“Artists can color the sky red because they know it’s blue. Those of us who aren’t artists must color things the way they are or people might think we’re stupid.” Jules Feiffer

Red Galaxies at High Redshift Stijn Wuyts, Marijn Franx, Pieter van Dokkum, Ivo Labbé, Natascha Förster Schreiber, Greg Rudnick, TJ Cox, Phil Hopkins, Brant Robertson, Lars Hernquist When did the stars in galaxies form? How was the mass in galaxies assembled?

When did the stars in galaxies form? How was the mass in galaxies assembled? Ingredients & HistoryFrom colors to physicsEvolution

Telescopes

Galaxy interactions

-simulations-

Galaxy interactions -simulations- Holmberg 1941

Galaxy interactions -simulations- Holmberg 1941 Springel et al.

Quasars & Black Holes

Richards et al Quasars & Black Holes Schmidt dF-SDSS LRG and QSO Survey

Genzel et al. Quasars & Black Holes Schmidt 1963 Häring & Rix 2004

Normal galaxies Hubble 1926 Hubble 1936 HDFS (5 arcmin 2 ) MS (25 arcmin 2 ) CDFS (113 arcmin 2 ) Labbé et al. 2003

Normal galaxies Hubble 1926 Hubble 1936 HDFS (5 arcmin 2 ) MS (25 arcmin 2 ) CDFS (113 arcmin 2 )

Stellar population synthesis Wood 1966

Evolutionary stellar population synthesis Bruzual & Charlot 2003

Evolutionary stellar population synthesis Star formation history SSP, exponentially declining (τ300), CSF

Evolutionary stellar population synthesis Dust screen (Calzetti et al. 2000)

SED modeling - results Red galaxies at high redshift do not form a uniform population.

Red galaxies at high redshift dominate at the high mass end. SED modeling - results

Red galaxies dominate the total IR emission at high redshift. SED modeling - results

Testing SED modeling with simulations

Wide range of spectral types Have real universe equivalents Testing SED modeling with simulations

Mismatch real vs. template SFH → Impossible to correct for difference light- vs. mass-weighted Impact of star formation history

Impact of dust Increased extinction towards young stellar regions reduces offset light- vs. mass-weighted properties.

Mismatch real vs. template SFH → Impossible to correct for difference light- vs. mass-weighted → Less severe in the presence of age-dependent extinction Impact of dust IntrinsicAttenuated

Every observer is limited by the light he/she receives. Impact of dust Effective reddening Effective extinction

Input: Calzetti, MW or SMC reddening curve Effective reddening: greyer than Calzetti Impact of dust

Modeling sub-solar stellar populations with solar-metallicity templates. → underestimate reddening → underestimate extinction Impact of metallicity

Real: Stars + AGN → Recovered: younger & dustier stellar pop. Impact of AGN

Testing SED modeling with simulations: results

An evolutionary scenario Sanders et al ULIRG (L > L sun ) QSO

An evolutionary scenario Hopkins et al. 2006

Quasar to galaxy demographics Hopkins et al. 2006

Quasar to galaxy demographics Hopkins et al. 2006

Abundance of massive galaxies

Mass function

Colors of massive galaxies V-J U-V

Colors of massive galaxies – by type

Selecting by specific star formation rate

Abundance of massive galaxies – by type

Pair statistics

Red Galaxies at High Redshift Observations Diversity at high redshift Evolutionary scenario involving merger-triggered QSOs Abundance of massive galaxies OK Colors of dusty red galaxies not reproduced Conclusions

Emlen 1967, 1970 After man, the indigo bunting is the best documented example of a species that in its earthly life uses celestial bodies outside the solar system.

When did the stars in galaxies form? How was the mass in galaxies assembled? Ingredients & HistoryFrom colors to physicsEvolution