Galaxy Formation Made Simple thanks to Sloan! Sloan Science Symposium Sandra M. Faber August 1 5,

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1 Galaxy Formation Made Simple thanks to Sloan! Sloan Science Symposium Sandra M. Faber August 1 5,

2 Outline of talk Part I: Review of basic galaxy formation Part II: Emerging paradigm: mass sequence Part III: Predictions and comparison to data Part IV: Unknowns and future work

3 Computation and visualization by J Diemand, M Kuhlen, and P Madau (UC Santa Cruz) QuickTime and a YUV420 codec decompressor are needed to see this picture.

4 The frothy large-scale distribution of galaxies as revealed by SDSS hift Reds Michael Blanton

5 The Formation of the Milky Way Gas is GREEN Stars are WHITE (DM not shown) QuickTime and a YUV420 codec decompressor are needed to see this picture. By spe c ial pe rmissio n Fabio G o ve rnato, UW

6 Two key components of galaxy formation Hierarchical clustering of dark-matter halos

7 Two key components of galaxy formation Hierarchical clustering of dark-matter halos Simultaneous dissipational collapse of baryons towards centers

8 A third key component: satellites vs. centrals Smaller satellite galaxies can orbit for a time within larger halos without merging onto the central galaxies. Satellite Cluster

9 Dark halo mass growth vs. time: 4 examples GALics DM halos by Cattaneo et al Clusters Groups Milky Way and M31 halo s Galaxies time

10 Dark halos of progressively smaller mass Log (Mhalo/Mv) time 10 Cattane o e t al Redshift, z 6 8

11 A schematic model of average halo mass growth Log (Mhalo/Mv) Star-forming band Redshift, z 6 8

12 A schematic model of average halo mass growth SFR = f(mhalo, z) Log (Mhalo/Mv) Star-forming band C. Conroy, R. Wechsler, D. Croton Redshift, z 6 8

13 A schematic model of average halo mass growth 15? 14 De ke l & Birnbo im 2006 Log (Mhalo/Mv) Star-forming region C. Conroy, R. Wechsler, D. Croton Redshift, z 6 8

14 Stellar mass is uniquely related to halo mass at every redshift z=1 Conroy and Wechsler 2008

15 Stellar mass is uniquely related to halo mass at every redshift MWay today z=1 Conroy and Wechsler 2008

16 A schematic model of average halo mass growth 15 De ke l & Birnbo im Log (Mhalo/Mv) C. Conroy, R. Wechsler, D. Croton Redshift, z 6 8

17 A schematic model of average halo mass growth 15 De ke l & Birnbo im Log (Mhalo/Mv) C. Conroy, R. Wechsler, D. Croton Redshift, z 6 8

18 A schematic model of average halo mass growth 15 De ke l & Birnbo im Log (Mhalo/Mv) C. Conroy, R. Wechsler, D. Croton Redshift, z 6 8

19 A schematic model of average halo mass growth 15 De ke l & Birnbo im Log (Mhalo/Mv) C. Conroy, R. Wechsler, D. Croton Redshift, z 6 8

A schematic model of average halo mass growth 15 14 Red, dead, massive

20 A schematic model of average halo mass growth Red, dead, massive Log (Mhalo/Mv) Blue, active, small Redshift, z 6 8

21 Sloan assets for studying galaxies Huge samples: not only trends but scatter, rare objects, environments Accurate 5-color photometry with considerable spatial resolution 1,000,000 spectra covering wide wavelength range with useful v Dense spatial mapping for correlation functions and environments Homogeneous data Excellent data delivery Large user base, science crosstalk

22 The Galaxy Zoo as Revealed by Sloan 123,000 galaxies Kauffmann e t al Blanto n e t al. 2003

23 The Star-Forming Sequence in Stellar Population Indices Blue, active Red, dead Kauffmann e t al. 2003

24 The star-forming sequence is also a mass sequence Specific SFR based on absorption-corrected GALEX UV flux Blue, active, small Red, dead, massive Log Stellar Mass Samir e t al. 2007

25 Halo-based model is good match to star formation back to z = 1 SDSS, z~0.1: Salim et al DEEP2, z=0.5,1.0: Noeske et al Co nro y & We c hsle r 2008

26 Other trends vs. stellar mass -- Stellar age Mean stellar age Stellar mass G allazzi e t al. 2005: Slo an Surve y

27 Other trends vs. stellar mass -- Interstellar gas metallicity ISM metallicity log[o/h] Tre mo nti e t al. 2004: Slo an Surve y

28 Other trends vs. stellar mass -Surface mass density Kauffmann e t al. 2003: Slo an Surve y

29 Other trends vs. stellar mass -Surface brightness of starforming galaxies De ke l & Wo o 2003

30 Color bimodality seen in Sloan galaxies Red-and dead ellipticals/s0s populate the red sequence Star-forming blue, disky galaxies populate the blue cloud Red sequence Red Blue Spheroids/ ellipticals/ S0s Disks/spirals Color vs. stellar mass for Sloan Digital Sky Survey galaxies

31 Flow through the color-mass diagram for central galaxies Red sequence Dry merging Blue cloud Quenching band

32 Flow through the color-mass diagram for satellite galaxies Red sequence Blue cloud Quenching band

33 Flow through the CM diagram versus environment Ho gg e t al. 2003: Slo an Surve y

34 Flow through the CM diagram versus environment Dry mergers ls Centra llites Sate Ho gg e t al. 2003: Slo an Surve y

35 Color-mag diagram 2003: Sloan version HR diagram 2003: Hipparchos version

36 Color-mag diagram 2003: Sloan version HR diagram 1913: Russell s version

37 Color bimodality back in time: SDSS vs. DEEP2 More! Co nro y e t al. 2007

38 What exactly is the quenching mechanism? Inefficient gas cooling in halos above ~1012 Mv (Rees & Ostriker 1977, Blumenthal et al. 1984, Dekel & Birnboim 2006) Mass surface density threshold (Kauffmann et al. 2006) Stellar winds Merger-driven (Cox et al. 2004) Starburst-driven (Cox et al. 2004) BH growth + AGN feedback (Hopkins et al. 2006; Croton et al. 2006)

39 HR diagram 1913: Russell s version HR diagram 2003: Hipparchos version

40 Critical quenching stellar mass corresponds to M*halo~1012 Mv dead active active dead M *crit~3x1010m ʘ Active = star-forming Dead = red and dead SDSS Kauffmann e t al. 2003

41 SDSS BPT diagram separates star-forming gals from AGNs Brightest AGNs Star-forming Fading AGNs Kauffmann e t al. 2003

42 SDSS BPT diagram: star-forming vs. AGNs?

43 Outline of talk

Origin of Bi-modality

Origin of Bi-modality and Downsizing Avishai Dekel HU Jerusalem Galaxies and Structures Through Cosmic Times Venice, March 2006 Summary Q: z