JWST/NIRSpec spectrum, NIRCam, and pseudo-NIRCam images (NIRSpec-IFU based) of the Cosmic Gems arc. Top: 1D NIRSpec prism spectrum (from the PSF-matched cube) extracted from the full arc (with its aperture mask shown in the bottom-central panel), showing the large Lyα-break and damping at ≃1.3 μm, along with two weak emission lines, Hβ and [O III] λ4959, on the rightmost side of the spectral range. A weak Balmer break is also detected (Section 4). The 1σ uncertainty spectrum is shown in red. The wavelengths corresponding to the main undetected UV and optical lines are shown with dashed lines. The throughputs of the NIRCam filters covering the field are shown in green, for reference. Bottom: From left to right, JWST/NIRCam stacked F150W + F200W image with the NIRSpec-IFU field of view outlined; collapsed NIRSpec IFU data cube in the rest-UV (covering the observed wavelength range of F150W and F200W), before (middle) and after (right) PSF-matching. The last panel also includes the outlines of the masks used to extract the 1D spectra for the regions discussed in the main text.