Introduction Method Simulations and observations The End The bursty cosmic dawn Outline 1 Introduction Umberto Maio Motivations Leibniz Institute for Astrophysics Potsdam (Germany) 2 Method INAF – Osservatorio Astronomico di Trieste (Italy) Astrochemistry . Simulations and observations .................................................... 3 Pop III–II, SFR, Z, M UV in collaboration with: M. Petkova, B. Ciardi, K. Dolag, CDM and WDM L. Tornatore, J. Johnson, R. Salvaterra, N. Yoshida, 4 The End L. Koopmans, V. Müller, V. Biffi, M. Viel, E. Tescari, Q. Ma ....................................................
Introduction Method Motivations Simulations and observations The End Motivations Goal: Primordial galaxy formation and evolution and the occurrence of chemical (heavy) elements in the Universe: → What is the formation epoch of first objects? → What is the role of molecules and metals in the early ISM? → How relevant is ‘PopIII’ star formation and metal spreading? → How fast is the transition to the standard popII regime? → What are the effects of different IMFs on SFR? → What are the implications for early observables (LF , GRB, Z)? → What are the effects of the underlying matter distribution?...
Introduction Method Astrochemistry Simulations and observations The End Astrochemistry For a complete picture − → follow gravity and hydrodynamics coupled to molecule formation (e.g. Galli& Palla, 1998; Abel et al., 1997) and metal production from stellar evolution (e.g. Tinsley, 1980; Matteucci, 2001) through cosmic time molecules stellar evolution metals determine determines yields determine first gas subsequent collapsing events and timescales structure formation Following and implementing metal and molecule evolution in numerical codes (e.g Gadget, etc.) required (Springel, 2001, 2005; Yoshida et al., 2003; Tornatore et al., 2007; Maio et al., 2007, 2010, 2011; Biffi & Maio, 2013)
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Primordial regimes Mass of first stars connected to the existence of a critical metallicity Z crit (e.g. Bromm & Loeb, 2003; Schneider et al., 2003) below which cooling is not efficient: popIII ( Z < Z crit ) − → popII-I ( Z ≥ Z crit ) Numerical simulations exploring different scenarios needed! Simulation set-up (Maio et al., 2010, 2011, Maio & Iannuzzi, 2011; Biffi & Maio, 2013; Maio & Viel, 2014) Λ CDM cosmology (1,7,14,43,143 Mpc a side); molecules, metals, Z crit = ( 10 − 6 , 10 − 5 , 10 − 4 , 10 − 3 ) Z ⊙ assume different popIII IMFs ( → top-heavy/Salpeter) assume different matter distributions ( → G vs non-G) assume different dark-matter flavors ( → CDM vs WDM)
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Results (1/10): effects for different Z crit 10 − 3 Z ⊙ 10 − 6 Z ⊙ Z crit : z=11 z=13 box: 1Mpc 3 ; popIII IMF: top-heavy with slope=-1.35, range=[100 M ⊙ ,500 M ⊙ ] Gas resolution: 116 M ⊙ / h (Maio et al., 2010)
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Results (2/10): primordial populations in the 1st Gyr fraction of popII haloes (i.e. with SFR contribution from popII and mean Z halo > Z crit ) vs z popIII haloes vs z 0.20 1.0 0.15 0.8 SFR halo contribution f haloes (Z>10 -4 Z sun ) 0.6 popII-I 0.10 popIII 0.4 0.05 0.2 0.00 0.0 8 10 12 14 16 18 20 8 10 12 14 16 18 20 redshift z For further investigations and dynamical features see Biffi & Maio (2013)
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Results (3/10): sSFR – early bursty Universe 100.0 10.0 DATA sSFR [Gyr -1 ] Noeske (2007) Daddi (2007) Dunne (2009) 1.0 Pannella (2009) Stark (2009) Yabe (2009) THEORY Michalowski (2010) Schiminovich (2010) Biffi & Maio (2013) Reddy (2012) 0.1 Tescari Ch24-sA-sW (2014) Bouwens (2012) Dayal (2013) Gonzalez (2012) Dave’ sw (2011) Zheng (2012) Dave’ vzw (2011) Stark (2013) Dolag et al. hr3 Coe (2013) 0 5 10 15 Biffi & Maio (2013) z
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Results (4/10): UV luminosity functions at z ∼ 6 − 9 For each galaxy: L λ = L II λ + L III λ in L5, L10, L30 PopII-I SEDs from Starbust99 (Vazquez & Leitherer, 2005). PopIII SEDs from Schaerer (2002). No dust assumed Observational data points from: Bouwens et al., 2007 (circles); z=6 Bouwens et al., 2011 (circles); z=7-8 McLure et al., 2010 (triangles); z=7-8 Oesch et al., 2012 (squares); z=8 Fit: Su et al., 2012 (solid line); z=6. Resulting slope : ∼ − 2 consistent with HUDF data (Dunlop et al., 2013; Dayal, Dunlop, Maio, Ciardi, 2013) Salvaterra, Maio, Ciardi, Campisi (2013)
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Implications for high- z GRB hosts Tracing LGRBs from the SFR of their host galaxies d N GRB ( Log 10 ( SFR [ M ⊙ / yr ])) Differential GRB hosting probability → d P = N GRB dLog 10 ( SFR [ M ⊙ / yr ]) Large objects (high SFR) are rarer than small objects (low SFR): high- z GRBs are more likely found in intermediate-, low-size objects!
