Using state-of-the-art reduction methods, we analyze the new JWST data acquired by the NIRISS wide-field slitless spectroscopy (WFSS) and NIRSpec multi-object spectroscopy (MOS). The cross calibration of these two complementary modes opens up key window on unbiased investigation of star formation, feedback, and ISM properties in and beyond the cosmic noon epoch. We bring forth the first spatially resolved analysis of high-redshift galaxies with JWST WFSS and measure the first gas-phase metallicity radial gradient with sub-kpc resolution at z≥3. Using the NIRSpec MOS in high-resolution gratings, we compile a large sample of 35 galaxies at z~1-9 whose [O II]λλ3726,3729 and [S II] λλ6718,6732 line doublets are well resolved to shed light upon their ISM electron density and ionization properties. The exquisite sensitivity and wavelength coverage of the NIRSpec MOS in prism mode gives us an excellent chance to identify unique spectral features in galaxies in the epoch of reionization. We discover one of the highest redshift galaxies, spectroscopically confirmed at z=8.16, with PopIII-like stellar populations. This galaxy candidate hosting the first generation stars opens up new key frontiers on galaxy evolution and stellar physics in the early Universe.
