KineticCMB

Ionized fraction xi = 1 - xHI

Mean brightness temperature

Spin, TS

Pritchard & Loeb 2008

3 observational techniques:

1. 21 cm forest2. Power spectrum/tomography3. Global spectrum

1. 21 cm forest

Carilli et al. (2004)

But not until 2020+

2. Power spectrum

CMB

21 cm(3D)z~100(2D)

Kleban et al. 2007Loeb & Zaldarriaga 2004

2. Power spectrum

“Science with the MWA”Greenhill, Bowman, et al. (2010, in prep)

Figure by Matt McQuinn

2. Power spectrum

[21cmFast simulation]

3. Global spectrum

J. Pritchard

3. Global spectrum

Code from J. Pritchard

N_ion

f_esc

f_star

f_lya

f_xray

- Number of ionizing photons per baryon in star formation

- Escape fraction of ionizing photons from galaxies(probably between 0.02 and 0.2)

- Star forming efficiency by mass(uncertain to order of magnitude)

- Number of Ly- photons per baryon in stars (popII)(uncertain to a factor of few)

- X-ray luminosity relative to value extrapolated from Glover and Brand (uncertain to more than order of magnitude)

3. Global spectrum

Mack & Wesley (2008)

Primordial BH evaporation

Murchison Widefield Array(MWA)

Murchison Widefield Array (MWA)

Science: 21 cm cosmology, heliosphere, transients,and Galactic physics

MWA: Antenna Tile

12

1

2

3

MWA

150 m

32 tiles32 tiles

MWA first image with correlator

C. Williams (MIT)

32 MHz multi-frequency synthesis with 32 tiles[13 Jan 2010] – 5 minute snapshot

Parkes reference image

Radio sources w/ MWA

MWA full array rendering

1.5 km

MWA 1-year power spectrum sensitivity

4 redshift bands, 300 hours each

21 cm from Lidz et al. 2009MWA uncertainty from Bowman et al. 2006

Experiment to Detect the Global Epoch of Reionization Signature

(EDGES)

EDGES

EDGES

Bowman & Rogers 2010

AEER

EDGES block diagram

ou t of band noise injection

Internally-switched calibration• 3-position switch to measure (cycle every 10s):

• Solve for antenna temperature:

(Tcal > TL 300 K, TA 250 K, TR 20 K)

• Results: >105 dynamic range achieved with EDGES

• Limitations: – Total power differences between TL and TA can leave systematic errors

– Temporal variations: comparing measurements at different times

Antenna (p2)Internal load (p0)

Noise source (p1)

p1– p0

p2 – p0“Calibrated” sky spectrum

T_A ~ (p2 – p0) / (p1 – p0)

“Calibrated” sky spectrumw/ RFI filtering and integration

Internally-switched calibration

Measured spectrum

Murchison Radio-astronomy Observatory (MRO)

Aug 20 – Oct 20, 2009

1440 wall-clock hours on sky

500 hours after RFI cuts

50 hours eff. integration

+15 dB

Orbcomm LEO satellite constellation

Parameter estimation

#1: 21 cm reionization model

#2: Foreground model

m

n

nnF zaT

0

)1(

Pritchard & Loeb (2010, submitted)2 science parameters: z and zr 4-19 nuisance parameters: an

Lower limit on duration

Bowman & Rogers, Nature, 468, 7325, pp. 796-798 (2010)

zr > 0.06 for 6 < zr < 13 (95% confidence)

EDGES reionization forecast

Pritchard & Loeb (2010)

Why don’t we observe in the U.S.?

21 cm array site selection

Annotated by F. Briggs1 GHz100 MHz

MRO

Narrabri

Sydney

US TV and FM radio “pollution”

D1 Array – Haystack Obs.D1 Array – Haystack Obs.

West Forks, Maine

Catlow Valley, Oregon, US60 dB

10 dB 80 MHz 200

EDGES Memo#052, AEER, JDB, 2009

Thanks! Questions?