History of IGM bench-mark in cosmic structure formation indicating the first luminous structures Epoch of Reionization (EoR) C.Carilli (NRAO) CfA Sept 2004 ionized neutral ionized

z=5.80 z=5.82 z=5.99 z=6.28 The Gunn Peterson Effect Fan et al 2003 Fast reionization at z =6.3 => opaque at _obs <0.9  m f(HI) > at z = 6.3

Neutral IGM evolution (Gnedin 2000): ‘Cosmic Phase transition’ at z=6 to 7 Log (HI fraction) DensityGas Temp Ionizing intensity Normalization: GP absorption, LCDM + z=4 LBGs, T _IGM 8 Mpc (comoving)

Thompson scattering at EoR   e = 0.17 => F(HI) < 0.5 at z=17 Extended period of reionization: z=6 to 15? WMAP Large scale polarization of CMB (Kogut et al.) 20deg

Fan et al Near-edge of reionization: GP Effect Fairly Fast: f(HI) > 1e-3 at z >= 6.4 (0.87Gyr) f(HI) < 1e-4 at z <= 5.7 (1.0 Gyr)

Complex reionization example: Double reionization? (Cen 2002) Pop III stars in ‘mini-halos’ (<1e7 M _sun) ‘normal’ galaxies (>1e8M _sun)

Limitations of current measurements: CMB polarization: --  _e = Ln _e   e = integral measure through universe => allows many reionization scenarios Gunn-Peterson effect: --  _Lya >>1 for f(HI)> High z universe is opaque to optical observers

Radio astronomical probes of the Epoch of Reionization and the 1 st luminous objects 1.CMB large scale polarization 2.Objects within EoR – Molecular gas, dust, star formation 3.Neutral IGM – HI 21cm emission and absorption Collaborators USA – Carilli, Walter, Fan, Strauss, Owen, Gnedin Euro – Bertoldi, Cox, Menten, Omont, Beelen SKA Key Program science team– Briggs, Carilli, Furlanetto, Rawlings Science with the Square Kilometer Array (NAR, Carilli & Rawlings)

 IRAM 30m + MAMBO: sub-mJy sens at 250 GHz + wide fields  IRAM PdBI: sub-mJy sens at 90 and 230 GHz + arcsec resol.  VLA: uJy sens at 1.4 GHz  VLA: < 0.1 mJy sens at GHz + 0.2” resol.

Magic of (sub)mm L _FIR = 4e12 x S _250 (mJy) L _sun for z=0.5 to 8

SDSS + DPOSS: 700 at z > 4 30 at z > 5 9 at z > 6 M _B L _bol > 1e14 L _sun M _BH > 1e9 M _sun York et al 2001; Fan et al High redshift QSOs

QSO host galaxies – M _BH –  relation Most (all?) low z spheroidal galaxies have SMBH M _BH = M _bulge  ‘Causal connection between SMBH and spheroidal galaxy formation’ (Gebhardt et al. 2002)?  Luminous high z QSOs have massive host galaxies (1e12 M _sun )

30% of luminous QSOs have S _250 > 2 mJy, independent of redshift from z=1.5 to 6.4 L _FIR =1e13 L _sun = 0.1 x L _bol : Dust heating by starburst or AGN? MAMBO surveys of z>2 DPSS+SDSS QSOs z= z=6.2 1e13L _sun Arp220

L _FIR vs L’(CO)  M(H_2) = X * L’(CO), X=4 (Milkyway), X=0.8 (ULIRGs)  Telescope time: t(dust) = 1hr, t(CO) = 10hr Index=1.7 Index=1 1e11 M_sun 1e3 M _sun /yr High-z sources

highest redshift quasar known L _bol = 1e14 L _sun central black hole: 1-5 x 10 9 M sun ( Willot etal.) clear Gunn Peterson trough (Fan etal.) Objects within EoR: QSO at z=6.4

z=6.42: MAMBO detection S _250 = 5.0 +/- 0.6 mJy => L _FIR = 1.2e13 L _sun, M _dust =7e8 M _sun  3’

VLA Detection of Molecular Gas at z= GHz CO 3-2 Off channels 50 MHz ‘channels’ (320 kms -1,  z=0.008) noise: ~57  Jy, D array, 1.5” beam  M(H _2 ) = 2e10 M _sun  Size < 1.5” (image),  Size > 0.2” (T _B /50K)^-1/2

IRAM Plateau de Bure confirmation FWHM = 305 km/s z = /  (3-2) (7-6) (6-5) T kin =100K, n H2 =10 5 cm -3 Typical of starburst nucleus

