CRA Seminar (Dr. Keith Vanderlinde, University of Toronto)

Title: CHIME – the Canadian Hydrogen Intensity Mapping Experiment

Keith Vanderlinde (University of Toronto)

URL: http://dunlap.utoronto.ca/~vanderlinde/

ABSTRACT:

Among the great surprises of modern cosmology was the discovery of
Dark Energy, which dominates the energy budget of the Universe and
is driving the acceleration of its expansion rate. Decyphering its
properties and nature will require novel measurements spanning vast
swaths of the observable Universe. In this talk, I will introduce
the Canadian Hydrogen Intensity Mapping Experiment (CHIME), an
ambitious project to study Dark Energy by tracing out 4 billion years
of cosmic history, using a purpose-built radio telescope at the
Dominion Radio Astrophysical Observatory (DRAO) in B.C.’s Okanagan
Valley.

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 acoustic waves which
propagated through the primordial plasma of the nascent cosmos. This
“Baryon Acoustic Oscillation” (BAO) feature, which appears as a
spatial correlation of LSS, can be used as a standard ruler to trace
the expansion history of the Universe, thereby allowing us to constrain
the Dark Energy equation of state.

CHIME is a transit interferometer with no moving parts, which uses a
massive computing backend to image the radio sky from 400-800MHz,
corresponding to 21cm radiation emanating from a redshift range of
0.8 < z < 2.5. Earth rotation sweeps its field of view across the sky,
resulting in complete daily coverage of the northern celestial
hemisphere
and an unprecedented survey sensitivity. I will discuss the motivation,
construction, and status of CHIME, as well as a pair of extensions which
probe the high-cadence time-domain radio sky, monitoring radio pulsars
and
exploring a more recent mystery in radio astronomy, Fast Radio Bursts.