Radio astronomical probes of Cosmic Reionization and the 1st luminous objects

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Radio astronomical probes of Cosmic Reionization
and the 1st luminous objects Chris Carilli, NRL,
April 2008

• Brief introduction to cosmic reionization
• Objects within reionization recent observations
  of molecular gas, dust, and star formation, in
  the host galaxies of the most distant QSOs early
  massive galaxy and SMBH formation
• Neutral Intergalactic Medium (IGM) HI 21cm
  telescopes, signals, and challenges

USA Carilli, Wang, Wagg, Fan, Strauss Euro
Walter, Bertoldi, Cox, Menten, Neri, Omont
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Ionized
Neutral
Reionized
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Chris Carilli (NRAO) Berlin June 29, 2005
WMAP structure from the big bang
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Hubble Space Telescope Realm of the Galaxies
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Dark Ages

• Last phase of cosmic evolution to be tested
• Bench-mark in cosmic
• structure formation
• indicating the first
• luminous structures

Cosmic Reionization
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Constraint I Gunn-Peterson Effect
z
Barkana and Loeb 2001
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Constraint I Gunn-Peterson Effect

• End of reionization?
• f(HI) lt1e-4 at z 5.7
• f(HI) gt1e-3 at z 6.3

Fan et al 2006
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Constraint II CMB large scale polarization --
Thomson scattering during reionization

• Scattering CMB local quadrapole gt polarized
• Large scale horizon scale at reioniz 10s deg
• Signal is weak
• TE 10 TT
• EE 1 TT

Hinshaw et al 2008
?e 0.084 /- 0.016 l/mfp l ne ?e ?(1z)2
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Constraint II CMB large scale polarization --
Thomson scattering during reionization

• Rules-out high ionization fraction at zgt 15
• Allows for finite (0.2) ionization to high z
• Most action occurs at z 8 to 14

Dunkley et al. 2008
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Fan, Carilli, Keating ARAA 06
GP gt First light occurs in twilight zone,
opaque for ?obs lt0.9 ?m

• GP gt pushing into near-edge of reionization at z
  6
• CMB pol gt substantial ionization fraction
  persists to z 11

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Radio observations of z 6 QSO host galaxies

• 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, C
• VLA uJy sens at 1.4 GHz ? star formation
• VLA lt 0.1 mJy sens at 20-50 GHz 0.2 resol.
  ? mol. gas (low order)

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Why QSOs?

• Spectroscopic redshifts
• Extreme (massive) systems
• MB lt -26 gt
• Lbol gt 1e14 Lo
• MBH gt 1e9 Mo
• Rapidly increasing samples
• zgt4 gt 1000 known
• zgt5 gt 100
• zgt6 20

Fan 05

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Magorrian, Tremaine, Gebhardt, Merritt
QSO host galaxies MBH -- Mbulge relation

• Most (all?) low z spheroidal galaxies have SMBH
  MBH0.002 Mbulge
• Causal connection between SMBH and spheroidal
  galaxy formation
• Luminous high z QSOs have massive host galaxies
  (1e12 Mo)

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MAMBO surveys of zgt2 QSOs
2.4mJy

• 1/3 of luminous QSOs have S250 gt 2 mJy,
  independent of redshift from z1.5 to 6.4
• LFIR 1e13 Lo 0.1 x Lbol Dust heating by
  starburst or AGN?

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Dust gt Gas LFIR vs L(CO)
z 6 QSO hosts
Star formation
1e3 Mo/yr
Index1.5
1e11 Mo
Gas Mass

• non-linear gt increasing SF eff (SFR/Gas mass)
  with increasing SFR
• FIR-luminous high z QSO hosts have massive gas
  reservoirs (gt1e10 Mo) fuel for star formation

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Pushing into reionization QSO 114852 at z6.4

• Highest redshift SDSS QSO (tuniv 0.87Gyr)
• Lbol 1e14 Lo
• Black hole 3 x 109 Mo (Willot etal.)
• Gunn Peterson trough (Fan etal.)

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• 114852 z6.42 Dust detection

MAMBO 250 GHz
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S250 5.0 /- 0.6 mJy LFIR 1.2e13 Lo Mdust
7e8 Mo

• Dust formation?
• AGB Winds 1.4e9yr gt tuniv 0.87e9yr
• gt dust formation associated with high mass star
  formation Silicate gains (vs. eg. Graphite)
  formed in core collapse SNe (Maiolino 07)?