VLA imaging of CO3-2 at 0.4” and 0.15” resolution  Separation = 0.3” = 1.7 kpc  T _B = 20K = T _B (starburst )  Merging galaxies?  Or Dissociation by QSO? rms=50uJy at 47GHz  CO extended to NW by 1” (=5.5 kpc) tidal(?) feature

Phase stability: Fast switching at the VLA 10km baseline rms = 10deg

: radio-FIR SED  Star forming galaxy characteristics: radio-FIR SED, L’ _CO /FIR, CO excitation and T _B => Coeval starburst/AGN: SFR = 1000 M _sun /yr  Stellar spheroid formation in few e7 yrs = e-folding time for SMBH => Coeval formation of galaxy/SMBH at z = 6.4 ? S _1.4 = 55 +/- 12 uJy Beelen et al. T _D = 50 K

M( dust ) = 7e8 M _sun M( H _2 ) = 2e10 M _sun M _dyn (r=2.5kpc) = 5e10 M _sun M _BH = 3e9 M _sun => M _bulge = 1.5e12 M _sun Gas/dust = 30, typical of starburst Dynamical vs. gas mass => baryon dominated? Dynamical vs. ‘bulge’ mass => M –  breaks-down at high z? : Masses

Cosmic (proper) time  T _univ = 0.87Gyr

Age of universe: 8.7e8 yr C, O production (3e7 M _sun ): 1e8 yr Fe production (SNe Ia): few e8 yr (Maiolino, Freudling) Dust formation: 1.4e9yr (AGB winds) => dust formed in high mass stars/SNR (Dunne et al ) ? => silicate grains? => Star formation started early (z > 10)?  Timescales

Cosmic Stromgren Sphere Accurate redshift from CO: z=6.419+/0.001 Ly a, high ioniz. Lines: uncertainty >1000km/s (  z=0.03) Proximity effect: photons leaking from 6.32<z<6.419 z=6.32 ‘time bounded’ Stromgren sphere: R = 4.7 Mpc t _qso = 1e5 R^3 f(HI)= 1e7yrs White et al. 2003

Richards et al SDSS QSOs

Loeb & Rybicki 2000

Constraints on neutral fraction at z=6.4  GP => f(HI) >  If f(HI) = 0.001, then t _qso = 1e4 yrs – implausibly short given fiducial lifetime, f _lt = 1e7 years?  Probability arguments suggest: f(HI) > 0.1 at z=6.4 – much better limit than GP Wyithe and Loeb 2003

z>6 QSOs with MgII and/or CO redshifts (Walter et al, Willot et al., Maiolino et al., = 0.08 => = 4.4 Mpc

Near-edge of reionization: GP + Cosmic Stromgren Spheres Very Fast? f(HI) > 1e-1 at z >= 6.4 (0.87Gyr) f(HI) < 1e-4 at z <= 5.7 (1.0 Gyr) See also Cosmic Stromgren Surfaces (Mesinger & Haiman 2004)

Gas and dust during the EoR FIR luminous galaxy at z=6.42: 1e13 L sun observe dust, gas, star formation, AGN Merging(?) galaxy: Molecular gas mass = 2x10 10 M _sun, M _dyn = 6e10 M _sun Early enrichment of heavy elements and dust produced in the first stars => star formation commenced at 0.4 Gyr after the big bang Coeval formation of SMBH + stars in earliest galaxies – break-down of M-  at high z? Cosmic Stromgren sphere of 4.7 Mpc => ‘witnessing process of reionization’ t _qso = 1e7 * f(HI) yrs ‘fast’ reionization: f(HI)>0.1 at z=6.4?

J : A second FIR-luminous QSO source at z=6.2 S _250 = 3.0 +/- 0.4 mJy => L _FIR = 7.5e12 L _sun z(MgII)  S(CO 3-2) = / mJy  EVLA correlator: 8GHz, channels z(opt) MAMBO 250 GHzVLA CO 3-2

VLA detections of HCN 1-0 emission n(H _2 ) > 1e5 cm^-3 (vs. CO: n(H _2 ) > 1e3 cm^-3) z=2.58 Solomon et al index=1 z=4.7 z= uJy

Continuum sensitivity of future arrays: Arp 220 vs z (FIR = 1.6e12 L _sun ) cm: Star formation, AGN (sub)mm Dust, molecular gas Near-IR: Stars, ionized gas, AGN ConX: AGN

Studying the pristine IGM beyond the EOR: redshifted HI 21cm observations (100 – 200 MHz) with the Square Kilometer Array. ‘Pathfinders’: LOFAR, MWA, PAST, VLA-VHF,… SKA goal:  Jy at 200 MHz Large scale structure: density, f(HI), T _spin

