1. Formation of the first galaxies and reionization of the Universe: current status and problems A. Doroshkevich Astro-Space Center, FIAN, Moscow.

2. Theoretical expectations and observational problems Scientific activity: >17 publications in 2012 z~25 – 10 - formation of the first stars and ionizing bubbles Bubble model, UV-background, non homogeneities in x H and T g z~ 10 WMAP: τ T ~0.1, x H =n H /n b << 1 z~6.5 – 5 - high ionization, x H ~10 -3 z< 3 - x H ~10 -5 1. We do not see any manifestations of the first stars 2. We do not know the main sources of ionizing UV radiation

3. Universe Today 12.12.2012

4. Possible sources of ionizing UV background 1. exotic sources – antimatter, unstable particles, etc… 2. First stars Pop III with Z met <10 -5 Z ¤ or 3. non thermal sources - AGNs and Black Holes 4. Quasars at z < 3.5, He III

5. Reionisation Θ(z)=α(T)n(z)H(z)~3T 4 -0.7 z 10 3/2, T 4 ~2. For z 10 >1 recombination becomes important ! Thermal sources: E~7 MeV/baryon, N γ < 5 10 5 /baryon Non thermal sources - AGNs and Black Hole E~ 50 MeV/baryon, N γ ~3.5 10 6 /baryon Ω met ~2 10 -6 Ω bar ~8 10 -8, Ω bh ~3 10 -7 Ω bar ~ 10 -8 f esc ~ 0.1 - 0.02, N bγ ~1 - 2

6. Labbe I., 2010,ApJ.,708,L26, 1209.3037 Spitzer photometry Z~8, 63 candidats, 20 actually detected SMD for M<-18 ρ * (z=8)~10 6 M s /Mpc 3 Ω * (z=8)~0.4 10 -5 Ω met (z=8)~0.4 10 -7 Ω reio ~10 -7 – 10 -8 z~2.5, Ω met ~2.3 10 -6 for IGM, Ω met ~3 10 -5 for galaxies

7. Three steps of galaxy formation 1. Formation of the virialized relaxed massive DM cloud (perhaps, anisotropic) at z<z rec ~10 3 with ρ cl ~200 and overdensity δ DM ~10 4 z 10 7 M 9 1/2 2. Cooling and dissipative compression of the baryonic component, but the bulk motions and the kinetic temperature of stars are preserved 3. Formation of stars – luminous matter with M>M J Main Problem of the star formation M J /M ¤ ~2 ·10 7 T 4 3/2 n b -1/2, For stars: T 4 ~10 -2, n b >10 2 cm -3, M J /M ¤ <10 3 z=z rec,T 4 ~0.3, n b ~250 cm -3, M J / M ¤ ~ 2 ·10 5 Parameters of baryonic components ~4·10 -28 z 10 3 g/cm 3, ~10 -24 g/cm 3, ~1 g/cm 3, ρ BH ~2 M 8 -2 g/cm3 Cooling factors: H 2 molecules and metals (dust, C I etc.)

8. Simplest problem – first galaxies and POP III stars Two processes of the H 2 formation H+e=H - +γ, H - +H=H 2 +e, γ~1.6eV H+p=H 2 + +γ, H 2 + +H=H 2 +p E par =128K, E ort =512K In both case the reaction rate and the H 2 concentrations are proportional to = At 1000>z>z rei x e =n e / ~10 -3 what is very small value. Feedback of LW radiation 912A<λ<1216A H 2 +γ LW =2H

9. Influence of the LW background Actual limit is J LW21 ~1 – 0.1 for various redshifts For the period of full ionization z~10 we get J LW 21 ~4 N bγ This means that at at 10>z>8.5 the H 2 molecules are practically destroyed and star formation is strongly suppressed This background is mainly disappeared at z~8.5

10. Safranek-Shrader, 1205.3835 Corrections for both limits ~10 times J 21 ~4N b γ

11. Simulations (2001) The box ~1Mpc, 128 -256 cells, N dm ~10 7, m dm ~30M 0, M gal ~10 6 – 10 7 M 0 Very useful general presentation (the galaxy and star formation are possible) Restrictions: a. small box → random regions (void or wall) & unknown small representativity b. large mass DM particles in comparison with the mass of stars.

