The First Cosmic Billion Years Andrea Ferrara Scuola Normale Superiore, Pisa, Italy
DAVID The Dark Ages VIrtual Department http://www.arcetri.astro.it/twiki/bin/view/david/webhome 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
First Gyr
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
STRUCTURE FORMATION: INITIAL CONDITIONS COSMic CONTENT Dunkley+ 2008 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}
STRUCTURE FORMATION: INITIAL CONDITIONS The dark AGes reionization Photon Temperature (1+z) Gas Temperature (1+z) 2 Reionization is complete UV/Optical/IR
The First Galaxies/Stars
STRUCTURE FORMATION L=1 Mpc Redshift z=10 Voids Galaxy Cluster Filaments First Galaxies DM overdensity ρ/ ρ
THE FIRST GALAXIES Big Bang: the Universe is filled with hot plasma L=12 kpc COLLAPSE Dark matter density Gas density
THE FIRST galaxies GAS Cooling DM halos virial temperature Cooling function (primordial) Metals cm³ s -1 ] Atomic cooling 5 4 3 2 1σ Λ/n² [erg H 2 cooling H 2 COOLING Temperature [K]
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
FIRST STARS ARE MASSIVE THE FIRST STARS Yoshida+2008 25 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
SUPERNOvaE and METAL ENRICHMENT Mori, AF & Madau 2001 M=10 8 M t = 0-175 Myr Log(gas density) Box size: 3 kpc 12 kpc z = 9
Metal induced FRAGMENTATION CHEMICal FEEDBACK Schneider+ 2002, 2006, Omukai+ 2006 Metallicity: Z = M Z /M H (Z = 0.02) PopIII PopII
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
cosmic STAR FORMATION history CHEMICAL FEEDBACK Tornatore, AF & Schneider 2007 PopII Z M max [Z cr ] PopII PopIII PopIII
FIRST STARS HOST GALAXIES LYMAN ALPHA EMITTERS Iye+ 2006; Kashikawa+ 2006; Nagao+ 2007 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
Cosmic Reionization
L=4 Mpc CosMIC REIONIZATION Gnedin 2000; Gnedin, AF, Zweibel 2000; Ciardi, AF, White+03; Alvarez+2007 J 0 / 10-21 erg s -1 cm -2 Hz -1 sr -1 Neutral H UV fraction Background a = 1/(1+z) Gas Overdensity Gas Temperature
Reionization completed
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
GUNN-PETERSON EFFECT Spectra of fhigh-zh QSOs TRASMISSION REIONIZATION TESTS Lyα optical depth Fan 2006 (1+z) >10 (1+z) 4.3 (Fan)
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 = 0.087 ± 0.017 11 Redshift
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
The Future
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
LOFAR DETECTION OF REIONIZATION Valdes+ 2006 Simulated Synthetic -1-1.4-2 -1.6-3 -1.8-4 -5-1 -2 z=10.6, ν=122 MHz -2.0-2.2-1.6-1.8 Synthetic LOFAR observation of a simulated reionization history -3-2.0-4 -2.22-5 -1 z=9.89, ν=130 MHz -2.4-1.6 Brightness temperature -2-3 -1.8-2.0-2.2 T b = I ν c 2 /2k ν 2-4 -5 z=9.26, ν=138 MHz -2.4-2.6 26-2.8 log (δt b /K)
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
The End