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11485251 Radio to near-IR SED
TD 50 K
Elvis SED
Radio-FIR correlation

• FIR excess 50K dust
• Radio-FIR SED follows star forming galaxy
• SFR 3000 Mo/yr

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114852 z6.42 Gas detection
VLA
IRAM

• FWHM 305 km/s
• z 6.419 /- 0.001
• M(H2) 2e10 Mo
• Mgas/Mdust 30 ( starburst galaxies)

VLA
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CO excitation ladder
?2
NGC253
Dense, warm gas CO excitation similar to
starburst nucleus Tkin gt 80 K nH2 1e5 cm-3
MW
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J114852 VLA imaging of CO3-2
0.4res
rms50uJy at 47GHz
1
0.15 res

• Separation 0.3 1.7 kpc
• TB 35K gt Typical of starburst nuclei, but
  scale is 10x larger

CO extended to NW by 1 (5.5 kpc)
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CII 158um fine structure line dominant ISM gas
cooling line
CII traces PDRs associated with star formation
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CII 158um at z6.4

• zgt4 gt FS lines redshift to mm band
• LCII 4x109 Lo (LNII lt 0.1 LCII)
• CII similar extension as molecular gas 6kpc
  gt distributed star formation
• SFR 6.5e-6 LCII 3000 Mo/yr

IRAM 30m
CII
NII
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CII PdBI Walter et al.
CII CO 3-2
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Gas dynamics Potential for testing MBH - Mbulge
relation at high z -- mm lines are only direct
probe of host galaxies
Mdyn 4e10 Mo Mgas 2e10 Mo Mbh 3e9 Mo
gt Mbulge 1e12 Mo (predicted)
11485251 z6.42
zlt0.5
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FIR - Lbol in QSO hosts
Z6
Low z IR QSOs major mergers AGNstarburst?
Low z Optical QSOs early-type hosts
Wang 08, Hao 07
FIR luminous z 6 QSO hosts follow relation
establish by IR-selected QSOs at low z gt (very)
active star forming host galaxies?
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Downsizing Building a giant elliptical galaxy
SMBH at tuniv lt 1Gyr
z10
10.5
Li, Hernquist, Roberston..

• Multi-scale simulation isolating most massive
  halo in 3 Gpc3 (co-mov)
• Stellar mass 1e12 Mo forms in series (7) of
  major, gas rich mergers from z14, with SFR 1e3
  - 1e4 Mo/yr
• SMBH of 2e9 Mo forms via Eddington-limited
  accretion mergers
• Evolves into giant elliptical galaxy in massive
  cluster (3e15 Mo) by z0

8.1
6.5

• Rapid enrichment of metals, dust, molecules
• Rare, extreme mass objects 100 SDSS z6 QSOs
  on entire sky
• Integration times of hours to days to detect
  HyLIGRs

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SMA
The need for collecting area lines
cm telescopes low order molecular transitions --
total gas mass, dense gas tracers
, GBT
(sub)mm high order molecular lines. fine
structure lines -- ISM physics, dynamics

• FS lines will be workhorse lines in the study of
  the first galaxies with ALMA.
• Study of molecular gas in first galaxies will be
  done primarily with cm telescopes

ALMA will detect dust, molecular and FS lines in
1 hr in normal galaxies (SFR 10 Mo/yr
LBGs, LAEs) at z 6, and derive z directly from
mm lines.
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The need for collecting area continuum A
Panchromatic view of galaxy formation
Arp 220 vs z
SMA
cm Star formation, AGN
(sub)mm Dust, molecular gas
Near-IR Stars, ionized gas, AGN
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Cosmic Stromgren Sphere

• Accurate host redshift from CO z6.419/0.001
• Ly a, high ioniz lines inaccurate redshifts (?z
  gt 0.03)
• Proximity effect photons leaking from
  6.32ltzlt6.419

White et al. 2003
z6.32

• time bounded Stromgren sphere R 4.7 Mpc
• tqso 1e5 R3 f(HI) 1e7yrs
• or
• f(HI) 1 (tqso/1e7 yr)

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Loeb Rybicki 2000
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CSS Constraints on neutral fraction at z6

