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Spin, T S. CMB. Kinetic. Ionized fraction x i = 1 - x HI. Mean brightness temperature. Pritchard & Loeb 2008. 3 observational techniques: 21 cm forest Power spectrum/tomography Global spectrum. 1. 21 cm forest. But not until 2020+. Carilli et al. (2004). 2. Power spectrum. (3D)

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## Kinetic

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**Spin, TS**CMB Kinetic Ionized fraction xi = 1 - xHI Mean brightness temperature Pritchard & Loeb 2008**3 observational techniques:**• 21 cm forest • Power spectrum/tomography • Global spectrum**1. 21 cm forest**But not until 2020+ Carilli et al. (2004)**2. Power spectrum**(3D) z~100 (2D) 21 cm CMB Kleban et al. 2007 Loeb & 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**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) Code from J. Pritchard**3. Global spectrum**Primordial BH evaporation Mack & Wesley (2008)**Murchison Widefield Array (MWA)**Science: 21 cm cosmology, heliosphere, transients, and Galactic physics**MWA: Antenna Tile**1 2 3**MWA**32 tiles 150 m**MWA first image with correlator**Parkes reference image 32 MHz multi-frequency synthesis with 32 tiles [13 Jan 2010] – 5 minute snapshot C. Williams (MIT)**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. 2009 MWA uncertainty from Bowman et al. 2006**Experiment to Detect the**Global Epoch of Reionization Signature (EDGES)**EDGES**Bowman & Rogers 2010**EDGES block diagram**ou t of band noise injection AEER**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**Internally-switched calibration**Noise source (p1) Internal load (p0) Antenna (p2) p1– p0 “Calibrated” sky spectrum w/ RFI filtering and integration “Calibrated” sky spectrum T_A ~ (p2 – p0) / (p1 – p0) p2 – p0**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**Parameter estimation**#1: 21 cm reionization model #2: Foreground model 2 science parameters: z and zr 4-19 nuisance parameters: an Pritchard & Loeb (2010, submitted)**Lower limit on duration**zr > 0.06 for 6 < zr < 13 (95% confidence) Bowman & Rogers, Nature, 468, 7325, pp. 796-798 (2010)**EDGES reionization forecast**Pritchard & Loeb (2010)**21 cm array site selection**Sydney Narrabri MRO 100 MHz 1 GHz Annotated by F. Briggs**US TV and FM radio “pollution”**West Forks, Maine D1 Array – Haystack Obs.**Catlow Valley, Oregon, US**EDGES Memo#052, AEER, JDB, 2009 60 dB 80 MHz 200 10 dB

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