plate
- 29/400 plates 7% done.