• Nine z6 QSOs with CO or MgII redshifts ltRgt
  4.4 Mpc
• GP gt f(HI) gt 0.001
• If f(HI) 0.001, then lttqsogt 1e4 yrs
  implausibly short given QSO fiducial lifetimes
  (1e7 years)?
• Probability arguments size evolution suggest
  f(HI) gt 0.05

Wyithe et al. 2005
Fan et al 2006
P(gtxHI)
90 probability x(HI) gt curve
tqso/4e7 yrs
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Fan, Carilli, Keating ARAA 2006

• Not event but complex process, large
  variance zreion 14 to 6
• Good evidence for qualitative change in nature
  of IGM at z6

ESO
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Local ioniz.?

• Current probes are all fundamentally limited in
  diagnostic power
• Need more direct probe of process of reionization

ESO
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Studying the pristine neutral IGM using
redshifted HI 21cm observations (100 200 MHz)

• Large scale structure
• cosmic density, ?
• neutral fraction, f(HI)
• Temp TK, TCMB, Tspin

1e13 Mo
1e9 Mo
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Experiments under-way pathfinders 1 to 10 SKA
LOFAR (NL)
MWA (MIT/CfA/ANU)
SKA
21CMA (China)
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Signal I HI 21cm Tomography of IGM Furlanetto,
Zaldarriaga 2004
z12
9

• ?TB(2) 10s mK
• SKA rms(100hr) 4mK
• LOFAR rms (1000hr) 80mK

7.6
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Signal II 3D Power spectrum analysis
? only
LOFAR
? f(HI)
SKA
McQuinn 06
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Signal III Cosmic Web after reionization Ly
alpha forest at z3.6 (? lt 10)
Womble 96

• N(HI) 1e13 1e15 cm-2, f(HI/HII) 1e-5 --
  1e-6 gt before reionization N(HI) 1e18 1e21
  cm-2
• ?Lya 1e7 ?21cm gt neutral IGM opaque to Lya,
  but translucent to 21cm

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Signal III Cosmic web before reionization HI
21Forest
z12
z8
19mJy
130MHz
159MHz

• Perhaps easiest to detect
• Only probe of small scale structure
• Requires radio sources expect 0.05 to 0.5
  deg-2 at zgt 6 with S151 gt 6 mJy?

• radio G-P (?1)
• 21 Forest (10)
• mini-halos (10)
• primordial disks (100)

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Signal IV Cosmic Stromgren spheres around z gt 6
QSOs

• LOFAR observation
• 20xf(HI)mK, 15,1000km/s
• gt 0.5 x f(HI) mJy
• Pathfinders Set first hard limits on f(HI) at
  end of cosmic reionization

5Mpc
Wyithe et al. 2006
Prediction first detection of HI 21cm signal
from reionization will be via imaging rare,
largest CSS, or absorption toward radio galaxy.
0.5 mJy
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Challenge I Low frequency foreground hot,
confused sky Eberg 408 MHz Image (Haslam 1982)
Coldest regions T 100 (?/200 MHz)-2.6
K Highly confused 1 source/deg2 with S140 gt 1
Jy
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• Solution spectral decomposition (eg. Morales,
  Gnedin)
• Foreground non-thermal featureless over
  100s MHz
• Signal fine scale structure on scales few MHz

Cygnus A
500MHz
5000MHz

• Simply remove low order polynomial or other
  smooth function
• Xcorr/power spectral analysis in 3D different
  symmetries in freq

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Challenge II Ionospheric phase errors varying
e- content

• TIDs fuzz-out sources
• Isoplanatic patch few deg few km
• Phase variation proportional to ?2
• Solution
• Reionization requires only short baselines (lt
  1km)
• Wide field rubber screen phase self-calibration

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Virgo A VLA 74 MHz Lane 02
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Challenge III Interference
100 MHz z13
200 MHz z6

• Solutions -- RFI Mitigation (Ellingson06)
• Digital filtering
• Beam nulling
• Real-time reference beam
• LOCATION!

