A red sequence of massive field galaxies at z~2.3

Transcription

1 A red sequence of massive field galaxies at z~2.3 Mariska Kriek Princeton Galaxies In Real Life and Simulations Lorentz Center Leiden, September

2 When does the red sequence emerge? Identification of galaxies with quiescent populations beyond z=2 Talks Williams, Labbe, & Cimatti (e.g., Franx et al. 2003, Labbe et al. 2005, Daddi et al. 2005, Kriek et al. 2006, Cimatti 2008)

3 Kriek et al. 2006

4 Stellar populations in galaxies at z~2.3 2 independent diagnostics for stellar populations Stellar continua modeling Kriek et al. 2006

5 Stellar populations in galaxies at z~2.3 2 independent diagnostics for stellar populations red sequence? Stellar continua modeling Kriek et al. 2006

6 Is the red sequence already in place beyond z=2? Identification of galaxies with quiescent populations beyond z=2 Talks Williams, Labbe, & Cimatti (e.g., Franx et al. 2003, Labbe et al. 2005, Daddi et al. 2005, Kriek et al. 2006, Cimatti 2008) Several studies show that the red sequence disappears at z>1.5 (e.g., Conselice et al. 2005, Cirasuolo et al. 2008)

7 The disappearance of the red sequence at z>1.5? Cirasuolo et al. 2008

8 The disappearance of the red sequence at z>2.0? Williams et al. 2008

9 Is the red sequence already in place beyond z=2? Identification of galaxies with quiescent populations beyond z=2 Talks Williams, Labbe, & Cimatti (e.g., Franx et al. 2003, Labbe et al. 2005, Daddi et al. 2005, Kriek et al. 2006, Cimatti 2008) Several studies show that the red sequence disappears at z> (e.g., Conselice et al. 2005, Cirasuolo et al. 2008) Contradiction?

10 Is it possible to recover a red sequence with only broadband photometry? Kriek et al. 2008a

11 Is it possible to recover a red sequence with only broadband photometry?

12 Is it possible to recover a red sequence with only broadband photometry? Need spectroscopic survey of unbiased massive galaxy sample

13 A Red Sequence at z~2.3? Kriek et al. 2008b

14 A Red Sequence at z~2.3? Kriek et al. 2008b

15 Red-sequence galaxies at z~2.3 average best-fit model average spectrum 2 Gyr SSP Kriek et al. 2008b

16 Red-sequence galaxies at z~2.3 average best-fit model average spectrum 2 Gyr SSP Post-starburst spectral shape: red sequence just starting to build up? Kriek et al. 2008b

17 Comparison massive galaxies z~2.5 and z~3.5 3 galaxies in the and H K s > a small overlap iteria. For comution of galaxies Fig. 3. Rest-frame SEDs of the J s H (blue circles) Brammer and& van Dokkum 2007 H K s (red diamonds) galaxy samples limited to 2 < z Mariska in the Kriek num- phot < 3 and 3 < z phot < 4.5, respectively. Lorentz Center, The SEDs Leiden are normalized to the flux September 16, 2008

18 Comparison to low-z spectroscopic masslimited samples z=2.3 z=0.7 z=0.0

19 Evolution of the Red Sequence Kriek et al. 2008b

20 Reff < 1 Kpc Morphologies of z~2.3 redsequence galaxies van Dokkum et al. (2008)

21 IG. Red-sequence galaxies at z~2.3 van Dokkum et al Relations between size and (total) stellar mass (left panel) and between the average stellar density inside the effective radius and llar mass (right panel). Large symbols with errorbars are the quiescent z 2.3 galaxies. Small symbols are SDSS galaxies, with galaxies t are not on the red sequence in light grey. Broken lines indicate the expected location of galaxies with stellar velocity dispersions of 200, Kriek Center, September 16, , Mariska and 500 km s!1. The high redshift galaxies are muchlorentz smaller and denserleiden than SDSS galaxies of the same stellar mass.

22 >30 hour spectrum Kriek et al. in prep

23 Absorption lines

24 Active Galactic Nucleus?

25 Red-sequence galaxies at z~2.3

26 Conclusions A red sequence of massive field galaxies with quiescent stellar populations was already in place at z~2.3 The number density of the massive end of the red sequence grows by a factor of ~8 between z~2.3 and the present The z~2.3 red-sequence galaxies still have to grow to evolve into their local analogs Several (if not most) red-sequence galaxies at z~2.3 have actively accreting black holes