Takashi MURAYAMA
(Tohoku University)
We present morphological properties of Lya emitters (LAEs) at z~4.9 in the COSMOS field, based on HST/ACS data. The ACS imaging in the F814W (I814) filter covered 61 LAEs of the 79 LAEs identified in the full two square degree field, and 55 LAEs of them are detected in the ACS images. By comparing with Subaru Suprim-cam i’, z’, and NB711, we found that I814 mainly probes UV continuum of LAEs. For 8 LAEs among them, double ACS sources are detected. Separation between the double sources ranges ~0.4”-0.9”. Half-light radii (RHL) of most LAEs are grater than the PSF size. However, there is no widely extended LAE with RHL > 0.4”). In the diagram of ellipticity vs RHL, we found that extended LAEs tend to have a moderately large ellipticity. This is at least partly explained by double source LAEs with a small separation that are detected as a single elongated source. There are probably more double source LAEs than we found. Comparison of LAEs with LBGs at high redshifts indicates little difference of size unlike the previous study.