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Bi-modality and Do w n s i z i n g

Bi-modality and Do w n s i z i n g. Origin of E vs S Galaxies. Avishai Dekel HU Jerusalem. Bernard ’ s Cosmic Stories, Valencia, June 2006. A third type of Bernard ’ s students:. Those who were inspired by Jones ’ 1976 review. Birnboim & Dekel 03. Dekel & Birnboim 06.

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Bi-modality and Do w n s i z i n g

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  1. Bi-modalityandDownsizing Origin of E vs S Galaxies Avishai Dekel HU Jerusalem Bernard’s Cosmic Stories, Valencia, June 2006

  2. A third type of Bernard’s students: Those who were inspired by Jones’ 1976 review

  3. Birnboim & Dekel 03 Dekel & Birnboim 06 Cattaneo, Dekel et al. 06 Summary Q: z<2:Bright, red & dead, E’s. No big blues. ………….Bi-modality, environment dependence A: Shutdown in Mhalo>1012 Trigger: virial shock heating (threshold mass) ……..Maintenance: “AGN feedback” (?) Q: z~2-4: Massive, high-SFR disks(?) A: Cold flows (+mergers) even in Mhalo~1012 Seleson & Dekel 06 Q: Downsizing? Neistein, van den Bosch & Dekel 06 A1: Not anti-hierarchical for DM halos ! A2: Feedback in Mhalo<1012 & the shutdown in Mhalo >1012 Cattaneo, Dekel, Faber 06 Q: From the blue to the red sequence A: Two tracks: early/late shutdown, wet/dry mergers Dekel et al. 05; Dekel & Cox 06

  4. M*crit~3x1010Mʘ Bi-modality in color, SFR, bulge/disk 0.65<z<0.75 E/S0/Sa Disks and Irregulars Bell

  5. Color-Magnitude bimodality & B/D depend on environment~halo mass environment density: low high very high disks spheroids Mhalo<6x1011 “field” Mhalo>6x1011 “cluster” SDSS: Hogg et al. 03

  6. z<1 z~1 z~3 z~1 Downsizing 0.65<z<0.75 E/S0/Sa Disks and Irregulars Bell

  7. Standard Picture of Infall to a Disk Rees & Ostriker 77, Silk 77, White & Rees 78, … Perturbed expansion Halo virialization Gas infall, shock heatingat the virial radius Radiative cooling Accretion to disc if tcool<tff Stars & feedback M<Mcool ~1012-13M⊙

  8. Growth of a Massive Galaxy T °K 1012Mʘ 1011Mʘ shock-heated gas “disc” Spherical hydro simulationBirnboim & Dekel 03

  9. A Less Massive Galaxy T °K 1011Mʘ shocked cold infall “disc” Spherical hydro simulationBirnboim & Dekel 03

  10. Hydro Simulation: ~Massive M=3x1011 Kravtsov et al. virial shock z=4 M=3x1011 Tvir=1.2x106 Rvir=34 kpc virial shock

  11. virial radius coldinfall Less Massive M=1.8x1010 Kravtsov et al. z=9 M=1.8x1010 Tvir=3.5x105 Rvir=7 kpc

  12. disk cold flows shock-heated adiabatic infall Mass Distribution of Halo Gas density Temperature Analysis of Eulerian hydro simulations by Birnboim, Zinger, Dekel, Kravtsov

  13. Shock-stability analysis (Birnboim & Dekel 03): post-shock pressure vs. gravitational collapse Gas through shock: heats to virial temperature compression on a dynamical timescale versus radiative cooling timescale

  14. 300 100 Vvir [km/s] 250 120 Birnboim & Dekel 03; Dekel & Birnboim 06 Shock-Heating Scale stable shock Mvir [Mʘ] 6x1011 Mʘ unstable shock

  15. shock heating Fraction of cold gas in halos: Eulerian simulations Birnboim, Dekel, Kravtsov, Zinger 2006 z=3 z=4 z=1 z=2

  16. Fraction of cold/hot accretion SPH simulation Keres, Katz, Weinberg, Dav’e 2004 sharp transition Z=0, under-estimate Mshock

  17. 1013 1012 1011 M* of Press Schechter 0 1 2 3 4 5 Cold Flows in Typical Halos shock heating Mvir [Mʘ] 2σ (4.7%) at z>1 most halos are M<Mshock→cold flows 1σ (22%) redshift z

  18. shock no shock At High z, in Massive Halos: Cold Streams in a Hot Medium in M>Mshock Totally hot at z<1 Cold streams at z>2 cooling

  19. Cold, dense filaments and clumps (50%)riding on dark-matter filaments and sub-halos Birnboim, Zinger, Dekel, Kravtsov

  20. Cold flows riding dark-matter filaments gas temperature gas density dark matter

  21. cold filaments in hot medium Mshock~M* Mshock>>M* M* Cold Streams in Big Galaxies at High z 1014 1013 1012 1011 1010 109 all hot Mvir [Mʘ] Mshock all cold 0 1 2 3 4 5 redshift z

  22. high-sigma halos: fed by relatively thin, dense filaments → cold flows typical halos: reside in relatively thick filaments, fed ~spherically → no cold flows the millenium cosmological simulation

  23. one thick filament several thin filaments Dark-matter inflow in a shell 1-3Rvir Seleson & Dekel density temperature radial velocity M~M* M>>M*

  24. Dense radial streams into high-sigma halos M~M* fraction of halos M>>M* fraction of mass outside the virial radius with high density & radial motions