Low frequency background – hot, confused sky Eberg 408 MHz Image (Haslam ) Coldest regions: T = 100  z)^2.6 K Highly ‘confused’: 3 sources/arcmin^2 with S _0.2 > 0.1 mJy

Terrestrial interference 100 MHz z= MHz z=6

Temperatures: Spin, CMB, Kinetic and the 21cm signal Initially T _S = T _CMB T _S couples to T _K via Lya scattering T _K = (1+z)^2 (wo. heating) T _CMB = 2.73 (1+z) T _S = T _CMB => no signal T _S = T _K Absorption against CMB T _S > T _CMB => Emission T _K T _CMB T _s Tozzi z = 11z = 7  t = 10mK

Global reionization signature in low frequency HI spectra (Gnedin & Shaver 2003) double fast 21cm ‘deviations’ at 1e-4 wrt foreground Spectral index deviations of 0.001

HI 21cm Tomography of IGM Zaldarriaga z=   T _B (2’) = 10’s mK  SKA rms(100hr) = 4mK  LOFAR rms (1000hr) = 80mK

Power spectrum analysis Zaldarriaga LOFAR SKA Z= MHz 2deg 1arcmin

z=3.62 Womble 1996 N(HI) = 1e e15 cm^-2, f(HI/HII) = 1e e-6 => Before reionization N(HI) =1e18 – 1e21 cm^-2 Cosmic Web after reionization = Ly alpha forest (  <= 10)

Cosmic web before reionization: HI 21cm Forest ( Carilli, Gnedin, Owen 2002) Mean optical depth (z = 10) = 1% = ‘Radio Gunn- Peterson effect’ Narrow lines (  = few %, few km/s) = HI 21cm forest (  <= 10), 10/unit z at z=8 Mini-halos (  = 100) (Furlanetto & Loeb 2003) Primordial disks: low cosmic density=0.001/unit z, but high opacity=> fainter radio sources -- GRBs? Radio sources beyond the EOR? Radio loud QSO fraction = 10% to z=5.8 (Petric ) Models => expect 0.05 to 0.5 deg^-2 at z> 6 with S _151 > 6 mJy, out of 100 total (Carlli,Jarvis,Haiman) Z=10 20mJy Z=8

GMRT 228 MHz search for HI21cm abs toward highest z radio galaxy, z=5.2 Continuum point source = 0.55 Jy; rms/(40km/s chan) = 5 mJy z(CO) 230Mhz 8GHz 1” Van Breugel et al.

GMRT 230 MHz z=5.2 channel 20 (229.60MHz)

‘Pathfinders’: PAST, LOFAR, MWA, VLA-VHF, … MWA prototype (MIT/ANU) LOFAR (NL) PAST (CMU/China)VLA-VHF (CfA/NRAO)

VLA-VHF: 180 – 200 MHz Prime focus X-dipole (Greenhill et al – proposed) Leverage: existing telescopes, IF, correlator, operations

Main Experiment: Cosmic Stromgren spheres around z>6 SDSS QSOs (Wyithe & Loeb 2004) VLA spectral/spatial resolution well matched to expected signal: 5’, 1000 km/s VLA-VHF 190MHz 250hrs 15’ 20mK 0.50+/-0.12 mJy

Other Experiments: power spectrum analysis, ‘HI 21cm forest’  Sensitivity per 0.8MHz channel: currently have 16 channels over 12.5 MHz  Piggy-back on CSS experiment  Centrally condensed uv coverage

System/Site characteristics Work hours TV carrier Proposed band First sidelobe = 15db

Challenges and ‘mitigation’: VLA-VHF CSS  Ionospheric phase errors – higher freq (freq^-2); 4deg FoV; 1km B _max  T _bg – higher freq (freq^-2.75)  Confusion (in-beam) – spectral measurement (eg. Morales & Hewitt 2004); mJy point source removal w. A array; precise position and redshift  Wide field problems – polarization, sidelobes, bandpass – all chromatic ?  RFI – “interferometric excision” (but D array); consistently ‘clean’ times in monitor plots (but very insensitive measure) ? Proposed Cost and Timeline  100K in parts (CfA) + labor (CfA/NRAO)  First tests (4 prototypes): Q1, Q  First experiments ( hr): D array, Q  Large proposal (500 hr): D array, Q1 2007

Radio astronomy – Probing the EoR Study physics of the first luminous sources (limited to near-IR to radio wavelengths) Currently limited to pathological systems (‘HLIRGs’) EVLA, ALMA x sensitivity is critical to study normal galaxies Low freq pathfinders: HI 21cm signatures of neutral IGM SKA imaging of IGM z 