We used observations from the JWST Emission Line Survey (JELS) to measure the half-light radii (r₄) of 23 Hα-emitting star-forming (SF) galaxies at z=6. 1 in the PRIMER/COSMOS field. Galaxy sizes were measured in JWST Near-infrared Camera observations in rest-frame Hα (tracing recent star formation) with the F466N and F470N narrowband filters from JELS, and compared against rest-R-band, V-band (tracing established stellar populations) and near-ultraviolet sizes. We find a size-stellar mass (r₄-M*) relationship with a slope that is consistent with literature values at lower redshifts, though offset to lower sizes. We observe a large scatter in r₄ at low stellar mass (M*<10^8. 4 M_) which we believe is the result of bursty star formation histories (SFHs) of SF galaxies at the Epoch of Reionization (EoR). We find that the stellar and ionised gas components are similar in size at z=6. 1. The evidence of already-established stellar components in these Hα emitters (HAEs) indicates previous episodes of star formation have occurred. As such, following other JELS studies finding our HAEs are undergoing a current burst of star formation, we believe our results indicate that SF galaxies at the end of the EoR have already experienced a bursty SFH. From our r₄-M* relationship, we find r₄, ₅₄₄₄ₖ=0. 760. 46 kpc for fixed stellar mass M*=10^9. 25 M_, which is in agreement with other observations and simulations of star forming galaxies in the literature. We find a close-pair (major) merger fraction of (f₌₀₉. ₌₄ₑ₆₄ₑ=0. 440. 22) f₌₄ₑ₆₄ₑ=0. 430. 11 for galaxy separations d25 kpc, which is in agreement with other z6 studies.
Stephenson et al. (Tue,) studied this question.