ESO Recent Results on Reionization Chris Carilli (NRAO) Dakota/Berkeley,August 2011 CO intensity mapping during reionization: signal in 3 easy steps Recent results on f(HI) at z > 6  Gunn-Peterson overview  Quasar near zones: a new tool  J quasar at z=7.1: the Game Changer  [Lya emission from z=7 LBGs: also in the Game]

Predicted mean CO brightness temperature in 3 simple steps 1.Cosmic star formation rate density required to reionize the IGM using mean baryon density (Haardt & Madau, Bunker et al.)  f esc uv = ionizing photon escape fraction ~ 0.06 (MW), up to 0.2 for z~3 LBGs  C = IGM clumping factor (recombinations) = 5 to 30 (simulations)  Strong increase with z due to increase in mean cosmic baryon density 2. Conversion of star formation rate to IR luminosity based on known properties of galaxies (eg. Kennicutt 1998 and many others)

3. Conversion of IR luminosity to CO luminosity based on known properties of galaxies (‘K-S law’; Daddi et al. 2010)  Roughly linear relationship between L’ CO and L FIR for disk galaxies at low and high z  Similar slope for merger driven starbursts, with different normalization  Disks likely dominate cosmic star formation rate density

Doing some cosmic algebra => mean brightness temperature of CO emission from the galaxies that reionize the neutral IGM at a given redshift [Not what we expect to see at all redshifts, but what is required to have reionization occur at that redshift.] z=8 = 1.1 (0.1/f esc ) -1 (C/5) uK (1+z) 3

Major uncertainties f esc – calibrated with JWST observations of 1 st galaxies C – get handle via HI 21m observations (21cm forest absorption?) Line confusion (30GHz = CO 2-1 z=6.7 or 1-0 at z=2.8): requires dual frequency, cross correlation experiment (eg. 15 and 30GHz). Cross correlation with 21cm will also help (Gong, Visbal) Early production of CO and dust (SFR – FIR – L’CO relationships)

z= km/s +150 km/s 7kpc 1” ~ 5.5kpc CO3-2 VLA ” T B ~ 25K PdBI Early production of dust + CO: detections of 12 quasar host galaxies at z~6 M(dust) ~ 10 8 M o, M(H 2 ) ~ M o SFR – FIR – L’ CO relationships can be calibrated with ALMA/EVLA/JWST observations of representative z>6 galaxy samples.

Gunn-Peterson effect Fan et al 2006 SDSS z~6 quasars Increase of τ GP with z Opaque at z>6 z=

 GP f(HI) (1+z) 3/2  GP > 5 at z>6 => f(HI) > few x Note: saturates at low neutral fraction τ depends on clumping factor and resolution Fan, Carilli, Keating Gunn-Peterson opacity => f(HI)

Local ionization? GP => likely substantial increase in f(HI) at z~6 CMBpol => substantial ionization fraction persisting to z~11

Quasar Near Zones: J Accurate host galaxy redshift from CO: z=6.419 Quasar spectrum => photons leaking down to z=6.32 ‘time bounded’ Stromgren sphere ionized by quasar White et al Difference in z host and z GP => R NZ = 4.7Mpc [f HI L γ t Q ] 1/3 (1+z)

HI Loeb & Barkana HII

Quasar Near-Zones: sample of 28 quasars at z=5.7 to 6.5 Need: z host and z GP GP on-set redshift: empirical approach  Adopt fixed resolution of 20A  Find 1 st point when transmission drops below 10% (of extrapolated) = well above typical GP level.  => Relative, not absolute measurement Wyithe et al z = 6.1

Host galaxy redshifts: CO (12), [CII] (3), MgII (14), UV (8) dz = 0.05 for UV lines dz = 0.01 for MgII dz = for CO, [CII]

Quasar Near-Zones: 28 GP quasars at z=5.7 to 6.5 No correlation of UV luminosity with redshift Correlation of R NZ with UV luminosity R L γ 1/3 L UV

decreases by factor 2.3 from z=5.7 to 6.5 If CSS => f HI increases by factor ~ 10 (eg to ) R NZ = 7.3 – 6.5(z-6) Quasar Near-Zones: R NZ vs redshift [normalized to M 1450 = -27] z>6.15

Alternative hypothesis to Stromgren sphere: Quasar Proximity Zones (Bolton & Wyithe) R NZ measures where density of ionizing photon from quasar > background photons (IGRF) => R NZ [L γ ] 1/2 (1+z) -9/4 Increase in R NZ from z=6.5 to 5.7 is then due to rapid increase in mfp during overlap/ ‘percolation’ stage of reionization Either case (CSS or PZ) => rapid evolution of IGM from z ~ 5.7 to 6.5

ESO Local ionization? QNZ Q-NZ: support substantial increase in f(HI) at z ~ 6 to 7

Breaking news: highest redshift quasar, z=7.1 Clear GP absorption trough: τ > 5 => IGM opaque to Lya How to form 10 9 M o black hole in 750Myr? Mortlock ea. z=6.2, 6.4

z=7.1 quasar near zone Small ~ 2Mpc Continues trend for decreasing NZ size

z=7.1 quasar: Damped Lya profile f(HI)= N(HI)=4e20 cm -2 at 2.6Mpc N(HI) > cm -2 Substantially neutral IGM: f(HI) > 0.1 at 2Mpc distance or Damped Lya galaxy at 2Mpc (probability ~ 5%) (Bolton ea.)

Gunn-Peterson effect Fan et al 2006 z=

ESO Local ionization? QNZ Q-DLA Q-DLA = Best evidence to date for very rapid rise in neutral fraction from z=6 to 7, ie. ‘cosmic phase transition’

CMB large scale polarization   Rules-out high ionization fraction at z > 15  Allows for small (≤ 0.2) ionization to high z  Most action occurs at z ~ 7 to 15  Challenge: systematics extracting large scale signal Dunkley et al. 2008

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LBG galaxies at z=7: Lya spectroscopy Observed increase in fraction of Lya detections of LBG with z

LBG at z=7: fewer detected in Lya than expected Expect 9, detect 3 (two independent samples) => Attenuation of Lya emission by wings of DLA due to neutral IGM or Change in galaxy properties from z=6 to 7 More interlopers than they thought Schenker ea Pentericci ea

Pentericci ea: if drop-off in detections is due to DLA of IGM, modeling => f(HI) > 0.4 at z=7

Local ionization? Q-NZ Q- DLA Cosmic phase transition! Numerous lines of evidence support a very rapid rise in neutral fraction at z ~ 6 to 7 LBG- DLA

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What is the EVLA? similar ten-fold improvement in most areas of cm astronomy frequencies = 1 to 50 GHz 8 GHz BW => 80x old res = 40mas res at 43GHz rms = 6uJy in 1hr at 30GHz What is ALMA? Tenfold improvement (or more), in all areas of (sub)mm astronomy, including resolution, sensitivity, and frequency coverage. antennas: 54x12m, 12x7m antennas frequencies: 80 GHz to 720 GHz res = 20mas res at 700 GHz rms = 13uJy in 1hr at 230GHz ALMA Control Building ALMA+EVLA = Order magnitude improvements from 1GHz to 1 THz!

ALMA Status Antennas, receivers, correlator in production: best submm receivers and antennas ever! Site construction well under way: Observation Support Facility, Array Operations Site, 5 Antenna interferometry at high site! Early science call Q EVLA Status Antenna retrofits 70% complete (100% at ν ≥ 18GHz). Early science in March 2010 using new correlator (2GHz) Full receiver complement completed GHz 5 antennas on high site