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Arxiv: Medium Bands, Mega Science: a JWST/NIRCam Medium-Band Imaging Survey of Abell 2744 Published: 4/19/2024 9:40:00 PM Updated: 4/19/2024 9:40:00 PM

Paper abstract: In this paper, we describe the "Medium Bands, Mega Science" JWST Cycle 2survey (JWST-GO-4111) and demonstrate the power of these data to reveal boththe spatially-integrated and spatially-resolved properties of galaxies from thelocal universe to the era of cosmic dawn. Executed in November 2023,MegaScience obtained ~30 arcmin^2 of deep multiband NIRCam imaging centered onthe z~0.3 Abell 2744 cluster, including eleven medium-band filters and the twoshortest-wavelength broad-band filters, F070W and F090W. Together, MegaScienceand the UNCOVER Cycle 1 treasury program provide a complete set of deep (~28-30mag) images in all NIRCam medium- and broad-band filters. This unique datasetallows us to precisely constrain photometric redshifts, map stellar populationsand dust attenuation for large samples of distant galaxies, and examine theconnection between galaxy structures and formation histories. MegaScience alsoincludes ~17 arcmin^2 of NIRISS parallel imaging in two broad-band and fourmedium-band filters from 0.9-4.8um, expanding the footprint where robustspectral energy distribution (SED) fitting is possible. We provide example SEDsand multi-band cutouts at a variety of redshifts, and use a catalog of JWSTspectroscopic redshifts to show that MegaScience improves both the scatter andcatastrophic outlier rate of photometric redshifts by factors of 2-3.Additionally, we demonstrate the spatially-resolved science enabled byMegaScience by presenting maps of the [OIII] line emission and continuumemission in three spectroscopically-confirmed z>6 galaxies. We show that lineemission in reionization-era galaxies can be clumpy, extended, and spatiallyoffset from continuum emission, implying that galaxy assembly histories arecomplex even at these early epochs. We publicly release fully reduced mosaicsand photometric catalogs for both the NIRCam primary and NIRISS parallelfields.