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Radio astronomical probes of Cosmic Reionization and the 1 st luminous objects Chris Carilli March 19, 2007 University of Colorado. Brief introduction to cosmic reionization

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

Chris Carilli March 19, 2007 University of Colorado

  • 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, and more…

  • Neutral Intergalactic Medium (IGM) – HI 21cm telescopes, signals, and challenges

USA – Carilli, Wang, Fan, Strauss, Gnedin

Euro – Walter, Bertoldi, Cox, Menten, Omont


Ionized

Neutral

Reionized


Chris Carilli (NRAO)

Berlin June 29, 2005

WMAP – structure from the big bang



Dark Ages

Epoch of Reionization

Twilight Zone

  • Last phase of cosmic evolution to be tested

  • Bench-mark in cosmic

    structure formation

    indicating the first

    luminous structures


Constraint I: Gunn-Peterson Effect

  • End of reionization?

  • f(HI) <1e-4 at z= 5.7

  • f(HI) >1e-3 at z= 6.3

Fan et al 2006


Constraint II: CMB large scale polarization -- Thompson scattering during reionization

Page + 06; Spergel 06

TT

  • Scattered CMB quad. => polarized

  • Horizon scale => 10’s deg

  • e = 0.09+/-0.03

  • z_reion= 11+/3

TE

EE


Fan, Carilli, Keating ARAA 06

Gnedin03

8Mpc

  • Current observations => zreion = 6 to 11 (+/-3)?

  • Not ‘event’ but complex process, large variance time/space (eg. Shull & Venkatesan 2006)


Limitations of measurements

CMB polarization

  • e = integral measure through universe => allows many reionization scenarios

  • Still a 3 result (now in EE vs. TE before)

Gunn-Peterson effect

  • Lya to f(HI) conversion requires ‘clumping factor’ (cf. Becker etal 06)

  • Lya >>1 for f(HI)>0.001 => low f() diagnostic

    GP => Reionization occurs in ‘twilight zone’, opaque for obs <0.9 m


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: < 0.1 mJy sens at 20-50 GHz + 0.2” resol.  mol. gas (low order)


Magic of (sub)mm: distance independent method of studying objects in universe from z=0.8 to 10

L_FIR ~ 4e12 x S250(mJy) L_sun

SFR ~ 1e3 x S250 M_sun/yr

FIR = 1.6e12 L_sun


Why QSOs? objects in universe from z=0.8 to 10

  • Spectroscopic redshifts

  • Extreme (massive) systems

    MB < -26 =>

    Lbol> 1e14 Lo

    MBH > 1e9 Mo

  • Rapidly increasing samples:

    z>4: > 1000 known

    z>5: 80

    z>6: 15

Fan 05


Magorrian, Tremaine, Gebhardt, Merritt… objects in universe from z=0.8 to 10

QSO host galaxies – MBH -- Mbulge relation

  • Most (all?) low z spheroidal galaxies have SMBH: MBH=0.002 Mbulge

  • ‘Causal connection between SMBH and spheroidal galaxy formation’

  • Luminous high z QSOs have massive host galaxies (1e12 Mo)


MAMBO surveys of z>2 QSOs objects in universe from z=0.8 to 10

1e13 Lo

2.4mJy

  • 1/3 of luminous QSOs have S250 > 2 mJy, independent of redshift from z=1.5 to 6.4

  • LFIR =1e13 Lo = 0.1 x Lbol: Dust heating by starburst or AGN?


L objects in universe from z=0.8 to 10FIR vs L’(CO)

z>2

1000Mo/yr

J1148+525

z=6.42

Index=1

1e11 Mo

Index=1.7

  • M(H_2) = X * L’(CO), X=4 (Milkyway), X=0.8 (ULIRGs)

  • Telescope time: t(dust) = 1hr, t(CO) = 10hr


Pushing into reionization: QSO 1148+52 at z=6.4 objects in universe from z=0.8 to 10

  • Highest redshift quasar known (tuniv = 0.87Gyr)

  • Lbol = 1e14 Lo

  • Black hole: ~3 x 109 Mo (Willot etal.)

  • Gunn Peterson trough (Fan etal.)


1148+52 z=6.42: Dust detection objects in universe from z=0.8 to 10

MAMBO 250 GHz

3’

S250 = 5.0 +/- 0.6 mJy

LFIR = 1.2e13 Lo

Mdust =7e8 Mo

Dust formation?

