UNIONS - the Ultraviolet Near Infrared Optical Northern Survey

The Hawaíi UNIONS Survey is a legacy program that will help address some of the most fundamental issues in astronomy, including the properties of dark matter and dark energy, the growth of structure in the Universe from Galactic to cluster scales, and the assembly of the Milky Way. These ambitious goals are achievable only with homogeneous, multi-wavelength data covering large, contiguous areas of the sky. Such a survey is essential to the primary science goals of the ESA Euclid Mission, a Stage-IV dark-energy experiment that will also enable the tomography of dark matter in the universe with ground-based photometric redshifts and Euclid weak-lensing measurements. The Ultraviolet Near-Infrared Optical Northern Sky (UNIONS) Survey is a collaboration of four different independent surveys: (i) the ongoing ongoing Pan-STARRS Wide Area Survey for NEOs with both PS1 and PS2 in i and z band, (ii) the Canada France Imaging Survey (CFIS) in u and r band, (iii) the Waterloo Hawaii Institute for Astronomy G-band Survey (WHIGS) in g band, and (iv) the Wide Imaging with Subaru HSC of the Euclid Sky (WISHES) in z band. UNIONS is thus a five band ugriz survey of the 5000 square degrees bounded by declination dec > 30, Galactic latitude |b| > 25, and ecliptic latitude |β| > 15. The Pan-STARRS data includes the net archival observations in i and z band. CFIS exploits the unparalleled u band sensitivity and excellent r band and image quality of CFHT/Megacam. The WISHES and WHIGS surveys both take advantage of the excellent image quality and performance of the Hyper Suprime Camera on the Subaru Telescope in Hawaii. The combination of these surveys is the Hawaíi UNIONS Survey and it will be the dominant ground-based multi-band ugriz wide-field survey for the extragalactic sky in the northern hemisphere for the foreseeable future. The status, progress, and expected Data Releases will be presented.