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VLA-VHF 180 200 MHz Prime focus X-dipole
Greenhill, Blundell (SAO) Carilli, Perley (NRAO)
Leverage existing telescopes, IF, correlator,
operations

• 110K DD/construction (CfA)
• First light Feb 16, 05
• Four element interferometry May 05
• First limits Winter 06/07

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Project abandoned Digital TV
KNMD Ch 9 150W at 100km
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RFI mitigation location, location location
100 people km-2
1 km-2
0.01 km-2
Chippendale Beresford 2007
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C.Carilli, A. Datta (NRAO/SOC), J. Aguirre
(U.Penn)

• Focus Reionization (power spec,CSS,abs)
• Very wide field 30deg
• Correlator FPGA-based from Berkeley wireless
  lab
• Staged engineering approach GB05 8 stations ?
  Boolardy08 32 stations

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PAPER Staged Engineering

• Broad band sleeve dipole flaps
• 8 dipole test array in GB (06/07) gt 32 station
  array in WA (2008) to 256 (2009)
• FPGA-based pocket correlator from Berkeley
  wireless lab
• S/W Imaging, calibration, PS analysis AIPY
  Miriad/AIPS gt Python CASA, including
  ionospheric peeling calibration

100MHz
200MHz
BEE2 5 FPGAs, 500 Gops/s
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PAPER/WA -- 4 Ant, July 2007 RMS 1Jy DNR 1e4
1e4Jy
Parsons et al. 2008
CygA 1e4Jy
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Radio astronomy probing cosmic reionization

• Twilight zone obs of 1st luminous sources
  limited to near-IR to radio wavelengths
• Currently -- pathological systems (HLIRGs)
  coeval formation SMBHgiant ellipt. in
  spectacular starburst at tunivlt1Gyr
• EVLA, ALMA 10-100x sensitivity is critical to
  study normal galaxies
• Low freq pathfinders HI 21cm signatures of
  neutral IGM
• SKA imaging of IGM

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END
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Stratta, Maiolino et al. 2006 extinction toward
z6.2 QSO and 6.3 GRB gt Silicate amorphous
Carbon dust grains (vs. eg. Graphite) formed in
core collapse SNe?
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Sources responsible for reionization

• Luminous AGN No
• Star forming galaxies maybe -- dwarf galaxies
  (Bowens05 Yan04)?
• mini-QSOs -- unlikely (soft Xray BG Dijkstra04)
• Decaying sterile neutrinos -- unlikely (various
  BGs Mapelli05)
• Pop III stars zgt10? midIR BG (Kashlinsky05),
  but trecomb lt tuniv at z10
• GP gt Reionization occurs in twilight zone,
  opaque for ?obs lt0.9 ?m

Needed for reion.
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GMRT 230 MHz HI 21cm abs toward highest z
radio galaxy and QSO (z5.2)
RFI 20 kiloJy !
232MHz 30mJy
229Mhz 0.5 Jy
rms(40km/s) 3mJy
rms(20km/s) 5 mJy
N(HI) 2e20TS cm-2 ?
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Building a giant elliptical galaxy SMBH by z6.4
Mstars1e12Mo
MBH 2e9Mo

• Enrichment of heavy elements, dust starts early
  (z gt 8)
• Rare, extreme mass objects 100 SDSS z6 QSOs
  on entire sky
• Integration times of hours to days to detect
  HyLIGRs

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Destination Moon!

• No interference
• No ionosphere
• Only place to study PGM

RAE2 1973

• Recognized as top astronomy priority for NASA
  initiative to return Man to Moon (Livio 2007)
• NASA concept study DALI/LAMA (NRL MIT )

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• Limitations of measurements
• CMB polarization
• ??e integral measure through universe gt
  allows many reionization scenarios
• Difficult measurement (10s degrees, uK) result

• Gunn-Peterson effect
• ?Lya to f(HI) conversion requires clumping
  factor (cf. Becker etal 06)
• ?Lya gtgt1 for f(HI)gt0.001 gt low f(??) diagnostic
• GP gt First light occurs in twilight zone,
  opaque for ?obs lt0.9 ?m

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CII -- the good and the bad

• CII/FIR decreases rapidly with LFIR (lower
  heating efficiency due to charged dust grains?)
  gt luminous starbursts are still difficult to
  detect in C
• Normal star forming galaxies (eg. LAEs) are not
  much harder to detect!

J1623
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Signal I Global (all sky) reionization
signature
Signal 20mK lt 1e-4 sky
Feedback in Galaxy formation No Feedback
Possible higher z absorption signal via Lya
coupling of Ts -- TK due to first luminous
objects
Furlanetto, Oh, Briggs 06