  • AGB Winds ≥ 1.4e9yr

  • tuniv = 0.87e9yr

    => dust formation associated with high mass star formation:Silicate gains (vs. eg. Graphite) formed in core collapse SNe (Maiolino et al 2007)?


1148+52 z=6.42: Gas detection objects in universe from z=0.8 to 10

46.6149 GHz

CO 3-2

Off channels

Rms=60uJy

VLA

IRAM

  • FWHM = 305 km/s

  • z = 6.419 +/- 0.001

  • M(H2) ~ 2e10 Mo

  • Mgas/Mdust ~ 30 (~ starburst galaxies)

  • C, O production (3e7 Mo) => Star formation started early (z > 10)?

VLA


1148+52 objects in universe from z=0.8 to 10

CO Excitation

2

  • Tk ~ 100K

  • nH2 ~ 105 cm-3

    => Typical of starburst galaxy nucleus (eg. NGC 253)


1148+5251 objects in universe from z=0.8 to 10

Radio-IR SED

TD = 50 K

Radio-FIR correlation

  • FIR excess = 50K dust

  • Radio-FIR SED follows star forming galaxy

  • SFR ~ 3000 Mo/yr => form large spheroid in dynamical timescale ~ 1e8 yr


[CII] 158um PDR cooling line detected at z=6.4 objects in universe from z=0.8 to 10

PdBI Walter et al.

30m 256GHz

Maiolino etal

1”

0.3”

  • Size ~ 0.5” (~ 2.5kpc)

  • SFR ~ 6.5e-6 L[CII] ~ 3000 Mo/yr

  • Enriched ISM on kpc scales

  • L[CII] = 4x109 Lo

  • L[CII]/LFIR = 3x10-4 ~ ULIRG


J1148+52: VLA imaging of CO3-2 objects in universe from z=0.8 to 10

0.4”res

rms=50uJy at 47GHz

1”

0.15” res

  • Separation = 0.3” = 1.7 kpc

  • TB = 35K => Typical of starburst nuclei

  • Merging galaxies?

CO extended to NW by 1” (=5.5 kpc) tidal(?) feature


Breakdown M objects in universe from z=0.8 to 10BH - Mbulge relation at high z: SMBH forms first?

CO FWHM + size:

Mdyn ~ 5e10 Mo

(Mgas ~ 2e10 Mo)

Expected

MBH ~ 2e9 Mo

=>Mbulge ~ 1.5e12 Mo

x

1148+5251


J1148 z=6.4: gas, dust, star formation objects in universe from z=0.8 to 10

  • FIR excess ~ 1e13Lo, Md~7e8Mo

  • Giant molecular gas cloud ~ 2e10Mo, size ~ 5.5kpc

  • Star formation rate ~ 3000 Mo/yr

    1. Radio-FIR SED

    2. Gas reservoir + Dust/Gas

    3. CO excitation, TB

    4. [CII]/FIR ~ ULIRG

  • Merging galaxy: Mdyn (r<2.5kpc) ~ 5e10 Mo

  • Early enrichment of heavy elements and dust => star formation started tuniv < 0.5 Gyr

  • Dust formation in massive stars?

  • Break-down of M- at high z?

  • ‘Smoking gun’ for coeval formation of massive galaxy + SMBH within 870 Myr of big bang?

  • Consistent with ‘downsizing’ in massive galaxy and SMBH formation(Heckman etal. 2004; Cowie et al. 1996)


High z submm detected QSOs: Similar to low z IR-selected QSOs = star formation?

Z~6 FIR QSOs

Z~6

Low z IR QSOs: major mergers AGN+starburst?

Low z Optical QSOs: late-type hosts


The ALMA revolution -- observing normal galaxies into cosmic reionization: Panchromatic view of galaxy formation

LFIR = 1e11 Lo

ALMA reveals the cool universe: dust and gas -- the fundamental fuel for star formation

cm: star formation, AGN

(sub)mm dust, molecular gas

Near-IR: stars, ionized gas, AGN


Cosmic Stromgren Sphere reionization: Panchromatic view of galaxy formation

  • Accurate redshiftfrom CO: z=6.419+/0.001

    Ly a, high ioniz Lines: inaccurate redshifts (z > 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

    tqso = 1e5 R^3 f(HI)~ 1e7yrs

    or

    f(HI) ~ 1 (tqso/1e7 yr)


Loeb & Rybicki 2000 reionization: Panchromatic view of galaxy formation


CSS: Constraints on neutral fraction at z~6? reionization: Panchromatic view of galaxy formation

  • 9 z~6 QSOs with CO or MgII redshifts:<R> = 4.4 Mpc (Wyithe et al. 05; Kurk et al. 07)

  • GP => f(HI) > 0.001

  • If f(HI) ~ 0.001, then <tqso> ~ 1e4 yrs – implausibly short given QSO fiducial lifetimes (~1e7 years)?

