SILVERRUSH. IX. Lya Intensity Mapping with Star-Forming Galaxies at z=5.7 and 6.6: A Possible Detection of Extended Lya Emission at $gtrsim$100 comoving kpc around and beyond the Virial-Radius Scale of Galaxy Dark Matter Halos. (arXiv:1906.00173v2 [astro-ph.GA] UPDATED)

SILVERRUSH. IX. Lya Intensity Mapping with Star-Forming Galaxies at z=5.7 and 6.6: A Possible Detection of Extended Lya Emission at $gtrsim$100 comoving kpc around and beyond the Virial-Radius Scale of Galaxy Dark Matter Halos. (arXiv:1906.00173v2 [astro-ph.GA] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Kakuma_R/0/1/0/all/0/1">Ryota Kakuma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ouchi_M/0/1/0/all/0/1">Masami Ouchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Harikane_Y/0/1/0/all/0/1">Yuichi Harikane</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ono_Y/0/1/0/all/0/1">Yoshiaki Ono</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Inoue_A/0/1/0/all/0/1">Akio K. Inoue</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Komiyama_Y/0/1/0/all/0/1">Yutaka Komiyama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kusakabe_H/0/1/0/all/0/1">Haruka Kusakabe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_C/0/1/0/all/0/1">Chien-Hsiu Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsuda_Y/0/1/0/all/0/1">Yuichi Matsuda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsuoka_Y/0/1/0/all/0/1">Yoshiki Matsuoka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mawatari_K/0/1/0/all/0/1">Ken Mawatari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Momose_R/0/1/0/all/0/1">Rieko Momose</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shibuya_T/0/1/0/all/0/1">Takatoshi Shibuya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Taniguchi_Y/0/1/0/all/0/1">Yoshiaki Taniguchi</a>

We present results of the cross-correlation Ly$alpha$ intensity mapping with
Subaru/Hyper Suprime-Cam (HSC) ultra-deep narrowband images and Ly$alpha$
emitters (LAEs) at $z=5.7$ and $6.6$ in a total area of $4$ deg$^2$. Although
overwhelming amount of data quality controls have been performed for the
narrowband images, we further conduct extensive analysis evaluating systematics
of large-scale point-spread-function wings, sky subtractions, and unknown
errors based on physically uncorrelated signals and sources found in real HSC
images and object catalogs, respectively. Removing the systematics, we
carefully calculate cross-correlations between Ly$alpha$ intensity of the
narrowband images and the LAEs. We tentatively identify very diffuse Ly$alpha$
emission with the $simeq 3sigma$ ($simeq 2sigma$) significance at $gtrsim$
100 comoving kpc (ckpc) far from the LAEs at $z=5.7$ ($6.6$), around and
probably even beyond a virial radius of star-forming galaxies with
$M_mathrm{h}sim10^{11}M_odot$. The diffuse Ly$alpha$ emission possibly
extends up to $1$,$000$ ckpc with the surface brightness of
$10^{-20}$-$10^{-19}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$. We confirm that the
small-scale ($<150$ ckpc) Ly$alpha$ radial profiles of LAEs are consistent
with those obtained by recent MUSE observations. Comparisons with numerical
simulations suggest that the large-scale ($sim150$-$1$,$000$ ckpc) Ly$alpha$
emission are not explained by unresolved faint neighboring galaxies including
satellites, but by a combination of Ly$alpha$ photons emitted from the central
LAE and other unknown sources, such as cold-gas streams and galactic outflow.
We find no evolution in the Ly$alpha$ radial profiles of our LAEs from $z=5.7$
to $6.6$, where theoretical models predict a flattening of the profile slope
made by cosmic reionization, albeit with our moderately large observational
errors.

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