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The cosmic star formation rate from the FDF and the Goods-S Fields

The cosmic star formation rate from the FDF and the Goods-S Fields. R.P. Saglia – MPE reporting work of/with R. Bender, N. Drory, G. Feulner, A. Gabasch, U. Hopp, M. Pannella, M. Salvato. Introduction The Fors Deep and Goods-S Fields Luminosity functions

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The cosmic star formation rate from the FDF and the Goods-S Fields

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  1. The cosmic star formation rate from the FDF and the Goods-S Fields R.P. Saglia – MPE reporting work of/with R. Bender, N. Drory, G. Feulner, A. Gabasch, U. Hopp, M. Pannella, M. Salvato • Introduction • The Fors Deep and Goods-S Fields • Luminosity functions • Star Formation Rates and stellar densities (up to z=5) • Morphologies (up to z=1) • Conclusions Gabasch et al. 2004, A&A, 421, 41; Drory et al. 2005, ApJL; 619, L131; Gabasch et al. 2004, ApJL, 616, L83; Pannella et al. 2005, ApJL, in prep Renzini Ringberg 2005

  2. Introduction “Madau plot”: Star Formation Rate history of the Universe Bouwens et al. 2004 • Open questions: • Cosmic variance • Galaxy selection • Faint-end contribution • Role of Dust • Morphology split Hernquist & Springel 2003 Renzini Ringberg 2005

  3. The FDF and Goods-S fields U…K photometry, >7 times larger field than HDF Heidt et al. 2003, A&A, 398, 49 Salvato et al. 2005, in prep Renzini Ringberg 2005

  4. Photometric redshifts SED template fitting Bender et al. 2005 Gabasch et al. 2004, A&A, 421, 41 362 spectra Renzini Ringberg 2005

  5. Luminosity Functionsat 1500 Good agreement with previous LF down to the mag limit. a = -1.07+-0.04 a = -1.6 excluded at 2s level z=0.6 z=1.3 Gabasch et al. 2004, A&A, 421, 41 z=2.5 z=4.5 Renzini Ringberg 2005

  6. Evolution of the LFs Steidel et al. 1999 Renzini Ringberg 2005

  7. The UV-luminosity density and SFR Theextrapolation to L=0 amounts to 2-20% for the FDF magnitude limits! (no correction for dust) Renzini Ringberg 2005

  8. Adelberger & Steidel 2000 The SFR in the FDF Factor 5-9 correction Dust At z>3 B drop-outs 0 2 4 6 0 2 4 6 • No difference with I or B catalogues Gabasch et al. 2004, ApJL 616, L83 Renzini Ringberg 2005

  9. The SFR in FDF and GOODS-S Renzini Ringberg 2005

  10. Photoz + BC03 • 2 components • (main+burst) • Age, metallicity • Dust, component ratio • Errors in log M/L: • 0.1<d log M/L<0.2 Stellar masses Renzini Ringberg 2005

  11. SPITZER Egami et al. 2004 ApJS 154, 130 GALEX Schiminovich et al. 2005, ApJL 619, L47 Dust and SFR • GALEX confirms • SFR at z<1 • SPITZER shows that • ULIRG cannot dominate Stellar mass Factor 2.5-3 Renzini Ringberg 2005

  12. Morphologies Analysis of HST ACS images: FDF: 4 pointings, 1 orbit per pointing in the F814W filter 40 minutes exposures, I(AB, 10 sigma) = 26 Goods-S: 3/2.5/2.5/5 orbits in the BViz filters 100/80/80/160 minutes exposures BViz(AB, 10 sigma) = 27/27.2/26.5/26.5 Visual Classification performed by U. Hopp Quantitative morphology performed by M. Pannella, fitting the 2D images with PSF convolved with the Gim2D and Galfit packages, I=24/24.5 for FDF (F814W) and Goods (F775W), z<1.15 Sersic Profiles Renzini Ringberg 2005

  13. Quality Control Mock catalogue of 4000 objects for each of the two fields, with 22.5<I(AB)<Ilim 0.05”<Re<2” 0.5<n<6 0<ellipticity<0.7 Renzini Ringberg 2005

  14. Visual Morphology Final catalogue with 1647 objects, 90 sq. arcmin area, z<1.15, with Masses, redshifts, luminosities, dimensions, profiles Renzini Ringberg 2005

  15. At any redshift objects with the highest M/L ratio are cut out of the sample because of the flux limit. Mass completeness • SSP from BC03 • formation at z=10 • no dust • sub-solar metallicity • passively aging • Largest M/L • lowest detectable M Renzini Ringberg 2005

  16. Morphological stellar mass functions The mass at which disks becomes dominant is increasing with z Disks dominate at all redshifts the low mass end of the MF In good agreement with Bundy et al. (2005) at the same z and Bell et al. (2003) at z=0 “Morphological Downsizing” ? Renzini Ringberg 2005

  17. Stellar mass density evolution The total mass density at z=1 is 50% lower than at z=0 The morphological mix evolves dramatically with redshift Mass density moves from disks to bulges from z=1 to z=0 In agreement with Bundy et al. 2005, Brinchmann & Ellis 2000 Renzini Ringberg 2005

  18. Two scenarios Option 1: the 50% “missing stellar mass” at the high mass is provided by in situ star formation. The morphological mass density evolution from disks to bulges is driven by secular evolution. Option 2:The star formation rate is not high enough to explain the missing stellar mass. Merging of (smaller mass) galaxies must play a key role. Merging of the massive disk systems explains the morphological evolution. Renzini Ringberg 2005

  19. Specific star formation rates Only 2 objects would be able to double their masses to z=0 assuming constant SFR Almost all the sample would be unable to increase its original mass by more than 30% with constant SFR in situ  Option 2 favoured Renzini Ringberg 2005

  20. Conclusions: the SFR • SFR estimates from B, I and I+B catalogues agree well and are • confirmed by GALEX at z<1 • SFR estimate from K catalogue is lower by 0.3 dex • because it is missing galaxies with L<L* • Cosmic variance < 0.1 dex • Bright galaxies with L>L* produce 1/3 of the total SFR • Previous estimates of the SFR are too high by a factor of 2 • because the faint-end slope of the LF has been overestimated • Dust correction is ~ factor 3 • Complete census of galaxies nearly reached: SPITZER • The SFR is roughly constant up to z=4 and declines slowly beyond Renzini Ringberg 2005

  21. Conclusions: Morphologies • The morphological mix evolves strongly with redshift • The stellar mass density moves from disks (at z=1) to • bulges (at z=0) • Merging must have an important role Renzini Ringberg 2005

  22. The dust correction Using a factor 6.5 dust correction (or A28000=2): Renzini Ringberg 2005

  23. The Sersic profile Renzini Ringberg 2005

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