The First Cosmic Billion Years. Andrea Ferrara Scuola Normale Superiore, Pisa, Italy

Transcription

1 The First Cosmic Billion Years Andrea Ferrara Scuola Normale Superiore, Pisa, Italy

2 DAVID The Dark Ages VIrtual Department S. Bianchi INAF/Arcetri B. Ciardi MPA P. Dayal SISSA C. Evoli SISSA A. Ferrara SNS Pisa S. Gallerani OARoma F. Iocco IAP F. Kitaura SISSA M. Mapelli ETH A. Maselli MPA R. Salvaterra INAF/Milano S. Salvadori SISSA R. Schneider INAF/Arcetri L. Tornatore INAF/Trieste M. Valdes IPMU R. Valiante Univ. Firenze

3 First Gyr

4 STRUCTURE FORMATION: INITIAL CONDITIONS Komatsu+2008 Cosmic microwave background Big Bang: the Universe is filled with hot plasma cold T/T 10-5 UV/Optical/IR The gas cools and becomes neutral: recombination The Dark Ages hot Today s structures The first structures begin to form: reionization starts FIR/Radio? Reionization is complete WMAP 5yr Temperature Map

5 STRUCTURE FORMATION: INITIAL CONDITIONS COSMic CONTENT Dunkley Å Big Bang: the Universe is filled with hot plasma Å The g gas cools and becomes neutral: recombination DEF: ΩX=ρx /ρ / cr Û ρcr =3H 3H2/8πG /8 G Dark Ages Cl = Cl {Ωdm, Ωb, ΩΛ + τ, h, wthe +4 spectral pars}

6 STRUCTURE FORMATION: INITIAL CONDITIONS The dark AGes reionization Photon Temperature (1+z) Gas Temperature (1+z) 2 Reionization is complete UV/Optical/IR

7 The First Galaxies/Stars

8 STRUCTURE FORMATION L=1 Mpc Redshift z=10 Voids Galaxy Cluster Filaments First Galaxies DM overdensity ρ/ ρ

9 THE FIRST GALAXIES Big Bang: the Universe is filled with hot plasma L=12 kpc COLLAPSE Dark matter density Gas density

10 THE FIRST galaxies GAS Cooling DM halos virial temperature Cooling function (primordial) Metals cm³ s -1 ] Atomic cooling σ Λ/n² [erg H 2 cooling H 2 COOLING Temperature [K]

11 THE FIRST GALAXIES MASS OF FIRST GALAXIES Big Bang: the Universe is filled with hot plasma The gas cools and becomes neutral: recombination t cool = 3kT/2nΛ(T) < t H = H -1 (z) The Dark Ages The first structures begin to form: reionization starts FIR/Radio? M ~ 10 6 M Reionization is complete UV/Optical/IR Today s structures z ~ 30

12 FIRST STARS ARE MASSIVE THE FIRST STARS Yoshida S olar Rad ddi Envelope: 10 3 M o Core:10-2 M o Infall Rate: 0.01 M o /yr 10 AU (1 AU=8 ligh ht min) Density Maps

13 SUPERNOvaE and METAL ENRICHMENT Mori, AF & Madau 2001 M=10 8 M t = Myr Log(gas density) Box size: 3 kpc 12 kpc z = 9

14 Metal induced FRAGMENTATION CHEMICal FEEDBACK Schneider+ 2002, 2006, Omukai Metallicity: Z = M Z /M H (Z = 0.02) PopIII PopII

15 COSMIC POPIII/POP II TRANSITION CHEMICAL FEEDBACK Tornatore, AF & Schneider 2007 Total Metallic city z=5 z=5 z=3 z=3 Pop III Pop II Fracti ion of PopII I form ming sites

16 cosmic STAR FORMATION history CHEMICAL FEEDBACK Tornatore, AF & Schneider 2007 PopII Z M max [Z cr ] PopII PopIII PopIII

17 FIRST STARS HOST GALAXIES LYMAN ALPHA EMITTERS Iye+ 2006; Kashikawa+ 2006; Nagao Å Big Bang: the Universe is filled with hot plasma Å The g gas cools and becomes neutral: recombination The Dark Ages Å The first structures begin to form: reionization starts FIR/Radio? Lyα line Spectrum Spect u Template Å Reionization is complete UV/Optical/IR Å Today s structures

18 Cosmic Reionization

19 L=4 Mpc CosMIC REIONIZATION Gnedin 2000; Gnedin, AF, Zweibel 2000; Ciardi, AF, White+03; Alvarez+2007 J 0 / erg s -1 cm -2 Hz -1 sr -1 Neutral H UV fraction Background a = 1/(1+z) Gas Overdensity Gas Temperature

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28 Reionization completed

29 REIONIZATION TESTS Redshift Neutral IGM z z i. z<z i z>z i Wavelength Wavelength Wavelength Lyα Forest Absorption Patchy Absorption Black Gunn-Peterson trough

30 GUNN-PETERSON EFFECT Spectra of fhigh-zh QSOs TRASMISSION REIONIZATION TESTS Lyα optical depth Fan 2006 (1+z) >10 (1+z) 4.3 (Fan)

31 REIONIZATION TESTS WMAP RESULTS Polarization ation Maps: Q-Stokes Parameteramete rization ure-polar emperatu pectrum Cross Po ower Te Sp Reionization Electron fraction 1 0 τ e = ± Redshift

32 REIONIZATION HISTORY GLOBAL REIONIZATION MODELs Choudhury & AF 2005, 2006 Electron sc. optical depth Lyman Limit Systems Gunn-P Peterson Lyα G-P optical depth Lyman Alpha Emitters Counts Lyβ G-P optical ldepth Gamma Ray Bursts Temperature

33 The Future

34 THE DARK AGES HI 21 CM line EMISSION u 21 cm l n u /n l = 3exp( 0.07K/T s ) HI ground state t Ideal probe of neutral H at high-z different observed frqs. different z (ν~150,120,80 MHz z~8,11,18) CMB photons are absorbed thermal equilibrium T S TCMB Scattering with Lyα photons DECOUPLING

35 LOFAR DETECTION OF REIONIZATION Valdes Simulated Synthetic z=10.6, ν=122 MHz Synthetic LOFAR observation of a simulated reionization history z=9.89, ν=130 MHz Brightness temperature T b = I ν c 2 /2k ν z=9.26, ν=138 MHz log (δt b /K)

36 PERSPECTIVES FUTURE OUTLOOK HI 21cm line detection ti from Dark Ages/EoR Constrain reionization history Detecting reionization sources/first stars Detecting high-z molecules/dust CMB secondary anisotropies: patchy reionization Search for high-z Gamma Ray Bursts

37 The End