  • Probability arguments suggest: f(HI) > 0.1

P(>x_HI)

Wyithe et al. 2005

90% probability

x(HI) > curve

=tqso/4e7 yrs


Cosmic ‘phase transition’? reionization: Panchromatic view of galaxy formation

  • CSS (+ Stromgren surfaces) suggest rapid rise in f(HI) around z ~ 6 to 7?

  • But cf. Maselli 07: f(HI)  R^-3


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


Multiple experiments under-way: ‘pathfinders’ ~1e4 m^2 observations (100 – 200 MHz)

LOFAR (NL)

MWA (MIT/CfA/ANU)

SKA 1e6 m^2

21CMA (China)


Signal I: observations (100 – 200 MHz) Global (‘all sky’) reionization signature in low frequency HI spectra

Gnedin & Shaver 03

140MHz

IGM heating: Tspin= TK > TCMB

Ly coupling: Tspin=TK < TCMB

All sky => Single dipole experiment with (very) carefully controlled systematics (signal <1e-4 sky), eg. EDGES (Rogers & Bowman 07)


Signal II: observations (100 – 200 MHz) HI 21cm Tomography of IGM Zaldarriaga + 2003

z=12

9

7.6

  • TB(2’) = 10’s mK

  • SKA rms(100hr) = 4mK

  • LOFAR rms (1000hr) = 80mK


Signal III: observations (100 – 200 MHz) 3D Power spectrum analysis

only

LOFAR

 + f(HI)

SKA

McQuinn + 06


Signal IV: Cosmic Web after reionization observations (100 – 200 MHz)

Ly alpha forest at z=3.6 ( < 10)

Womble 96

N(HI) = 1e13 – 1e15 cm^-2, f(HI/HII) = 1e-5 -- 1e-6

=> Before reionization N(HI) =1e18 – 1e21 cm^-2


Signal IV: observations (100 – 200 MHz) Cosmic web before reionization: HI 21Forest

19mJy

z=12

z=8

130MHz

159MHz

  • Perhaps easiest to detect (use long baselines)

  • Requires radio sources: expect 0.05 to 0.5 deg^-2 at z> 6 with S151 > 6 mJy?

  • radio G-P (=1%)

  • 21 Forest (10%)

  • mini-halos (10%)

  • primordial disks (100%)


Signal V: observations (100 – 200 MHz) Cosmic Stromgren spheres around z > 6 QSOs

  • LOFAR ‘observation’:

  • 20xf(HI)mK, 15’,1000km/s

  • => 0.5 x f(HI) mJy

  • Pathfinders: Set first hard limits on f(HI) at end of cosmic reionization

  • Easily rule-out cold IGM (T_s < T_cmb): signal = 360 mK

5Mpc

0.5 mJy

Wyithe et al. 2006


Challenge I: observations (100 – 200 MHz) 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/deg^2 with S140 > 1 Jy


Solution: spectral decomposition observations (100 – 200 MHz)(eg. Morales, Gnedin…)

Freq

Signal/Sky ~ 2e-5

Signal

10’ FoV; SKA 1000hrs

Foreground

Xcorrelation/Power spectral analysis in 3D – different symmetries in freq space


Challenge II: observations (100 – 200 MHz) Ionospheric phase errors – varying e- content

  • TIDs – ‘fuzz-out’ sources

  • ‘Isoplanatic patch’ = few deg = few km

  • Phase variation proportional to ^2

  • Solution:

  • Wide field ‘rubber screen’ phase self-calibration

15’

Virgo A VLA 74 MHz Lane + 02


Challenge III: observations (100 – 200 MHz) Interference

100 MHz z=13

200 MHz z=6

  • Solutions -- RFI Mitigation (Ellingson06)

  • Digital filtering

  • Beam nulling

  • Real-time ‘reference beam’

  • LOCATION!


