SEGUE Meeting

AM Talkstowards a task list:pipeline changes/updatesTarget Selection updates

SDSS Collaboration Meeting Oct 2, 2004Pittsburgh

Reminder: Key project SEGUE science drivers:

1. Map Halo structure – trace streams suchas the Sagittarius and Monoceros--Canis Major streams around the Galaxy.Constrain Dark Matter potential/shape.

2. Disk(s) Structure – Study the thin/thick disktransition, and the transition to the halo/spheroid in number counts (modelparameters scale lengths, falloffs w/ radius, metalicities, kinematics and formation history.

Over-arching Question:

Can the SEGUE imaging and spectroscopy meet the basic science goals, as laid out in the SEGUE white paper and various SEGUE proposals?

Fibers per plate Pair:

WD 25CWD 10BHB 125F TO 150G 375K III 125Low Fe150K V 125 Ms 50AGB 10

SKY 96QA 15RED/SP 16

Saturday Oct 2, 2004 AM (Room: Allen 318)

9:00 Intro

9:10 J. Bochanski SDSSWhite Dwarf/M-Dwarf pairs, red Star update

9:30 J. A. Smith Photometry Update, WD/MD stars

9:45 C. Rockosi Radial Velocities for SEGUE

10:15-10:45 Break

10:45 C. Allende-P. Metalicity, Gravity determination

11:15 R. Wilhelm Metalicity, Gravity determination – hot stars

11:45 T. Beers Atmospheric Parameter determination in stars

12:30-1:30 Lunch

1:30-3:30 Open discussion spectroscopic pipeline, SEGUE science4:00-5:30 SEGUE target selection category by category

Observing strategy:Imaging: 3900 sq deg, mostly at low |b|Spectra: 240,000 stellar spectra (520 plate-equivalents)of stars of a range of colors.

-44 -41 -38 -35

-32 -29 -26 -23

-20 -17 -14 -11

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

SEGUE Level 0 Deliverables:

Medium latitude frames (|b| > 10 deg) processed through PHOTO, initial calibration with PT patches to roughlySDSS-I accuracy (i.e. g-r errors of 2%). Flat file format ok (tsObj catalogs). [turn around in time for Target Selection: onemonth or one year time scales, can use SDSS-I imaging]

Target Selection Pipeline for SEGUE TS, with documentation, including usual TS items: skies, guide stars, redden standards,plPlugMapT input files.

Spectro plates processed through existing SDSS-I 2D+1D pipelines with improved Radial Velocities from ELODIE template fits (or equivalent) for all stars with S/N>~5.First-pass estimation of stellar atmos params:Teff, [Fe/H], log g for stars with g < ~18.5. 'Value added Catalog' format. Matches to existing Proper motion data when available.Design, observation, processing of 'calibration/standard'plates with stars of known [Fe/H], RV, log g, etc.

Enhanced Goals:

Imaging processing: Ability to process imaging in regions ofhigh stellar density (|b| < 10 deg), producing accurate catalogsstellar magnitudes and positions in these regions.

Calibration: Use crossing scans or other techniques toimprove photometry from ~2% RMS to ~1% with fewer outliers.

Spectroscopy: Incorporate parameter (i.e. [Fe/H]) estimationinto pipeline processing.

Database: Insert Imaging catalogs and spectra w/ allparameters (i.e. PPM matches, Rvs),into indexed database (i.e. CAS-style) in addition to DAS styleflat field access.

To Do List:

Great interest has been expressed by current andnew partners in SEGUE and the other SDSS-IIscience projects.

Note that we are currently effort limited, and need toorganize a team to handle development and operationsas well as science analysis aspects of SEGUE, andwe hope and expect to draw resources frommany of you.

Development tasks (broad categories: target selection, imaging, spectro, data processing, Q/A, calibration/standards, science analysis, database and distribution [and, of course, documentation]):

Target Selection tasks:

Refine, verify SEGUE Target Selection algorithm in each of the10 Stellar Categories (F turnoff, G dwarf, K giant, BHB/A, Low Metalicities)[There are at least projects for 10 people here!]:

[Weight low-metal stars to bright mags < 18, improve K-giantefficiency from current 20%]Are we selecting the right stars enough stars in each category todo the science (trace halo streams or disk structure, explore metalicityhistory of the Milky Way or Chemical gradients in the Galaxy.

Are we selecting enough stars in each category to have sufficient statisticsto do the science? [More F stars to trace streams?]

Web link to target selection color/mag cuts and links to early SEGUE plates.

(A more formal web page is coming)

http://www-sdss.fnal.gov/yanny/seguets/

Imaging: Plan, obtain and reduce SEGUE imaging stripe

data.

Analyze photometric accuracy as f(stellar density).Update imaging pipeline to work at high density

[i.e. stars-only 'DAOPHOT' mode]

Analyze photometric accuracy as f(dust/variable sky).Update imaging pipeline to work in variable sky

background conditions (i.e. |b| ~0.

Spectroscopy:Plan, obtain and process SEGUE plate pairs.

