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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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2 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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3 What Data do we Need ? (to tackle this via “look-back” observations) Galaxy properties as a function of: –Redshift/Epoch with t/t H ~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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4 Survey Requirements Several 10,000 galaxies with –Redshifts to z>1 (good to a few percent) –Faint flux limit m r ~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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5 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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6 CFRS Luminosity Function
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7 Status quo: Morphologies
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8 Status quo: bars
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9 Status quo: Bulge-Disk Fitting: GIM2D (Simard etal 1999) Data: somewhat heterogeneous HST imaging
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11 Status quo: disk sizes
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12 Status quo: Disk size function Lilly et al 1998 HST images of CFRS galaxies
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13 Status quo: merger rate
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14 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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15 GEMS: Key to “internal structure” ( G alaxy E volution from Morphology and S EDs) 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: m z ~27.5
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16 GEMS 58 1.5% of total
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17 COMBO-17 (~0.7”) vs. HST/ACS
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18..and we do have the redshifts.. ~1.2´x 2.2´ (0.003 of the total field)
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19 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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20 GEMS Analysis: Basic Steps Task ResponsibleDate 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 CodePeng Häußler,Jogee ~95% D GIM2DMcIntosh~95% D
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21 Task ahead: Fitting 30,000 galaxies
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22 GEMS vs past work 30-fold number increase Well defined sample with ample external information z-band ACS imaging
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23 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 experience BUT..... GEMS data instantly public With DEEP and VMOS, the COMBO-17 data will loose their uniqueness within a year
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24 Top-Level Science Goals How did stellar disks evolve/grow? –(Disk) size function –L vs r eff, Tully-Fisher Evolution of bulges/ellipticals –B/D ratios, growth of „old“ pops. –L vs r eff, fundamental plane Evolution of merger rate vs star burst rate Did „internal evolution“ play a role? –Bar statistics When are galaxies AGNs? –Host galaxies
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What do we want to accomplish? Get to know each other Take stock of our status quo –Data, software (tools), responsibilities Better define data products Prioritize science goals –Define approach –Clarify responsibilities –(Re-)define schedule –set of possible 1.generation papers GEMS vs. Other current activities
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27 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
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