12. What is mostly interesting a. realization – it is possible! b. wide statistics of objects -- what is possible for various redshifts c. rough characteristics of internal structure of the first galaxies d. general quantitative analysis of main physical processes

13. Density – temperature 2001

14. Machacek et el. 2001, ApJ, 548, 509 M~5 10 5 M s T 4 ~0.3 n b ~10cm -3 f H2 ~3 10 -5 j 21 ~1 M J (25)~10 4 M s M J (20)~500M s Lazy evolution, Monolitic object Monotonic growth ρ(z)??? Instabilities!

15. Smith, B.,2008, MNRAS, 385, 1443

16. Cooling functions.

17. ρ, T & Z, Wise 1011.2632 Formation of massive galaxies owing to the merging of low mass galaxies.

18. Comments Importance – instead of the experiment Complexity, representativity and precision (WMAP). Modern facilities Our attempts – simulations versus analysis

19. New semi analytical approach We know the process of the DM halo formation and can use this information Assumptions: a. what is the moment of halo formation b. baryons follow to DM and have the same pressure and kinetic temperature c. what is the cooling of the baryonic components d. thermal instability leads to formation of stars with masses M st > M Jeans

20. Analytical characteristics for DM component For the NFW halo with mass M=10 9 M 9 M s formed at z f =(1+z)/10 Within central core with r< r s we have ρ DM ~10 -23 g/cm 3 M 9 1/2 z f 10, T DM ~40 eV M 9 5/6 z f 10/3 m DM /m b Cooling factors: H 2 and atomic for T 4 >1, Three regimes of the gas evolution – slack, rapid and isothermal Thermal instability and the core formation Stars are formed for T bar 100cm -3 with M star > M J ~5 10 7 T 4 3/2 /n bar 1/2 M s

21. Formation of the first stars with M cl /M 0 = 3 10 5 and 7 10 5, z f =24 (left) and M cl /M 0 =0.7 10 8 and 3 10 8, z f =11 (right)

22. Low mass limit for the rapid-lazy formation of the first galaies

23. SN explosions W=GM 2 /R vir ~3·10 55 z 10 M 9 5/3 erg E SN ~10 52 – 10 55 erg D ex <0.2 – 0.5 Mpc - IGM impact For M 9 >0.1 we have SN metal enrichment within galaxy, otherwise – matter ejection Low massive stars, satellites and merging

24. Universe Today 1211.6804

25. Ellis et al. arXiv1211.6804

26. Bradley L., 1204.3641, UV luminosity function for z~8 Low massive objects dominate Why? Is this selection effect? What about object collections? suppression of object formation ? What is at z=9? 10?

27. Behroosi et al. 1209.3013

28. Behroozi et al., 1209.3013 - SFR(M h ) SMF~M h -4/3, M>M ch ; SMF~M h 2/3, M<M ch (left panel) M s /M h <2 – 3% at all z! ?continual evolution?

29. comments Stars occupy very small matter fraction ? Low massive objects dominate at all redshifts? Is this impact of nature or selection effect? Formation of the massive galaxies owing to the merging of satellites with stars?? Illingworth 1977 for 13 E-galaxies Fraction of massive objects increases more rapidly – merging of satellites or other factors?? Small scale perturbations and missing satellite problem – when and where had been formed dwarf galaxies.