Analyze RV accuracy as f(S/N), stellar color/type. Update RV templates as needed to reach goals.[Do we have enough sky fibers? New ELODIE templates to insertzeropoints, N best fit (now 12)] Develop algorithms for [Fe/H], Teff, log g of stars

as f(S/N), stellar type. [Expanded Lick indicies,continuum-subtracted spectra in blue, smoothing,unskysubtracted-sky spectra availability] Incorporate algorithms into pipeline processing.

Quality Assurance:During observing 2004-2008,

monitor imaging and spectra data as they occur. Withinone month timescale for imaging (turn around for Target Selection),check tracking, photometric accuracy, S/N depth of images. Color magnitude diagrams. Search for 'special regions to scan'i.e. if a new 'great stream appears'.Spot check spectra of each type vs. S/N estimates and sciencerequirements.

Calibration/Standards: (IM) target and process 'PT' patches along SEGUE stripes for initial2% rms calibration (in time for Target Selection). scan crossing scans as needed to allow photometric ties ofSEGUE 'constant l' stripes to each other and to SDSS imaging. process crossing scan and other available photometric calib info.(SP) Obtain samples of stars with known Rvs, Metals, log g,spectral types to calibrate algorithms for parameter estimation.i.e. plates on Globular and Open Clusters of known RV, [Fe/H].Match to USNO-B2.0 or other catalogs of known info proper motions.

Databases/Data distribution/Documentation:

Support initial catalogs and value-added information as 'Flat Files' in SDSS 'DAS' format, with web sites

Design/Modify 'indexed-database' design to includenew parameters/information (data model changes).

Publish (in some form), TS algorithm, selectionfunction, goals and science background.

Science Analysis:

Stellar Atmosphere modeling and parameter estimation is still a bit of a 'black art', we need your experts and expertise. SEGUE has potentialto revolutionize this field!! Think Big!

Work on the key project or some of the other'57' science projects with initial sample (~20,000 SEGUEstars already available in Aug/Sep 04) with intentto determine feasibility of the science.

Papers:

Metals in Sag stream

Metals in Mono/Canis Major Stream

Spectra of everything selection function, stellar spectral atlas

SDSS DR2/DR3 selection function, target selection algorithm

Metalicity Distribution in the MW (DR2 and beyond)

The Lowest Metal Stars

Techinques for measures stellar atmosphere parameters in large sample of R~2000 SDSS spectra.

SEGUE Target Selection and early results.

We are 'new' to the rich fieldof stellar kinematicand population analysis, with implications for dark matter andgalaxy history studies on theGalaxy easiest to observe.

We need your help! [Meeting Oct 2]There are many opportunities tocontribute, including student projects.

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 as of September 30, 2004 Black= completed stripe or plate pair

WDA/BHBF TurnoffG III +VLow MetalsK IIIK VM VAGBCool Wds

SEGUE currently has 10 categories,(we have openings for G dwarf specialists)

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

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

Kinematic, Chemical populationstudies of the Milky Way and halo

White Dwarf Issues: ?

N=25

Cool White Dwarf CandidateIssues: Proper Motion > 30mas/yr

N=10

BHB Star, probe outer halo, streams to 150 kpcIssues: Are we getting essentially 'all' of these?

N=125

-400 -300 -200 -100 0 100 km/s

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

Issues: Do we need more faint Fs per plate for streams?What about P1 cut?

N=150

-400 -300 -200 -100 0 100 km/s

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

Issues: Giants vs. Dwarfs? Color band ok?

N=375

-400 -300 -200 -100 0 100 km/s

K Giants Issues: Color cuts ok, selection efficiency still low?

N=125

K Giant:Narrowerlines, featuresless deep.

K dwarfStrongerfeatures,broaderlines.

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

Issues: Faint cutoff?USNO Match? Disk Science ok?

N=125

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

Issues: Wish to weight much more towards bright g<18.5

N=150

M dwarfs

Issues: sub-dwarf alg, brown dwarf alg, PPM cut modify? How faint?

N=50

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

Issues: Efficiency, use only on Sag/Mon? color cuts?

N=10

Issues:

Exposure times for GC plates?

When will be ready to tackle Open Clusters?

Peregrine's cross scan on open clusters forthis Fall?

Redo Hyades, M67?

Globular Cluster Plates 1960-1962 (M15/M2)

Open Cluster Plates

M67, Hyades? RV standards, go down stellar locus

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.

WDA/BHBF TurnoffG III +VLow MetalsK IIIK VM VAGBCool Wds

Spectroscopic targets selected to probe variety of distances from the sunfrom < 1 kpc to > 100 kpc, basically through a 'standard candle' color cutto select stars representative of each distance.

Cool White Dwarf Candidate

-43 -37

-31 -25

1100S

Binned6x3deg

l =50 deg

at 4 b's.

Possiblestream present,but needto modelspheroid.

Photoincrowdedfieldsas we pass thru|b| = 0plane,will beimprovedin SEGUEoutyears.

SEGUE footprint as of Sep 30, 2004Black= completed stripe/plate

29/400 plates 7% done.

K Giants