CFHT UM2025 - Presentation Details
Abstract Details
Title: Medium-band imaging for future astronomy and cosmology
Presenter: Dustin Lang
Abstract:
Large-scale imaging surveys have, to date, largely used broad-band photometric filters. However, using medium-band filters with 5x better spectral resolution unlocks a range of science cases of broad interest, from Galactic structure to galaxy evolution to cosmology. For example, such imaging can be used as powerful metallicity and log(g) indicators for stars; provides greatly improved photometric redshifts; and allows very clean selection of high-redshift galaxies (2 < z < 3.5) based on Lyman-alpha emission. We have begun a 90-night pathfinder survey on DECam, IBIS (the Intermediate-Band Imaging Survey), using a new custom-built set of 5 filters that evenly divide the g band into ~260-Angstrom-wide bands. A complementary survey is being proposed using Hyper-SuprimeCam on Subaru, and we propose including medium-band imaging as part of the upcoming CFHT Community Survey, which would strengthen and extend the UNIONS science cases, while providing data complementary to LSST's broad-band imaging and taking advantage of MegaCam's excellent performance in the blue.