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Harvard ADS: Dynamics of GN-z11 Explored by JWST Integral Field Spectroscopy: Gaseous Rotating Disk at z=10.60 Suggestive of Weak Feedback?

Paper abstract: We investigate the dynamics of GN-z11, a luminous galaxy at z=10.60, carefully analyzing the public deep integral field spectroscopy (IFS) data taken with JWST NIRSpec IFU. While the observations of the IFS data originally targeted a He II clump near GN-z11, we find that C III]\lambda\lambda1907,1909 emission from ionized gas at GN-z11 is bright and spatially extended significantly beyond the point-spread function (PSF) in contrast with the GN-z11's compact UV-continuum morphology. The spatially extended C III] emission of GN-z11 shows a velocity gradient, red- and blue-shifted components in the NE and SW directions, respectively, which cannot be explained by the variation of [C III]\lambda1907/C III]\lambda1909 line ratios. We perform forward modeling with GalPak^\mathrm{3D}, including the effects of PSF smearing and line blending, and find that the best-fit model is a nearly edge-on disk with a rotation velocity of v_\mathrm{rot}=376_{-151}^{+110} km s^{-1}, a velocity dispersion of \sigma_v=113_{-48}^{+24} km s^{-1}, and a ratio of v_\mathrm{rot}/\sigma_v=3.3_{-1.5}^{+1.7}, indicative of a rotation-dominated disk at z=10.6. Interestingly, the disk rotation velocity is faster than the circular velocity at the virial radius, v_\mathrm{c}(r_{200})=205_{-34}^{+28} km s^{-1}, estimated from the stellar mass, suggesting a compact disk produced under weak feedback such predicted in numerical simulations. In fact, the half-light radius of the C III] emitting gas disk is only 294\pm45 pc, while the one of the stellar UV component is even smaller, 196\pm12 pc. While higher S/N data are necessary for a conclusion, these observational results would suggest that GN-z11 has a fast-rotating gaseous disk whose center possesses luminous stellar components or AGN providing weak feedback.