Hα emission in the outskirts of galaxies at<i>z</i>= 0.4

This paper reports detections of H$\alpha$ emission and stellar continuum out to approximately 30 physical kpc, directionality in the outskirts H$\alpha$-emitting galaxies (H$\alpha$ emitters) at $z=0.4$. research adopts narrow-band selected emitters $z=0.4$ from emission-line object catalog by Hayashi et al. (2020), which is based on data Deep Ultradeep layers Hyper Suprime-Cam Subaru Strategic Program. narrow- broad-band images 8625 across 16.8 deg$^2$ enable us construct deep composite images. The stacked show diffuse (down $\sim5\times10^{-20}$ erg~s$^{-1}$cm$^{-2}$arcsec$^{-2}$) $\sim5\times10^{-22}$ erg~s$^{-1}$cm$^{-2}$A$^{-1}$arcsec$^{-2}$), extending beyond 10 kpc masses $>10^9$ M$_\odot$, parts may originate halos. Those radial profiles are broadly consistent with each other. In addition, we obtain a dependence position angle because relatively higher equivalent width has been detected along minor-axis towards galaxy disks. While could be attributed biconical outflows, further hydrodynamic simulations highly demanded pin down exact cause.