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GEMS: The Evolution of Disc Galaxies: 

GEMS: The Evolution of Disc Galaxies Marco Barden

Galaxy Evolution: 

Galaxy Evolution Archaeology  Look-back approach Galaxy evolution  Population evolution Important because: Even in local universe 60-80% discs Most of all stars form in discs Most of the stars of the MW formed since z~1  measure structural parameters of discs as a function of time

Theoretical Models: 

Theoretical Models Expectation from models (e.g. Mo, Mao, White 1998, Bouwens andamp; Silk 2002): Discs in the early universe were more compact were on average brighter had higher surface brightness had lower stellar masses than disc galaxies today  large redshift surveys to constrain models

Observations: 

Observations Several surveys (e.g. CFRS, DEEP, GOODS)  controversy Strong SB evolution (result of higher overall SFR, Schade et al. 1996) No evolution in SB (selection effects, Simard et al. 1999) At z~1 a new class of high SB galaxies (0,eandlt;17.7 mag arcsec-2) appears (Simard et al. 1999) Ravindranath et al. 2004

Observations: 

Observations Restricted luminosity range  interpretation Surface brightness dimming  selection effects dominate a high-z Objects are small  high spatial resolution needed Distribution of surface brightness is wide  large samples

GEMS: Galaxy Evolution from Morphology and SEDs: 

GEMS: Galaxy Evolution from Morphology and SEDs MPIA: Barden, Bell, Borch, Häußler, Heymans, Meisenheimer, Rix (P.I.) STScI: Beckwith, Caldwell, Jogee, Somerville AIP: Jahnke, Sanchez, Wisotzki Oxford: Wolf UMass: McIntosh U. Arizona: Peng

GEMS: Galaxy Evolution from Morphology and SEDs: 

GEMS: Galaxy Evolution from Morphology and SEDs E-CDFS Largest HST colour mosaic: ~30’x30’, 9x9 ACS tiles, ~150 HDF 125 (GEMS) + 50 (GOODS) orbits 2 filters: F606W (mABandlt;28.3) F850LP (mABandlt;27.1)

GEMS: Galaxy Evolution from Morphology and SEDs: 

GEMS: Galaxy Evolution from Morphology and SEDs ~10000 redshifts from COMBO-17 (Wolf, Meisen-heimer et al. 2003) 5 broad / 12 medium band filters z~0.02, 0.1andlt;zandlt;1.3, mrandlt;24 SEDs (3500-9250Å)

The Disc Sample: 

The Disc Sample Sersic fits to F850LP images with GALFIT (Peng et al. 2002) Selection of discs with nandlt;2.5 Completeness  simulations (Häußler et al. 2004) Size correction (de Jong 1996)

Completeness & Selection Effects: 

Completeness andamp; Selection Effects

The Magnitude-Size Relation: 

The Magnitude-Size Relation

The Magnitude-Size Relation: 

The Magnitude-Size Relation

The Magnitude-Size Relation: 

The Magnitude-Size Relation HDF FIRES Trujillo et al. 2004

The Magnitude-Size Relation: 

The Magnitude-Size Relation V(z)=(21.240.08) - (1.790.11) z

The Magnitude-Size Relation: 

The Magnitude-Size Relation Bouwens andamp; Silk 2002

The Mass-Size Relation: 

The Mass-Size Relation

The Mass-Size Relation: 

The Mass-Size Relation

The Mass-Size Relation: 

The Mass-Size Relation

Conclusions: 

Conclusions The magnitude-size relation of disc galaxies changes as a function of redshift  average SB increases The appearance of high SB galaxies at high-z is a result of the increasing average SB Disc galaxies at different redshifts follow the same mass-size relation  galaxies form inside-out Mass densities stay roughly constant with redshift

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