30. Tollerud et al. 2008, ApJ, 688, 277 Observations of the Milky Way satellites with different corrections

31. 16 observed dSph galaxies (Walker et al.2009) dominated by DM component DM parameters ρ~ 0.07M 6 1/2 f 3 (M 6 ) P~37f 4 (M 6 ) S~14M 6 0.83 /f(M 6 ) Z 10 =0.9M 6 -0.1 Bovill & Ricotti, 2009, ApJ, 693,1859 Tollerud et al. 2008

32. Conclusions We do not see any manifestations of the first stars We do not know the main sources of ionizing UV radiation A. It seems that first stars Pop II & III, SNs, GRBs are approximately effective (~30 – 40%) B. non thermal sources BHs remnants and/or AGNs are more effective (~50% + ?) C. We can semi analytically describe the formation and evolution of the first galaxies

33. Galaxies and BHs BHs are observed in~1% of all galaxies, n~10 -4 Mpc -3 Very massive BHs are observed as QSRs with N qsr ~10 -5 – 10 -6 Mpc -3 at z<5; mainly at z~2 – 2.5 Perhaps, there are AGNs in 70% of old massive galaxies. ρ BH ~3 10 -2 M 9 -2 g/cm 3, ρ DM ~10 -23 z f 10 M 9 0.5 g/cm 3 within halo

34. Vestergaard et al. 2008

35. BH-distributions: M(z) & L/L ed Vestergaard, Osmer, 2009, ApJ,699,800

36. Number density of the SMBH, Kelly et al., 2011, 1006.3561

37. BH evolution 1. We see rare supermassive BH at z<2 - early formation and short lifetime. 2. Impact of the accretion rate. 3. Are the SMBH primordial? 4. van den Bosch, Nature, arXiv:1211.6429 NGC 1277, M~1.2 10 11 M ☼, M BH ~1.7 10 10 M ☼ 5. Nature: Simcoe et al., 2012, QSR ULASJ120+064, z=7.08, Z met < 10 -4 Z ☼

38. SMBH formation Accretion of baryons from a thin/thick or HMD disk, major or minor mergers, from Pop III BH remnants (Shapiro 2005). Problems: small mass of remnants (<10 3 M ☼ ) For the observed SMBHs M BH ~(10 5 – 10 10 )M ☼ The expected mass amplification is (10 3 – 10 4 ). Primordial BH (Ricotti et al. 2007, Duching 2008)

39. Three scenario of the BH formation

40. The end

41. Redshift variations of intensity of the UV background

42. SMGs, Yun et al., 1109.6286

43. Behroozi et al., 1207.6105 Stellar mass vs. host halo Similarity of the curves

44. Gonzalez V., 2011, ApJ, 735, L34

45. Observed galaxies and IGM Ω met as the cumulative measure z~10 Ω reio >(1 – 8)10 -8 z~0, Ω met ~5.7 10 -4 z~2.5 Ω met ~3. 10 -5 for galaxies with M star >10 9 M o z~7, Ω star ~4 10 -6, Ω met ~10 -2 Ω star ~4 10 -8 Possible explanations : a. Low massive galaxies ?, b. non thermal sources c. strong non homogeneity (bubbles)

46. UV luminosity density Oesch P., 2012, ApJ.745, 110

47. M J, Bromm et al., 1102.4638

48. XXXXXX OBSERVATIONS 5-year WMAP data: τ e =0.087±0.017, z rec =10.8±1.4 However: Pol~ΔT 2 τ e, and ΔT 2 (DV)=2ΔT 2 (WMAP) Therefore, τ e <0.9 and z rec <10.8 BUT Quasars and galaxies are seen at z~8 - 9 τ e ~0.04 – 0.05, z~7 τ e ~Δτ e ~0.001 – 0.06, 7< z <1000 One object at z~9.5,

49. Observed galaxies and IGM Ω met as the cumulative measure We like to have at least f esc ~0.1 – 0.01, N bp >1, N ph ~5 10 5 Ω min =Ω b N bp (f esc N ph ) -1 ~10 -7 (N bp /f esc )(Ω b /0.04) ----------------------------------------------------------------------------------------------------------------- z~2.5, Ω met ~3 10 -5 for galaxies, z~2.5, Ω met ~2.3 10 -6 for IGM, -------------------------------------------------------------------------------------------------------------------------------------- z~5, Z met =0.1Z ☼ ~2 10 -3, Ω * ~6.7 10 -5, Ω met =Ω * Z met ~ 1.3 10 -7 for galaxies Ω C ~(5±1.7) 10 -8, z 5.5,