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Results (5/10): Statistical properties of GRB hosts M UV ∼ − 14 ( M ⋆ ∼ 10 7 M ⊙ ) SFR ∼ 0 . 01 − 0 . 1 M ⊙ / yr sSFR ∼ 5 − 10 Gyr − 1 Z ∼ 5 × 10 − 2 Z ⊙ Data from: Tanvir et al., 2012; Thöne et al., 2013; Hartoog et al., 2014; Chornock et al. 2014 See: Salvaterra et al. (2013, 2015); Ma et al. (2015)
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Results (6/10): PopIII-GRB rates and hosts LGRB rate: Detectable fraction (by BAT/Swift) of PopIII GRBs: different progenitors ∼ 10 % at z > 6 i.e. stars with � 40 % at z > 10 (Campisi, Maio, Salvaterra, Ciardi, 2011) 1: Z > Z crit → any popII-I NB: SC sub-sample accounts for only 2: Z crit < Z ≤ 0 . 5 Z ⊙ ∼ 1 % at z > 6 (Maio & Barkov, 2014) → low-Z popII PopIII-GRB-hosts : 3: Z ≤ Z crit the highest probability of finding PopIII GRBs in hosts → f GRBup = 0 . 006 with M ⋆ < 10 7 M ⊙ and Z � Z crit (efficient pollution) → f GRBup 2 = 0 . 022 (upper limits from Swift) dz ′ γ b ζ BH f GRB dV Z Z Ψ( L ′ ) dL ′ R GRB = ρ ⋆ ˙ ( 1 + z ′ ) dz ′ 4 π Lth ( z ′ ) z R GRB : gamma-ray burst rate, γ b : beaming factor, ζ BH : fraction of expected BH (IMF), f GRB : fraction of expected GRB from collapse onto a BH (Swift), ˙ ρ ⋆ : star formation rate density (simulation), Ψ( L ) : Schechter luminosity fct. (assumption), L th : instrumental sensitivity (Swift), Z crit = 10 − 4 Z ⊙ PopIII IMF: top-heavy over [100, 500] M ⊙ PopII IMF: Salpeter over [0.1, 100] M ⊙
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Results (7/10): PopIII stellar populations at z � 5? Indirect signatures: Number of Particles [C/O] 0.4 6 10 z=13 z=13 abundance ratios 0.3 Fraction 4 10 0.2 2 GRB 050904 ( z = 6 . 3): no PopIII 10 z=17.0 0.1 Number of Particles [ C / O ] = − 0 . 1 , [ S / O ] = 1 . 3 [Mg/O] z=13.0 6 10 z=9.5 [ Si / O ] = − 0 . 3 , Z ≃ 0 . 03 Z ⊙ 0 0 z=8.1 z=6.69 (Kawai et al., 2006; Thöne et al., 2013) 4 10 z=5.25 0.3 z=8.1 z=8.1 Fraction GRB 130606A ( z = 5 . 9): unlikely PopIII 2 0.2 10 [ S / O ] < 1 . 24 , [ Si / O ] < 0 . 55 Number of Particles [Si/O] 6 10 [ Fe / O ] < − 0 . 34 , 0.1 Z ≃ 0 . 1 Z ⊙ − 0 . 01 Z ⊙ 0 0 4 10 (Castro-Tirado et al., 2013) 0.3 z=5.25 z=5.25 Fraction 2 10 GRB 111008A ( z = 5 . 0): unlikely PopIII Number of Particles 0.2 [S/O] [ S / H ] = − 1 . 7 , Z � 0 . 01 Z ⊙ 6 10 (Sparre et al., 2014) 0.1 4 10 0 GRB 100219A ( z = 4 . 7): unlikely PopIII −5 −4 −3 −2 −1 −5 −4 −3 −2 −1 2 [ C / H ] = − 2 . 0 , [ Fe / H ] = − 1 . 9 log 10 ( Z [Z ⊙ ]) log 10 ( Z [Z ⊙ ]) 10 Number of Particles [Fe/O] [ O / H ] = − 0 . 9 , [ S / H ] = − 1 . 1 6 10 PopII-I star forming haloes Z ≃ 0 . 1 Z ⊙ PopII-I star forming haloes pre-enriched by popIII 4 (Thöne et al., 2013) 10 2 10 Ma, Maio et al. (2015) −1.2 −0.8 −0.4 0 0.4 0.8 1.2 Element Abundance
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End Effects of CDM and WDM – WDM mass compatible with 10 -2 CDM currently known cosmological WDM 3keV observables: 3 keV 10 -3 ∆ 2 (k) – WDM described by a sharp 10 -4 decrease of P( k ) at large k – Implications for IGM, lensing, 10 -5 0.1 1.0 10.0 100.0 clustering, satellite problem k [h/Mpc] P WDM / P CDM = T 2 (k) 1.0 – What about primordial epochs? 0.8 0.6 0.4 → Sims. L = 10 Mpc / h , 2 × 512 3 0.2 − 0.0 0.1 1.0 10.0 100.0 k [h/Mpc] See Maio & Viel (2015)
Introduction Pop III–II, SFR, Z, M UV Method Simulations and observations CDM and WDM The End CDM and WDM structures CDM WDM
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