Evolution of Rest-frame Luminosity Density to z=2 in the GOODS-S Field Tomas Dahlen, Bahram Mobasher, Rachel Somerville, Lexi Moustakas Mark Dickinson, Harry Ferguson, Mauro Giavalisco and the GOODS Team GOODS-S multi-waveband observations Photometric redshifts Results on LFs and luminosity densities Summary ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher

Two sets of data covering GOODS-S WFI R-selected ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher CTIO-U, WFI-BVRI, FORS-RI, ISAAC JHKs, SOFI JHKs psf: 0.9 arcsec Area: 1100 sq. arcmin Redshift range: 0.1<z<1.0 R AB < 24.5 Number of galaxies: Rest-frame U and B to z=1 ISAAC Ks-selected ACS BViz, ISAAC JHKs psf: 0.45 arcsec Area: 130 sq arcmin Redshift range 0.1<z<2.0 Ks AB <23.2 Number of galaxies: 2768 Rest-frame J to z=1 and B to z=2 ISAAC now twice as large

GOODS Phot-z Code  six templates used  Luminosity function used as prior  Cosmic opacity from Madau et al.  Extinction allowed as a free parameter, estimating E(B-V) for each galaxy  Interpolates the spectral types  Easily extended to other bands (ie IRAC, GALEX etc)

Luminosity functions are calculated using * 1/Vmax method * Maximum likelihood method Traditionally (ideally): each galaxy has one redshift -> one absolute magnitude -> one galaxy added to magnitude bin in LF Using phot-z's: Phot-z's have relatively large errors Each galaxy is represented by a redshift distribution

Photometric Redshifts Template fitting method Input LF prior Extinction correction Comparison with ~400 spec-z's: ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher Accuracy:  z)/(1+z spec ) = 0.12 Accuracy.  z)/(1+z spec ) = 0.06, after excluding 3% out-liers

Photometric Redshifts & the Luminosity Function ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher  (M)dM =   V i (M i ) We use the 1/V max -method to calculate the LF: Uncertainties in phot-z may introduce bias when determining the LF (Chen et al. 2003) Instead of a single redshift, we use a probability distribution for each object derived from phot-z method.  (M)dM =  P i /V i (M i ) The 1/V max -method is now expressed as:

Results: The Luminosity Function, 0.1<z<0.5 ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher 'Quasi-local' B-band LF for different types Late-types follow composite LF Early-types have Gaussian shape Starbursts are fainter Ho=70 km/s/Mpc,  M =0.3,   =0.7

Results: The Luminosity Function, 0.1<z<0.5 ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher 'Quasi-local' U-band LF for different types Similar to B-band but Starbursts more dominating

Results: The Luminosity Function, 0.1<z<0.5 ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher 'Quasi-local' J-band LF for different types Steep faint-end slope (as optical) Starbursts less abundant BandM*   * U B J

Results: The Luminosity Function, 0.1<z<1.0 ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher U-band B-band J-band

Results: The Luminosity Function, 0.1<z<1.0 ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher No strong evolution in faint-end slope in U, B or J Brightning of M* in U and B to z~1 (  M~0.5 mag) Slight fading of M* in J to z~1 Faint-end slope  ~ , in all bands U&B slopes consistent with e.g., COMBO-17, FORS Deep Field J-band consistent with local 2MASS K-band slope  =-1.09? Yes!

Results: Luminosity density evolution ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher The LF is integrated to derive luminosity density   =  (2+  )  *L* (for Schecheter function approximation) Mean increase in all bands Largest evolution in U-band Relative contribution to  from different spectral types: Significant increase of Starburst contribution with z Highest fraction Starburst in U-band Decrease of Early-type fraction with z Lowest Early-type fraction in U-band

B-band luminosity density evolution to z=2 ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher R- and K-selected measurements consistent where they overlap Increase by factor ~1.7 in  B to z=1 (compared to local value), Increase consistent with e.g., COMBO-17 No significant evolution at z>0.6 (in any survey)

Conclusions ”Massive Galaxies”, STScI, 27 Sept 2004 Bahram Mobasher Important to incorporate phot-z errors when deriving the LF No significant evolution in the shape (  ) of the LF to z=1 in U,B, and J Brigthening of M* in optical bands (U, B) with redshift Indication of fading M* with redshift in J Faint-end slope  ~ to z~1 Different shape of type-specific LFs (Early-types, Late-types and Starbursts) Increase in U-band luminosity density to z=1 (less significant in B and J) Sharp increase of the relative contribution from Starbursts in the luminosity density to z=1, especially in U, along with a decrease in the Early-type contribution The B-band luminosity density increases by a factor ~1.7 to z~1. No significant evolution in the B-band luminosity density at z > 0.6