Fast Radio Bursts
Fast Radio Bursts (FRBs) are mysterious, millisecond bursts of radio light of unknown origin coming from far outside our Milky Way galaxy. Localizing FRBs to a host galaxy and local environment is key to understanding their nature, and for harnessing their potential as cosmic probes. CHORD will localize thousands of FRBs in real time with unparalleled precision.
21 cm Intensity Mapping
CHORD will map the large-scale structure of the Universe through intensity mapping of the 21 cm emission line. CHORD will particularly shine in its measurement of the evolution of dark energy over the redshift range z=0-3.7. CHORD is forecast to significantly improve upon existing constraints on the dark energy equation of state, and be competitive with future experiments costing significantly more.
21 cm Galaxy Survey
At low redshift, CHORD will be able to detect individual galaxies via the 21 cm emission line. Owing to its high sensitivity and large field of view, CHORD is forecast to detect between 106-107 low-redshift galaxies. This would provide a factor of 30-300 improvement over ALFALFA, the largest 21 cm galaxy survey to date.
Pulsars
CHORD will have the potential to dramatically increase the number of known Galactic pulsars, from ~2,800 today to beyond 10,000. Finding large numbers of pulsars raises the likelihood of discovering exotic systems, which are excellent laboratories for testing theories of relativistic gravity. Precision timing of newly-discovered millisecond pulsars can also aid in detecting the gravity waves from mergers of supermassive black holes.
Cosmic Magnetism
The origin and evolution of magnetic fields in the Universe remains an unsolved cosmological problem, with implications for the growth of structure, galaxy evolution, and star formation. CHORD’s ultra-wide bandwidth will make it a powerful tool for mapping the magneto-ionic environment of the Interstellar and Circumgalactic Medium via Faraday tomography.
Multi-Wavelength/ Messenger Science
CHORD's wide sky coverage and bandwidth will have significant overlap with current and future surveys of other cosmological tracers, enabling cross-correlation studies. These same qualities will also lend CHORD to multi-wavelength followup of transient phenomena such as gravitational waves.