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 J1120+0641 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 steps1.Cosmic star formation rate density required to reionize the IGM using mean baryon density (Haardt & Madau, Bunker et al.)

fescuv = 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 LFIR 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.]

<TBsky>z=8 = 1.1 (0.1/fesc)-1 (C/5) uK

(1+z)3

Major uncertainties

• fesc – calibrated with JWST observations of 1st 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=6.42

-150 km/s

+150 km/s

7kpc1” ~ 5.5kpc

CO3-2 VLA

+

0.15” TB ~ 25K

PdBI

Early production of dust + CO: detections of 12 quasar host galaxies at z~6 M(dust) ~ 108Mo, M(H2) ~ 1010 Mo

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 τGP with z

• Opaque at z>6

z=6.4

5.7

6.4

• GP f(HI) (1+z)3/2

• GP > 5 at z>6 => f(HI) > few x 10-3

• 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: J1148+5251

• 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. 2003

Difference in zhost and zGP => RNZ = 4.7Mpc [fHI Lγ tQ]1/3 (1+z)-1

6.32

HI

Loeb & Barkana

HII

Quasar Near-Zones: sample of 28 quasars at z=5.7 to 6.5 • Need: zhost and zGP

• GP on-set redshift: empirical approach Adopt fixed resolution of 20A Find 1st point when transmission drops below 10% (of

extrapolated) = well above typical GP level. => Relative, not absolute measurement

Wyithe et al. 2010

z = 6.1

Host galaxy redshifts: CO (12), [CII] (3), MgII (14), UV (8)

dz = 0.05 for UV linesdz = 0.01 for MgIIdz = 0.003 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 RNZ with UV luminosity

R Lγ1/3

LUV

LUV

<RNZ> decreases by factor 2.3 from z=5.7 to 6.5If CSS => fHI increases by factor ~ 10 (eg. 10-4 to 10-3)

RNZ = 7.3 – 6.5(z-6)

Quasar Near-Zones: RNZ vs redshift [normalized to M1450 = -27]

z>6.15

Alternative hypothesis to Stromgren sphere: Quasar Proximity Zones (Bolton & Wyithe)

• RNZ measures where density of ionizing photon from quasar > background photons (IGRF) =>

RNZ [Lγ]1/2 (1+z)-9/4

• Increase in RNZ 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 109 Mo 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)=0.11.0

0.5

N(HI)=4e20 cm-2 at 2.6Mpc

• N(HI) > 1020.5 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=6.4

5.7

6.4

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

ESO

END

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

ESO

END

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 Q1 2011

EVLA Status

•Antenna retrofits 70% complete (100% at ν ≥ 18GHz).

•Early science in March 2010 using new correlator (2GHz)

•Full receiver complement completed 2012 + 8GHz

5 antennas on high site