Download Heidelberg, July 2005

F(HI) = 0
History of IGM
C.Carilli (NRAO) Heidelberg 05
F(HI) = 1
Epoch of
Reionization (EoR)
•last phase of cosmic
evolution to be tested
F(HI) = 1e-5
•bench-mark in cosmic
structure formation
indicating the first
luminous structures
The Gunn Peterson Effect
z=5.80
End of reionization
f(HI) > 0.001 at z = 6.3
=> opaque at l_obs<0.9mm
z=5.82
z=5.99
z=6.28
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 + 2005; White + 2005
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
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
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)>0.001
-- High z universe is opaque at (observed) optical
wavelengths
 Reionization occurs in ‘twilight zone’, observable at
near-IR through radio wavelengths
Radio astronomical probes of the Epoch of Reionization and
the 1st luminous objects
1. CMB: large scale polarization + secondary anisotropies
2. Objects within EoR – Molecular gas, dust, star
formation, process of reionization
3. 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)
http://www.skatelescope.org/pages/page_astronom.htm
 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 20-50 GHz +
0.2” resol.  mol. gas (low order)
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
Radio-FIR (Yun+ 02)
SFR = 1e3 x S_250 M_sun/yr
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
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)
MAMBO surveys of z>2 DPSS+SDSS QSOs
1148+52 z=6.4
1e13L_sun
1048+46 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?
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
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
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.)
Cosmic (proper) time
1/16 T_univ = 0.87Gyr
1148+52 z=6.42: Dust and Gas detection
L_FIR = 1.2e13 L_sun, M_dust =7e8M_sun
M(H_2) = 2e10 M_sun
46.6149 GHz
CO 3-2
S_250 = 5.0 +/- 0.6 mJy
Off channels
Rms=60uJy
• 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)?
IRAM Plateau de Bure
n2
(6-5)
(7-6)
(3-2)
• FWHM = 305 km/s
• z = 6.419 +/- 0.001
• Tkin=100K, nH2=105cm-3
 Typical of starburst nuclei (eg.
NGC253, Arp220)
VLA imaging of CO3-2 at 0.4” and 0.15” resolution
rms=50uJy at 47GHz
 CO extended to NW by 1”
(=5.5 kpc) tidal(?) feature
 Separation = 0.3” = 1.7 kpc
 T_B = 20K  Typical of
starburst nuclei
Merging galaxies?
1148+5251: radio-FIR SED
S_1.4= 55 +/- 12 uJy
Beelen et al.
T_D = 50 K
1048+46
 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 ?
1148+52: 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?]
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
Loeb & Rybicki 2000
z>6 QSOs with MgII and/or CO redshifts (Wyithe et al. 05)
<Dz> = 0.08 => <R> = 4.4 Mpc
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
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)
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?
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
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
Low frequency background – hot, confused sky
Eberg 408 MHz Image (Haslam + 1982)
Coldest regions: T = 100 (n/200 MHz)^-2.6 K
Highly ‘confused’: 3 sources/arcmin^2 with S_0.2 > 0.1 mJy
Interference
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
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
HI 21cm Tomography of IGM
Zaldarriaga + 2003
z=12
9
DT_B(2’) = 10’s mK
SKA rms(100hr) = 4mK
LOFAR rms (1000hr) = 80mK
7.6
Power spectrum analysis
Zaldarriaga + 2003
Z=10
129 MHz
LOFAR
SKA
2deg
1arcmin
Cosmic Web after reionization = Ly alpha forest (d <= 10) 1422+23
z=3.62 Womble 1996
N(HI) = 1e13 -- 1e15 cm^-2, f(HI/HII) = 1e-5 -- 1e-6
=> Before reionization N(HI) =1e18 – 1e21 cm^-2
Cosmic web before reionization: HI 21Forest
• radio G-P (t=1%)
z=12
20mJy
z=8
• 21 Forest (10%)
• mini-halos (10%)
• primordial disks (100%)
130MHz
• expect 0.05 to 0.5 deg^-2
at z> 6 with S_151 > 6 mJy
(Carlli,Jarvis,Haiman)
‘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, 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
Main Experiment: Cosmic Stromgren spheres around
z=6 to 6.5 SDSS QSOs (Wyithe & Loeb 2004)
20 f(HI) mK
VLA-VHF
190MHz
250hrs
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
Other Experiments: power spectrum analysis, ‘HI 21cm forest’
2deg

System characteristics
First sidelobe = 14% (goal < 5%)
Efficiency = 28% (goal: 50%)
 Xpol = 20% (goal: 5%)
4deg
T_sys = 50 (Rx) + 150 (sky) K
FoV = 12 deg^2
rms/chan= 0.12mJy in 250 hrs (goal)
Correlator: 0.8MHz/chan, 16 chan, 2 pol.
3C313 --first
image
Main hurdle: Interference!
KNMD Ch 9
Digital TV
Digital TV: 186 to 192MHz,
200 W from ABQ
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 10-100x
sensitivity is critical to
study normal galaxies
•Low freq pathfinders:
HI 21cm signatures of
neutral IGM
•SKA imaging of IGM
z=6.4
PKS 2322+1944 z=4.12: [CI] (492 GHz rest freq; Pety et al.)
VLA CO2-1
PdBI
=> Solar Metalicity
GMRT 228 MHz – HI 21cm abs toward
highest z radio galaxy, 0924-220 z=5.2
RFI = 20 kiloJy !
8GHz
1”
Van Breugel et al.
rms/(40km/s chan) = 5 mJy
230Mhz
point source = 0.55 Jy;
z(CO)
Richards et al. 2002
SDSS QSOs
1000km/s => Dz = 0.03
J1048+4637: A second FIR-luminous QSO
source at z=6.2
VLA CO(3-2)
S_250 = 3.0 +/- 0.4 mJy=> L_FIR=7.5e12 L_sun
GBT/EVLA/ALMA/LMT correlator:
8–32 GHz, 16000 channels
z(opt)
z(MgII)
Gunn-Peterson effect
Barkana and Loeb 2001
Complex reionization example: Double reionization? (Cen 2002;
cf. Furlanetto, Gnedin,…)
‘normal’ galaxies
(>1e8M_sun)
Pop III stars in
‘mini-halos’
(<1e7 M_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