Abstract

In this talk I will present the statistics of z~6-9 galaxy outflows indicated by spatially-extended gas emission and broad lines in the JWST NIRCam imaging and NIRSpec spectroscopy respectively. With a total of 61 spectroscopically confirmed galaxies at z~6-9 in the JWST CEERS, GLASS, and ERO data, we find five galaxies with [Oiii]+Hb ionized gas emission significantly extended beyond the kpc-scale stellar components based on the emission line images constructed by the subtraction of NIRCam broadband (line on/off-band) images. The number fraction of galaxies with the spatially extended gas, 5/32, at z~6-9 is an order of magnitude higher than those at z~0-1, which can be explained by events triggered by frequent major mergers at high redshift. We also investigate medium- and high-resolution NIRSpec spectra of 30 galaxies at z~6-9, and identify five galaxies with broad (140-800 km/s) lines in the [Oiii] forbidden line emission, suggestive of ongoing galaxy outflows. All of the galaxies with broad lines have outflow velocities smaller than the escape velocities of their dark matter halos, indicating that outflows in these galaxies cannot eject hot ionized gas into IGM. The existence of galaxies with/without spatially-extended gas emission or broad lines may suggest that these are galaxies in the early, late, post phases of galaxy outflows at high redshift, where the relatively large fractions of such galaxies indicate the longer-duration and/or more-frequent outflows at the early cosmic epoch.