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Star Formation Rates, Ages and Masses of Massive Galaxies in the FORS Deep and GOODS South fields

Explore galaxy assembly and evolution through luminosity functions, mass functions, and star formation rates derived from accurate photometric redshifts. Benefit from a wide sample covering ~10000 galaxies in the FORS Deep and GOODS South fields. Utilize broadband SEDs to estimate masses and compare FDF I-selected galaxies with GOODS K-selected ones to ensure accuracy. Investigate mass functions, morphologies, chemical abundances, and galaxy properties to enhance our understanding of galaxy evolution. Collaboration with observatories and use of advanced technology ensure thorough research outcomes and insights into galaxy formation and development.

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Star Formation Rates, Ages and Masses of Massive Galaxies in the FORS Deep and GOODS South fields

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  1. Star Formation Rates, Ages and Masses of Massive Galaxies in the FORS Deep and GOODS South fields R. Bender, A. Bauer, N. Drory, G. Feulner, A. Gabasch, U. Hopp, M. Pannella, R.P. Saglia, M. Salvato (Universitäts-Sternwarte München, Max-Planck Institut für Extraterrestrische Physik, University of Texas) Map out galaxy assembly: Luminosity functions Stellar mass functions, Star formation rates as a function of mass.

  2. Star Formation Rates, Ages and Masses of Massive Galaxies in the FORS Deep and GOODS South fields • Study evolution of galaxies with broadband deep U to K surveys. • LFs, Mass Functions, SFRs do not require spectroscopy but can • be derived with accurate photometric redshifts. • Advantage of photo z: no color selection bias, fainter luminosities, • larger sample (~10000 galaxies in FDF and GOODS S sub-sample) • FORS Deep Field (IAB=26.8): 98% of all galaxies with dz/(1+z)<0.03; • GOODS S (KAB=25.4): dz/(1+z)<0.055 • Deep I-selection misses only a small fraction of deep K selected • objects. Surveys to IAB=27 also cover a large fraction of submm gals. • Derive masses from broadband SEDs by fitting exponential SFH + • bursts (with extinction); exp. SFHs only do NOT work for large • l-range (check via comparison with local SDSS+2MASS sample). • Further check: compare FDF I-selected with GOODS K-selected.

  3. The FORS Deep Field (FDF, GTO project) • FDF goals: evolution of galaxies: their luminosity functions, star formation rates, morphologies, chemical abundances, dark halo properties, Tully-Fisher , FP relations etc... • Imaging in U,B,g,R,I,z,J,K (to AB ~ 27 in optical). • Depths within 0.5 ... 1 mag of Hubble Deep Fields. • Area ~5 times HDFs together (6.8‘ x 6.8‘). • 8000 objects with photometric z and type. • Spectroscopy available for ~360 galaxies. • HST Advanced Camera observations obtained. • FORS partners: Observatories in Heidelberg, Göttingen and Munich built two FORS spectrographs for the VLT. • FDF science team: Appenzeller, Bender, Böhm, Drory, Gabasch, Heidt, Hopp, Mehlert, Noll, Saglia, Seitz, Ziegler et al.

  4. FDF field selection: DSS image QSO 0103-260 z=3.36 FDF Criteria: z>3 QSO in field, minimize foreground of stars and (z<0.2) galaxies, high Galactic latitude, good accessibility from VLT

  5. FORS Deep Field FDF BRI real color image FWHM = 0.45” QSO 0103-260 z=3.36

  6. ~1’x1’ enlargements

  7. HST ACS FDF BRI ~1’x1’ enlargements

  8. K-band (26.3) selection (FIRES) vs I-band (26.8) selection (FDF) FIRES only FDF as well

  9. The Goods-South Field • J, H, K VLT images, 50 arcmin2, (8 tiles), seeing 0.4-0.5” • K-selected catalog: 3297 galaxies to KAB=25.4 • U, I: GOODS/EIS public survey • B, V, R: Garching/ Bonn deep survey Salvato et al. 2006, A&A, submitted K-band 2.5’x2.5’

  10. Global galaxy parameters from photometric redshifts • Advantages: • - large samples of ‘normal’ galaxies • - redshifts for faint objects • - full spectral energy distribution • - ‘cheap’ in telescope time • - modest amount of spectroscopy • needed to test reliability • Potential problems: • - accurate photometry needed • - calibrating galaxies are bright • - larger errors in redshift • - catastrophic failures in z

  11. Observed vs. synthetic color-color diagrams of stars used to check photometric calibration

  12. Semi-empirical SEDsderived from broad-band fluxes of galaxies with spectroscopic z by fitting them with SEDs of Bruzual&Charlot, Maraston and spectra from FDF, Kinney&Calzetti, Manucci => used as templates to determine photometric redshifts

  13. Examples of template fits to FDF broad band photometry I

  14. Examples of template fits to FDF broad band photometry II

  15. check: photo z vs. spec z 180 galaxies used to derive semi- empirical SEDs 180 galaxies in the control sample QSO Only ~ 1% catastrophic failures on normal galaxies! (mostly very blue, faint dwarf objects with almost power-law SEDs)

  16. check: photo z vs. spec z for MB > -20 Photometric z for faint objects: o.k.!!

