A successor to the prolific CHIME Canadian telescope array is under construction – and the first big test is coming up soon.
Consortium members expect to do the first test run this fall on dishes of CHORD, a set of radio telescopes also known as the Canadian Hydrogen Observatory and Radio-transient Detector. The campaign will include hardware, software and science testing.
Construction on CHORD began in January, and roughly 50 of the dishes should be completed by the end of 2025, according to a recent consortium statement. CHORD will be a large project indeed: 640 antennas, each with a six-metre dish, will be deployed by the end of 2027.
The bulk of the array – 512 antennas – will be hosted at the National Research Council’s Dominion Radio Astrophysical Observatory, near Penticton, British Columbia, which is the main location for CHIME. Two outrigger stations will also be constructed, with 64 antennas each, in northern California and central West Virginia.
All of this hardware is devoted to big astronomical questions including the search for fast radio bursts (FRBs), which are brief and powerful radio signals lasting less than a second. CHIME – the Canadian Hydrogen Intensity Mapping Experiment – has detected thousands of FRBs since it was first deployed in 2017, as the telescope array is optimized to look at the entire sky.
“The CHORD outrigger stations will dramatically enhance the scientific return of the project by enabling precise localizations for the FRBs detected by the core array,” Juan Mena-Parra, a senior science group member for the instrument from the Dunlap Institute for Astronomy and Astrophysics at the University of Toronto, said in the same statement.
“This level of accuracy allows us to confidently identify the host galaxies and source environments of FRBs, key steps toward understanding their origins and unlocking their power as probes of the large-scale structure of the universe,” Mena-Perra added.
Concerning FRBs, CHORD is optimized to examine fainter signals and more frequencies than CHIME itself. The expectation is these capabilities will allow researchers to statistically map these bursts, as well as electrons, in the universe at large – allowing researchers to “find more FRBs and understand them in greater detail,” stated Kendrick Smith, who leads CHORD’s software design at the Perimeter Institute for Theoretical Physics.
CHORD will also examine dark energy – thought to drive the expansion of the universe, but poorly understood – as well as fundamental particles, among other investigations, according to a consortium statement. The science page of CHORD lists many investigations it will be expected to perform:
– 21-cm intensity mapping “will map the large-scale structure of the universe”, as well as the evolution of dark energy.
– 21-cm galaxy surveys would allow for detecting low-redshift galaxies.
– More pulsars will be mapped, with investigators expecting to grow numbers from 2,800 today to more than 10,000.
– Investigations are also ongoing into how magnetic fields were formed and evolved, as well as following up on gravitational wave events, among other science work.
McGill University Physics Professor Matt Dobbs, one of the project leads, framed CHORD as “an order of magnitude more powerful than its predecessor, the CHIME telescope” for the benefit of these various investigations.
Much of the key tech in the array is Canadian, Dobbs pointed out: the NRC’s Herzberg Astronomy and Astrophysics Research Centre created pioneering single-piece reflectors, for example, and the software and analytic tools were also made in Canada.
Funding comes courtesy of the Canada Foundation for Innovation. Key institutions building the telescope are McGill University, the University of Toronto, the National Research Council, the Perimeter Institute and the University of Calgary.
Other Canadian partners include Queen’s University, the University of British Columbia and York University, while international partners include Arizona State University, Italy’s Instituto Nazionale di Astrofisica, the Massachusetts Institute of Technology and West Virginia University.