Program Overview


CANUCS will use all three of JWST's near-infrared instruments. The NIRISS low-resolution grisms will provide spectra of thousands of galaxies per field. NIRCam imaging will sample the galaxies structures and SEDs from 0.8 to 5 microns. NIRSpec follow-up low resolution spectroscopy will target galaxies discovered by NIRCam and NIRISS as well as those for which NIRISS does not provide a redshift.

High-z Low Mass Galaxies

With the power of gravitational lensing we will find and study low-mass galaxies across all epochs. We will search for the earliest galaxies, in rest-frame UV continuum and Lyman alpha line emission.

Resolved Emission Line Maps

With low-resolution grism spectroscopy we can isolate nebular line emission and make emission line ratio maps, in order to understand physical properties like SFR, dust, metallicity and ionization.

Quenching in cluster environments

We will study how galaxies are transformed as they fall into dense galaxy clusters.


The CAnadian NIRISS Unbiased Cluster Survey (CANUCS) is a component of the NIRISS Guaranteed Time Observations survey that will devote 200 hours to study galaxies lensed by five massive foreground galaxy clusters. More information to come; targets and observation strategy available at JWST-GTO 1208.

Target Redshift RA Dec
Abell 370 0.375 02:39:54.1 -01:34:34
MACS 0416 0.395 04:16:09.4 -24:04:20
MACS 0417 0.443 04:17:35.1 -11:54:38
MACS 1149 0.543 11:49:36.7 +22:23:53
MACS 1423 0.545 14:23:47.8 +24:04:40