VLA-VHF: 180 – 200 MHz Prime focus X-dipole observations (100 – 200 MHz)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: Winter 06/07


Project abandoned: Digital TV observations (100 – 200 MHz)

KNMD Ch 9

150W at 100km


RFI mitigation: location, location location… observations (100 – 200 MHz)

100 people km^-2

1 km^-2

0.01 km^-2

(Briggs 2005)


Destination: Moon! observations (100 – 200 MHz)

RAE2 1973


  • Focus: Reionization (power spec,CSS,abs) observations (100 – 200 MHz)

  • Very wide field: 2x2 tile(?)

  • Correlator: FPGA-based from Berkeley wireless lab

  • Staged engineering approach: GB05 8 stations  Boolardy07 16 stations


PAPER: First images/spectra observations (100 – 200 MHz)

Cas A 1e4Jy

180MHz

140MHz

Cygnus A

1e4Jy

CygA 1e4Jy

3C348 400Jy

3C392

200Jy


GMRT 230 MHz – HI 21cm abs toward highest z radio galaxy and QSO (z~5.2)

RFI = 20 kiloJy !

232MHz 30mJy

229Mhz0.5 Jy

rms(40km/s) = 3mJy

rms(20km/s) = 5 mJy

N(HI) ~ 2e20TS cm^-2 ?


Radio astronomy probing cosmic reionization and QSO (z~5.2)

  • ‘Twilight zone’: obs 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


END and QSO (z~5.2)


ALMA first fringes (Emerson +) and QSO (z~5.2)

ATF, Socorro NM

Saturn 90 GHz March 2, 2007

Using all ALMA electronics


ALMA Status and QSO (z~5.2)

  • Antennas, receivers, correlator all fully prototyped and evaluated: best mm receivers and antennas ever!

  • Site construction well under way: Observation Support Facility and Array Operations Site

  • North American ALMA Science Center (C’Ville): gearing up for science commissioning and operations (successful international operations review Feb 2007)

  • Timeline:

    Q1 2007: First fringes at ATF (Socorro)

    Q1 2009: Three antenna array at AOS

    Q3 2010: Start early science (16 antennas)

    Q4 2012: Full operations


Signal VI: and QSO (z~5.2) pre-reionization HI signal

eg. Baryon Oscillations (Barkana & Loeb)

  • Very difficult to detect !

  • z=50 => n = 30 MHz

  • Signal: 30 arcmin, 50 mk =>S_30MHz= 0.1 mJy

  • SKA sens in 1000hrs:

  • T_fg = 20000K =>

  • rms = 0.2 mJy

z=50

z=150


HCN emission: Dense gas directly associated with star formation

n(H2) > 1e5 cm^-3 (vs. CO: n(H2) > 1e3 cm^-3)

z>2

J1148+52

Solomon et al

z=2.58

70 uJy

index=1


Line sensitivity formation

High order, fine structure lines

Low order


The ALMA revolution formation

  • Spectral simulation of J1148+5251

  • Detect dust emission in 1sec at 250GHz

  • Detect multiple lines, molecules per band => detailed astrochemistry

  • Image dust and gas at sub-kpc resolution – gas dynamics++

CO

HCO+

HCN

CCH

  • Studying 1st galaxies

  • Detect ‘normal’ (eg. Ly), star forming galaxies at z>6 in few hours

  • Determine redshifts directly from mm spectroscopy for dusty systems

z=6.55

SFR~10Mo/yr


Stratta, Maiolino et al. 2006: extinction toward z=6.2 QSO and 6.3 GRB =>

Silicate + amorphous Carbon dust grains (vs. eg. Graphite) formed in core collapse SNe?


Sources responsible for reionization and 6.3 GRB =>

  • 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 z>10? midIR BG (Kashlinsky05), but trecomb < tuniv at z~10

  • GP => Reionization occurs in ‘twilight zone’, opaque for obs <0.9 m

Needed for reion.


[CII] -- the good and the bad and 6.3 GRB =>

  • [CII]/FIR decreases rapidly with LFIR (lower heating efficiency due to charged dust grains?) => luminous starbursts are still difficult to detect in C+

  • Normal star forming galaxies (eg. LAEs) are not much harder to detect!


z>6 QSOs with CO and/or MgII redshifts and 6.3 GRB => (Wyithe et al. 05)

<z> ~ 0.08 => <R> = 4.4 Mpc


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