SILVERRUSH. XII. Intensity Mapping for Ly? Emission Extending over 100–1000 Comoving Kpc around z ? 2?7 LAEs with Subaru HSC-SSP and CHORUS Data

We conduct intensity mapping to probe for extended diffuse Ly$\alpha$ emission around emitters (LAEs) at $z\sim2-7$, exploiting very deep ($\sim26$ mag $5\sigma$) and large-area ($\sim4.5$ deg$^2$) Subaru/Hyper Suprime-Cam narrow-band (NB) images large LAE catalogs consisting of a total 1781 LAEs $z=2.2$, $3.3$, $5.7$, $6.6$ obtained by the HSC-SSP SILVERRUSH CHORUS projects. calculate spatial correlations these with $\sim1-2$ billion pixel flux values NB images, deriving average surface brightness (${\rm SB_{Ly\alpha}}$) radial profiles LAEs. By carefully estimating systematics such as fluctuations sky background point spread functions, we detect ($\sim10^{-20}-10^{-19}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$) $100-1000$ comoving kpc $z=3.3$ $4.1\sigma$ level tentatively ($\sim2\sigma$) other redshifts, beyond virial radius dark-matter halo mass $10^{11}\ M_\odot$. While observed ${\rm SB_{Ly\alpha}}$ have similar amplitudes $z=2.2-6.6$ within uncertainties, intrinsic (corrected cosmological dimming effect) increase toward high redshifts. This trend may be explained increasing hydrogen gas density due evolution cosmic volume. Comparisons theoretical models suggest that is powered resonantly scattered photons in CGM IGM originates from inner part LAE, and/or neighboring galaxies LAE.