2022B - 2024A CFHT Large Programs

These Large Programs will be executed from the 2022B to the 2024A semesters.

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Ultraviolet Near Infrared Optical Northern Survey (UNIONS)

PI: Dr. Jean-Charles Cuillandre

Instrument: MegaCam, 69.72 nights allocated.

Abstract -- The Ultraviolet Near Infrared Optical Northern Survey (UNIONS) is positioned to become the major multi-band (ugriz) ground-based wide-field survey in the northern hemisphere in the imminent era of Euclid, Rubin and multi-messenger astrophysics. UNIONS brings together 202 astronomers from the international community and is a close collaboration of three major Hawaii-based facilities - Subaru, Pan-STARRS, and CFHT. This proposal seeks to leverage key niches of MegaCam on CFHT - blue sensitivity, image quality and low surface brightness imaging - to complete the necessary coverage for the u and r bands. UNIONS is a strategic platform for wide field astronomy and is already providing a new view of the outer stellar halo of the Milky Way and is a key dataset for weak-lensing measurements that are probing the distribution of dark matter in galaxy groups and clusters. Critically, UNIONS provides the key northern ground-based photometry for the Euclid space mission which requires complete and contiguous ugriz photometry over 4,861 square degrees of the northernmost sky. Without the u and r data provided by UNIONS, Euclid will not have the necessary information to make its primary Stage IV dark energy measurements.

Website: Canada-France Imaging Survey (CFIS UNIONS)


SPICE: Consolidating & Enhancing the SPIRou Legacy Survey

PI: Dr. Jean-Fran├žois Donati

Instrument: SPIRou, 174.28 nights allocated.

Abstract -- Aimed at detecting and characterizing Earth-like exoplanets around nearby M dwarfs, and at studying the impact of magnetic fields in the early life of low-mass stars and their planets, the SPIRou Legacy Survey (SLS) was allocated 300 CFHT nights from 2019A to 2022A. With a final semester still ongoing, the SLS has already achieved numerous key results on both scientific fronts. We propose a new LP with SPIRou, called SPICE, to consolidate & enhance the SLS results by concentrating on a sample of late-M dwarfs, TESS candidates and pre-main-sequence (PMS) stars that were not monitored within the SLS. The goal is to achieve the best possible characterization of nearby exoplanets to optimize future studies of these targets with JWST, ARIEL and the ELTs; for PMS stars, we need to push further the SLS exploration by extending the parameter space and concentrating now on very-low-mass and strongly-accreting objects. Altogether, SPICE requires 224 nights to reach its new science goals, for which an LP is mandatory to achieve the requested monitoring; besides, SPICE data will be used to further boost the performance of the SPIRou reduction pipeline, thereby pursuing the work initiated with the SLS.

Website: The SPIRou Legacy Survey (SLS)


The Classical and Large-a Distant Solar SYstem (CLASSY) Survey: Measuring TNO Sizes and Orbits to Test Planet Formation History

PI: Dr. Wes Fraser

Instrument: MegaCam, 56 nights allocated.

Abstract -- Here we propose CLASSY: the Classical and Large-A Solar SYstem survey. This survey has two primary goals: to provide observational tests of the cutting-edge planet formation models; and to test cosmogonic models of orbital emplacement. Using shift'n'stack techniques, we will discover and track trans-Neptunian objects (TNOs) at fainter limits (m_r=26.5) and across a wider range of the sky than has ever been accomplished at these depths, and fill in a critical range of sizes between contemporary ground-based surveys, and narrow area space-based surveys that go fainter still. We will carefully measure the size-frequency distribution of classical TNOs in a range that is critical for determining properties of the streaming instability and cloud collapse mechanisms that formed TNOs. We will also discover distant TNOs which will test emplacement models and planet migration history. CLASSY will be significantly more sensitive to these ultra-distant bodies which are at the edge of detectability of past surveys. CLASSY is the first survey designed from the ground up to avoid longitudinal discovery biases, which may be the root cause of the apparent extreme TNO clustering, the primary evidence for the existence of Planet 9.