1. C.Carilli (NRAO) Heidelberg 05
History of IGM
F(HI) = 0
C.Carilli (NRAO) Heidelberg 05
F(HI) = 1
Epoch of
Reionization (EoR)
last phase of cosmic evolution to be tested
bench-mark in cosmic
structure formation
indicating the first
luminous structures
F(HI) = 1e-5

2. => opaque at l_obs<0.9mm
The Gunn Peterson Effect
z=5.80
z=5.82
z=5.99
z=6.28
End of reionization f(HI) > at z = 6.3
=> opaque at l_obs<0.9mm
Fan et al 2003

3. Near-edge of reionization: GP Effect
Fairly Fast:
f(HI) > 1e-3 at z >= 6.3 (0.87Gyr)
f(HI) < 1e-4 at z <= 5.7 (1.0 Gyr)
Although cf. Songaila, Oh, Stern, Malhotra…
Fan ; White

4. Normalization: GP absorption, LCDM + z=4 LBGs, T_IGM
Neutral IGM evolution (Gnedin 2004): ‘Cosmic Phase transition’ at z=6 to 7
8 Mpc (comoving)
Normalization: GP absorption, LCDM + z=4 LBGs, T_IGM

5. WMAP Large scale polarization of CMB (Kogut et al.)
CMB Temperature fluctuations imprinted by primordial density fluctuations at last scattering (z=1000)
Large scale polarization: Thompson scattering at EoR
t_e = 0.17 =>
F(HI) < 0.5 at z=17
20deg

6. GP + CMB => ‘complex’ reionization extending from z=20 to 6?
Limitations of current measurements:
CMB polarization: -- t_e = Ln_es_e = integral measure through universe => allows many reionization scenarios
Gunn-Peterson effect: -- t_Lya >>1 for f(HI)> High z universe is opaque at (observed) optical wavelengths
 Reionization occurs in ‘twilight zone’, observable at near-IR through radio wavelengths

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

8. IRAM 30m + MAMBO: sub-mJy sens at 250 GHz + wide fields  dust
IRAM PdBI: sub-mJy sens at 90 and 230 GHz + arcsec resol. mol. gas
VLA: uJy sens at 1.4 GHz  star formation
VLA: < 0.1 mJy sens at GHz + 0.2” resol.  mol. gas (low order)

9. L_FIR = 4e12 x S_250(mJy) L_sun SFR = 1e3 x S_250 M_sun/yr
FIR = 1.6e12 L_sun
Magic of (sub)mm: distance independent method of studying objects in universe for z=0.8 to 8
L_FIR = 4e12 x S_250(mJy) L_sun
SFR = 1e3 x S_250 M_sun/yr
Radio-FIR (Yun+ 02)

10. High Redshift QSOs: SDSS, DPSS (Fan 2005)
z>4: 950 known
z>5: 52
z>6: 8
30 at z~6 expected in the whole survey
M_B < -26 =>
L_bol > 1e14 L_sun
M_BH > 1e9 M_sun

11. QSO host galaxies – M_BH – s relation
Most (all?) low z spheroidal galaxies have SMBH: M_BH=0.002M_bulge
‘Causal connection between SMBH and spheroidal galaxy formation’ (Gebhardt et al. 2002)?
Luminous high z QSOs have massive host galaxies (1e12 M_sun)

12. MAMBO surveys of z>2 DPSS+SDSS QSOs
1e13L_sun
z=6.2
Arp220
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?

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

14. VLA detections of HCN 1-0 emission
n(H_2) > 1e5 cm^-3 (vs. CO: n(H_2) > 1e3 cm^-3)
index=1
Solomon et al
z=2.58
70 uJy

15. Objects within EoR: QSO 1148+52 at z=6.4
highest redshift quasar known
L_bol = 1e14 L_sun
central black hole: 1-5 x 109 Msun (Willot etal.)
clear Gunn Peterson trough (Fan etal.)

