GEMS Collaboration Meeting Baltimore, Jan 20-21, 2003
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GEMS Collaboration Meeting Baltimore, Jan 20-21, 2003 What do we want to accomplish? Get to know each other Take stock of our status quo –Data, software (tools),goals,... Better define data products Prioritize science goals –Define approach –Clarify team responsibilities –(Re-)define schedule GEMS vs. Other current activities
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GEMS Collaboration Meeting Baltimore, Jan 20-21, 2003. What do we want to accomplish? Get to know each other Take stock of our status quo Data, software (tools),goals,... Better define data products Prioritize science goals Define approach Clarify team responsibilities - PowerPoint PPT Presentation
Transcript of GEMS Collaboration Meeting Baltimore, Jan 20-21, 2003
GEMS Collaboration Meeting
Baltimore, Jan 20-21, 2003
What do we want to accomplish?
Get to know each otherTake stock of our status quo
–Data, software (tools),goals,...
Better define data productsPrioritize science goals
–Define approach–Clarify team responsibilities–(Re-)define schedule
GEMS vs. Other current activities
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Galaxy Population over the last 10 Gyrs
How many stars have formed since z~1.2 ?
– In which Galaxies? – Mostly during in star-bursts, or “quiescently”?– Which galaxies are “old” already?
How did the clustering of galaxies evolve ?– Mass clustering vs. galaxy bias.– Always a morphology-density relation?
When and how did bulges and disks form ?– How did the merger rate evolve?– Is there an „angular momentum“ problem– Do disks grow inside out?
What makes AGNs light up?– Dramatic drop in AGN lum. density since z~1
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What Data do we Need ?(to tackle this via “look-back” observations)
Galaxy properties as a function of:– Redshift/Epoch with t/tH ~1
Note: z=1.2 t look-back = 10 Gyrs
– Luminosity– Spectral Energy Distribution (SED)– Internal structure (size, bulge-to-disk, etc.)– Environment a multi-dimensional parameter space
+ account for large-scale fluctuation in the galaxy and mass distribution.
+ include “typical” galaxies at all epochs i.e. reach below L* at all redshifts
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Survey Requirements
Several 10,000 galaxies with– Redshifts to z>1 (good to a few
percent)
– Faint flux limit mr~24
– SEDs, including (rest-) UV and optical
Several large fields– Co-moving size > 5 Mpc
High-resolution (0.1”) imaging– typical scale lengths are 0.3 asec– two-color rest-frame B at all z
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Existing Faint Surveys
CFRS – Lilly, LeFevre, et al. – I<22.5, 591 galaxies
CNOC2– Yee, Carlberg etal.– R<21.5, z<0.55,2000 galaxies
HDF– Williams etal., Cohen etal. – redshifts for 200 objects
Medium Deep Survey – Keck spectroscopy
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CFRS Luminosity Function
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Status quo: Morphologies
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Status quo: bars
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Status quo: Bulge-Disk Fitting:GIM2D(Simard etal 1999)
Data:
somewhat heterogeneous HST imaging
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Status quo: disk sizes
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Status quo: Disk size functionLilly et al 1998 HST images of CFRS galaxies
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Status quo: merger rate
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Surveys at Hand
COMBO-17 C. Wolf, K. Meisenheimer (co-PIs), E. Bell, C.
Maier, H.-W. Rix, S. Phleps, A. Borch + Edinburgh, Bonn
– Data from WFI at the MPG/ESO 2.2m on La Silla
GEMS – 2-color, deep HST/ACS mosaic ( ~180 x HDF
area)
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GEMS: Key to “internal structure”(Galaxy Evolution from Morphology and SEDs)
Large HST program (125+50 orbits) to image “extended-Chandra-Deep-Field-South”
– 10,000 redshifts from COMBO-17– 9x9 ACS tiles 150 x HDF– V and z
– Limit: mz~27.5
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GEMS 58
1.5% of total
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COMBO-17 (~0.7”) vs. HST/ACS
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..and we do have the redshifts..
~1.2´x 2.2´ (0.003 of the total field)
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GEMS: Top-Level Project Steps
Image acquisision, reduction Object Detection+Match-up
Fitting/Morphology quantification
Selection/fitting simulation Structural „master catalog“
Empirical results Link to theoretical predictions Model-dependent results
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GEMS Analysis: Basic Steps
Task Responsible Date
Complete (%)
Data Acquistion
Caldwell, Vick, Peng
100% P ~95% E
Tile Reduction
Caldwell ~90% D~50% E
Object Detection
McIntosh ~90% D ~20% E
Galfit Code Peng Häußler,Jogee
~95% D
GIM2D McIntosh ~95% D
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Task ahead: Fitting 30,000 galaxies
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GEMS vs past work
30-fold number increase Well defined sample with ample
external information z-band ACS imaging
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Our competitive edge
COMBO-17 full catalog not yet published
GEMS mosaic largest HST image mosaic of sufficient depth (perhaps for a while...)
Comprehensive team experienceBUT..... GEMS data instantly public With DEEP and VMOS, the COMBO-17
data will loose their uniqueness within a year
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Top-Level Science Goals
How did stellar disks evolve/grow?– (Disk) size function
– L vs reff , Tully-Fisher
Evolution of bulges/ellipticals– B/D ratios, growth of „old“ pops.
– L vs reff , fundamental plane
Evolution of merger rate vs star burst rate
Did „internal evolution“ play a role?– Bar statistics
When are galaxies AGNs?– Host galaxies
What do we want to accomplish?
Get to know each otherTake stock of our status quo
–Data, software (tools), responsibilities
Better define data productsPrioritize science goals
–Define approach–Clarify responsibilities–(Re-)define schedule–set of possible 1.generation papers
GEMS vs. Other current activities
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Spectroscopy goals for COMBO-17/GEMS
Redshifts – outliers?– present median precision 180 Mpc– GEMS image contains 6 x more galaxies with
good photometry Spectral features
– Balmer emission/absorption lines– AGN vs. star-formation diagnostics
Kinematics– Stellar and emission lines
(stellar) masses from SEDs, spectra and kinematics
Star-formation rates and metallicity
Interaction rates – local velocity dispersion