  17. FDF: distributions of photometric redshift errors and c2

  18. FDF redshift distribution: extends to z ~ 6 (similar to HDFs) another check: peaks in photometric z distribution well consistent with peaks in spectroscopic z distribution at: 0.22, 0.33, 0.39, 0.45, 0.77, 2.35, 3.38 (QSO)

  19. MB distribution in FDF vs z completeness limits in FDF: red massive galaxies to z ~ 2 blue star- forming galaxies to z ~ 6 Most luminous galaxies in optical bands tend to have oldest SEDs clustering in redshift space very obvious! Ho = 70 km s-1 Mpc-1 Wm= 0.3, WL = 0.7

  20. Type classification: Sersic n vs. T vs. SED Type

  21. Type dependent angular clustering at 0.2 < zphot< 0.4 all types

  22. irregulars

  23. early types

  24. ellipticals

  25. Estimating Schechter parameters F*, M*, a: parameter coupling in luminosity function fits V/Vmax and completeness corrections applied

  26. The LF faint end slope ain the FDF:

  27. FDF constraints on aand M*between z ~ 0.6 (low M*) and z ~ 3.5 (high M*) (some low z bins have large errors because scaling with c2 was applied) 2800 A 1500 A z g’ u’

  28. What about Steidel et al. 1999: a ~ –1.6 ? (galaxies selected by drop outtechnique) FDF Steidel et al. 1999 FDF The faint end slope at 1700A: z~3 z~4.1

  29. FDF FDF Steidel et al. 1999 FDF: z ~ 3 z ~ 4 • cannot be settled definitely yet, but a~ –1.6 pretty unlikely

  30. Measured faint end slopes of the LFs in FDF: adopted in the following:

  31. Evolution of LF in g’ band: z = 0.3 to z = 5.5

  32. Evolution of LF at 2800 A: z = 0.3 to z = 5.5

  33. 1500 A 2800 A F* vs. M* for z = 0.6 to z = 4.5 u’ g’

  34. Evolution of M* and F* for fixed a Fits based on FDF alone predict SDSS values reasonably well.

  35. same B-band evolution as observed for bright cluster ellipticals: DB ~ z provides SF history consistent with Madau diagram a and b values for 1500 A and 2800 A imply SFR ~ constant

  36. The UV-luminosity density and SFR For the FDF, the extrapolation to L=0 in the calculation of Ltot amounts to only 2%-20%, depending on redshift. (no correction for dust)

  37. Adelberger & Steidel (2000) dust corrected • Evolution • of Star • Formation • Rate • Cosmic variance • between FDF and • GOODS <0.1dex • Luminous galaxies • immune to wave- • length dependent • selection effects. • Luminous galaxies • (B- to K-selected, • L>L*) contribute • only ~1/3 to total • star formation rate • at all redshifts. • Gabasch et al. 2004b, • ApJ Lett. in press a= -1.6 a= -1.1 GALEX

  38. Broadband galaxy masses from SED-fits: I. check by application to combined SDSS+2MASS data set (exp.SFH+bursts) Drory, Bender, & Hopp, ApJL, 616, 103

  39. … and by comparison with masses from spectral analysis of SDSS data by Kauffmann et al. (2003) (17000 obj.): o.k.! Kauffmann + 2003 SDSS spectral feature mass Mass from SED fitting Drory + 2004

  40. Residuals of photometric and spectroscopic masses against a dynamical mass indicator: o.k.!

  41. Evolution of the galaxy mass function at low z: MUNICS (photo z) and K20 (mostly spectra)

  42. Stellar masses of galaxies in FDF and GOODS S: red=old blue=young at all z, massive galaxies are older than low mass objects! Drory et al. 2005, ApJL, 619, 131

  43. Evolution of the galaxy stellar mass function with redshift: Drory et al. 2005, ApJL, 619, 131 See poster by Pannella et al. for MF as function of morphology

  44. Evolution of total stellar mass density. Drory et al. 2005, ApJL, 619, 131

  45. Number density evolution of massive galaxies. Drory et al. 2005, ApJL, 619, 131

  46. Specific star formation rates (from [OII]) to z ~ 1.5: Bauer et al. 2005, ApJL, 621, 89 Bauer et al. 2006 Study star formation as a function of mass and redshift.

  47. Specific star formation rates (from UV cont.) z ~ 4.5: Feulner et al. 2005, ApJL, 633, 9 Study star formation as a function of mass and redshift: strong constraints on models of galaxy formation.

  48. Specific star formation rates (from UV cont.) z ~ 4.5: • More massive galaxies • form their stars earlier. • Stars are formed by z~2 • More massive galaxies • show a steeper decline • in SSFR.

  49. Summary: • faint end slope of luminosity function is shallow at high z • LF evolution stronger at shorter wavelength • F* decreases, L* increases with redshift in all bands • analysis of cosmic SFH not very sensitive to l-selection • at all z, L>L* galaxies contribute ~1/3 to total SFR, but less to SSFR • at all z, massive galaxies are older than low mass galaxies • high mass galaxies form their stars earlier and faster • Papers: FDF+GOODS LFs, SFH: Gabasch et al. 2004, 2005 • FDF+GOODS+MUNICS+SDSS+2MASS masses: • Drory et al. 2001, 2003, 2004, 2005

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