16. Cosmic (proper) time
1/16 T_univ = 0.87Gyr

17. 1148+52 z=6.42: Dust and Gas detection
M(H_2) = 2e10 M_sun
L_FIR = 1.2e13 L_sun, M_dust =7e8M_sun
Off channels
Rms=60uJy
GHz
CO 3-2
S_250 = 5.0 +/- 0.6 mJy
Dust formation: 1.4e9yr (AGB winds) > t_univ (8.7e8yr) => dust formed in high mass stars? => silicate grains?
C, O production (3e7 M_sun): few e8 yr => Star formation started early (z = 10)?

18.  Typical of starburst nuclei (eg. NGC253, Arp220)
IRAM Plateau de Bure n2
(6-5)
(7-6)
(3-2)
Tkin=100K, nH2=105cm-3
FWHM = 305 km/s
z = /
 Typical of starburst nuclei (eg. NGC253, Arp220)

19. VLA imaging of CO3-2 at 0.4” and 0.15” resolution
rms=50uJy at 47GHz
Separation = 0.3” = 1.7 kpc
T_B = 20K  Typical of starburst nuclei
Merging galaxies?
CO extended to NW by 1” (=5.5 kpc) tidal(?) feature

20. Stellar spheroid formation in few e7 yrs = e-folding time for SMBH
: radio-FIR SED
Beelen et al.
S_1.4= 55 +/- 12 uJy
T_D = 50 K
Star forming galaxy characteristics: radio-FIR SED, Gas/Dust, CO excitation and T_B => Coeval starburst/AGN? SFR = 1e3 M_sun/yr
Stellar spheroid formation in few e7 yrs = e-folding time for SMBH
=> Coeval formation of galaxy/SMBH at z = 6.4 ?

21. M_BH = 3e9 M_sun => M_bulge = 1.5e12 M_sun
: Masses
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 – s breaks-down at high z? [SMBH forms first?]

22. Cosmic Stromgren Sphere
Accurate redshift from CO: z=6.419+/0.001
Ly a, high ioniz Lines: inaccurate redshifts (Dz > 0.03)
Proximity effect: photons leaking from 6.32<z<6.419
White et al. 2003
z=6.32
‘time bounded’ Stromgren sphere: R = 4.7 Mpc
t_qso= 1e5 R^3 f(HI)= 1e7yrs

23. Loeb & Rybicki 2000

24. <Dz> = 0.08 => <R> = 4.4 Mpc
z>6 QSOs with MgII and/or CO redshifts (Wyithe et al. 05)
<Dz> = 0.08 => <R> = 4.4 Mpc

25. Constraints on neutral fraction at z=6.4 ?
GP => f(HI) > 0.001
If f(HI) = 0.001, then t_qso = 1e4 yrs – implausibly short given QSO fiducial lifetimes (1e7 years)?
Probability arguments suggest: f(HI) > 0.1
P(>x_HI)
10%
Wyithe et al. 2005
90% probability
x(HI) > curve
t_qso/1e7 yrs

26. 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 but cf. Oh & Furnaletto 2005)

27. Molecular Gas and dust during the EoR
FIR luminous galaxy at z=6.42: 1e13 Lsun observe dust, gas, star formation, AGN
Sub-kpc imaging: Merging galaxy: M_gas= 2x1010 M_sun, M_dyn=6e10 M_sun
Early enrichment of heavy elements and dust produced => star formation 0.4 Gyr after the big bang
High z: Coeval formation of SMBH + stars and break-down of M-s at high z?
Cosmic Stromgren sphere = 4.7 Mpc =>
‘witnessing process of reionization’
t_qso = 1e7 * f(HI) yrs
‘fast’ reionization: f(HI)>0.1 at z=6.4?

28. (sub)mm: Dust, molecular gas Near-IR: Stars, ionized gas, AGN
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

29. 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: mJy at 200 MHz
Large scale structure: density, f(HI), T_spin

30. Low frequency background – hot, confused sky
Eberg 408 MHz Image (Haslam )
Coldest regions: T = 100 (n/200 MHz)^-2.6 K
Highly ‘confused’: 3 sources/arcmin^2 with S_0.2 > 0.1 mJy

31. Interference Ionospheric phase errors TIDs – ‘fuzz-out’ sources
100 MHz z=13
200 MHz z=6
Ionospheric phase errors
TIDs – ‘fuzz-out’ sources
‘Isoplanatic patch’ = few deg = few km
Phase variation proportional to wavelength^2
74MHz Lane 03

