CHIME

CHIME is a novel radio telescope: four 20m × 100m cylindrical reflectors that focus the sky into long north-south primary beams, then interferometrically processed in a powerful digital correlator to yield a fan of formed beams. Earth's rotation sweeps that fan across the sky, and CHIME surveys the entire northern celestial hemisphere every sidereal day — with no moving parts.

CHIME was originally designed to map the cosmologically redshifted 21cm emission of neutral hydrogen, using HI as a tracer of large-scale structure to detect the Baryon Acoustic Oscillation (BAO) feature and reconstruct the expansion history of the Universe. That program is now bearing fruit, with the first detection of cosmological 21cm emission with CHIME in cross-correlation with eBOSS, and a follow-up detection of 21cm emission in CHIME autocorrelation.

The CHIME ecosystem

CHIME's compute backend has been repeatedly extended, and the telescope now hosts a family of commensal experiments, including:

• CHIME/FRB — by far the largest detector of Fast Radio Bursts in the world. The first CHIME/FRB catalogue contains 535 bursts; the second catalogue is several times larger.
• CHIME/FRB Outriggers — a continent-wide VLBI network that localizes FRBs to their host galaxies on the fly. I spearheaded the early design and pathfinding work; others have since taken up the lead. Design Overview (2025).
• CHIME/Pulsar — daily-cadence timing of hundreds of pulsars across the northern sky.

My role

I've been part of CHIME since its pathfinder days. My group has built and operated GPU spatial-processing systems for the array (Denman et al. 2015, 2020), pioneered the initial design of the VLBI Outrigger system, and is actively involved in 21cm cosmology and FRB science across the project.

CHIME is a collaboration of UBC, McGill, U of T (Dunlap and DADDAA), DRAO/NRC, Yale, Perimeter, MIT, West Virginia, and others. Built at DRAO with support from CFI, NSERC, the Dunlap Institute, the Trottier family, and additional partners.