  25. Once the gas is shock heated, what keeps it hot? cold hot photo-ionization 1 AGN + hot medium SN UV on dust feedback strength AGN feedback could be effective in massive galaxies Supernova feedback is not effective in massive galaxies dynamical friction in groups 0 Most efficient star formers: Mhalo~1011-12 109 1010 1011 1012 1013 1014 Mvir [Mʘ]

  26. Shock Heating Triggers “AGN Feedback” In M>Mshock Enough energy in AGNs (but no characteristic mass) Hot, dilute gas is vulnerable to AGN feedback, while cold streams are shielded Shock heating is the trigger for “AGN fdbk” Kravtsov et al. Mshock provides the threshold for shutdown, AGNs may provide long-term maintenance

  27. Cosmological Hydro Simulations Slyz & Devriendt 2005 dark halos dark matter gas density temperature dense, cooled gas clumps a dilute medium

  28. A blast wave expanding in a two-phase medium dark matter gas density temperature dense clumps are shielded dilute gas is pushed away

  29. The clumpy cold flows themselves may provide the maintenance of shutdown Birnboim & Dekel The role of AGNs in the shutdown may be minor Birnboim, Zinger, Dekel, Kravtsov

  30. Origin of the Bi-modality Dekel & Birnboim 06 cold vs hot ungrouped vs grouped SN feedback vs “AGN feedback” 15

  31. Cold flows → star burst Streams collide near center -- isothermal shock & efficient cooling → dense, cold slab → star burst Disk can survive Hot medium →halt star formation dilute medium vulnerable to “AGN fdbk” → shock-heated gas never cools → shut down disk and star formation Two Key Processes:

  32. From blue sequence to red sequence Dekel & Birnboim 06 1014 1013 1012 1011 1010 109 cold hot in hot Mvir [Mʘ] Mshock all cold 0 1 2 3 4 5 redshift z

  33. z=0 excess of big blue no red sequence at z~1 data --- sam --- not red enough too few galaxies at z~3 star formation at low z In a standard Semi Analytic Model (GalICS) Cattaneo, Dekel, Devriendt, Guiderdoni, Blaizot 05 color color u-r magnitude Mr

  34. With Shutdown Above 1012 Mʘ color u-r magnitude Mr

  35. Standard color u-r magnitude Mr

  36. With Shutdown Above 1012 Mʘ color u-r magnitude Mr

  37. Bulge to disk ratio Environment dependence via halo mass

  38. later growth & shutdown early growth & shutdown passive ~bright blue z~2 very bright blue z~3 dry mergers dry mergers z=1 z=1 z=2 early wet mergers wet mergers z=2 z=3 z=3 stellar mass stellar mass How Bright Ellipticals make it to the Red SequenceTwo Types of tracks:(Cattaneo, Dekel, Faber 06) z=1 z=1 z=2 z=2 z=3 z=3 magnitude MV magnitude MV

  39. Downsizing: epoch of star formation in E’s Thomas et al. 2005

  40. z=2 z=1 z=1 z=3 in place by z~1 turn red after z~1 Downsizing due to Shutdown Cattaneo, Dekel, Faber 2006 brightintermediate faint . central central/satellites satellites z=0 z=1 color magnitude

  41. z=2 Mhalo>1012 z=1 Mhalo>1012 Mhalo>1012 z=0 central small small satellite big Downsizing by Shutdown at Mhalo>1012 The bright red & dead E’s are in place by z~1 while smaller E’s appear on the red sequence after z~1

  42. Downsizing by Shutdown at Mhalo>1012 big red & dead already in place by z~1 cold filaments in hot medium big small enter the red sequence after z~1 small central merge into big halo small satellite M* 1014 1013 1012 1011 1010 109 all hot Mvir [Mʘ] Mshock all cold 0 1 2 3 4 5 redshift z

  43. Downsizing by Feedback and Shutdown cold hot 1 AGN + hot medium SN feedback strength Regulated SFR, keeps gas for later star formation in small halos Shutdown of star formation earlier in massive halos, later in satellites 0 109 1010 1011 1012 1013 1014 Mvir [Mʘ]

  44. Upsizing of mass in main progenitor Downsizing of mass in all progenitors >Mmin Is Downsizing Anti-hierarchical? Merger trees of dark-matter halos M>Mmin z=2 z=1 Neistein, van den Bosch, Dekel 2006 z=0 big mass small mass

  45. Natural Downsizing in Hierarchical Clustering Neistein, van den Bosch, Dekel 2006 Formation time when half the mass has been assembled EPS all progenitors downsizing main progenitor upsizing

  46. Conclusions 1.Galaxy type is driven by dark-halo mass: ...Mcrit~1012Mʘ by shock heating (+feedback & clustering) 2. Disk & star formation by cold flowsriding DM filaments 3. Early (z>2) big halos (M~1012)....big high-SFR galaxies by cold flows in hot media 4.Late (z<2) big halos M>1012(groups): ...virial shock heating triggers “AGN feedback”.…→ shutdown of star formation → red sequence 5. Late (z<2) small halos M<1012(field):blue disks M*<1010.5 6. Downsizing is seeded in the DM hierarchical clustering 7. Downsizing is shaped up by feedback & shutdown M>1012 8. Two different tracks from blue to red sequence

  47. Thank you

  48. Thank you

  49. non-dissipative R dissipative, with gas-fraction declining with mass M* Tilted Scaling Relations by Differential Dissipative Mergers Dekel & Cox 2006

  50. Structural changes in dissipative mergers Dekel & Cox 2006

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