Colloq Abstract - Vanderlinde

September 9, 2016

11am Mountain

Keith Vanderlinde

U Toronto

 

The Canadian Hydrogen Intensity Mapping Experiment (CHIME)

Abstract

Hydrogen Intensity (HI) mapping uses redshifted 21cm emission from neutral hydrogen as a 3D tracer of Large Scale Structure (LSS) in the Universe. Imprinted in the LSS is a remnant of the acoustic waves which propagated through the primordial plasma. This feature, the Baryon Acoustic Oscillation (BAO), has a physical size of ~150 co-moving Mpc which appears in the spatial correlation of LSS. By charting the evolution of this scale over cosmic time, we trace the expansion history of the Universe, constraining  the Dark Energy equation of state as it begins to dominate the expansion of the Universe, particularly at redshifts poorly probed by current BAO surveys.

In this talk I will introduce CHIME, an ambitious new radio telescope in British Columbia, Canada. CHIME is a transit interferometer designed to measure the BAO via 21cm line emission, covering a bandwidth of 400-800MHz, corresponding to a redshift range of 0.8 < z < 2.5. It is composed of four 20m x 100m parabolic reflectors which focus radiation in one direction (east-west) while interferometry is used to resolve beams in the other (north-south). Earth rotation sweeps these beams across the sky, resulting in complete daily coverage of the northern celestial hemisphere.

In this talk, I will discuss the motivation, design, and status of both the full CHIME instrument and the reduced-scale CHIME Pathfinder which has been in operation since.

 

 

 

 

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