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

33. HI 21cm Tomography of IGM Zaldarriaga + 20039
7.6
DT_B(2’) = 10’s mK
SKA rms(100hr) = 4mK
LOFAR rms (1000hr) = 80mK

34. Power spectrum analysis
Zaldarriaga
Z=10
129 MHz
LOFAR
SKA
2deg
1arcmin

35. Cosmic web before reionization: HI 21Forest
Cosmic Web after reionization = Ly alpha forest (d <= 10) 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 before reionization: HI 21Forest
radio G-P (t=1%)
21 Forest (10%)
mini-halos (10%)
primordial disks (100%)
expect 0.05 to 0.5 deg^-2 at z> 6 with S_151 > 6 mJy (Carlli,Jarvis,Haiman)
z=12
z=8
20mJy
130MHz

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

37. Leverage: existing telescopes, IF, correlator, operations
VLA-VHF: 180 – 200 MHz Prime focus X-dipole Greenhill, Blundell (SAO Rx lab); Carilli, Perley (NRAO)
Leverage: existing telescopes, IF, correlator, operations
$110K D+D/construction (CfA)
First light: Feb 16, 05
Four element interferometry: May 05
First limits: Dec 05

38. Main Experiment: Cosmic Stromgren spheres around z=6 to 6
Main Experiment: Cosmic Stromgren spheres around z=6 to 6.5 SDSS QSOs (Wyithe & Loeb 2004)
VLA-VHF 190MHz 250hrs
20 f(HI) mK
15’
VLA spectral/spatial resolution well matched to expected signal: 7’, 1000 km/s
Set first hard limits on f(HI) at end of cosmic reionization (f(HI) < 0.3)
Easily rule-out cold IGM (T_s < T_cmb): signal = 360 mK
0.50+/-0.12 mJy

39. Other Experiments: power spectrum analysis, ‘HI 21cm forest’
2deg

40. System characteristics
First sidelobe = 14% (goal < 5%)
Efficiency = 28% (goal: 50%)
Xpol = 20% (goal: 5%)
T_sys = 50 (Rx) (sky) K
FoV = 12 deg^2
rms/chan= 0.12mJy in 250 hrs (goal)
Correlator: 0.8MHz/chan, 16 chan, 2 pol.
4deg
3C313 --first
image

41. Main hurdle: Interference! Digital TV: 186 to 192MHz, 200 W from ABQ
KNMD Ch 9 Digital TV

42. Radio astronomy – Probing the EoR
‘Twilight zone’:physics of 1st 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=6.4

43. => Solar Metalicity
PKS z=4.12: [CI] (492 GHz rest freq; Pety et al.)
VLA CO2-1
PdBI
=> Solar Metalicity

44. GMRT 228 MHz – HI 21cm abs toward highest z radio galaxy, 0924-220 z=5
RFI = 20 kiloJy !
8GHz 1”
Van Breugel et al.
rms/(40km/s chan) = 5 mJy
230Mhz
point source = 0.55 Jy;
z(CO)

45. Richards et al. 2002
SDSS QSOs
1000km/s => Dz = 0.03

46. J1048+4637: A second FIR-luminous QSO source at z=6.2
S_250 = 3.0 +/- 0.4 mJy=> L_FIR=7.5e12 L_sun
VLA CO(3-2)
z(opt)
z(MgII)
GBT/EVLA/ALMA/LMT correlator: 8–32 GHz, channels

47. Gunn-Peterson effect
Barkana and Loeb 2001

48. Complex reionization example: Double reionization. (Cen 2002; cf
Complex reionization example: Double reionization? (Cen 2002; cf. Furlanetto, Gnedin,…)
Pop III stars in ‘mini-halos’ (<1e7 M_sun)
‘normal’ galaxies (>1e8M_sun)
Recombination time < hubble time at z > 8
Stellar fusion produces 7e6eV/H atom, reionization requires 13.6eV/H atom =>Need to process only 1e-5 of baryons through stars to reionize the universe