Statistical correlation between the distribution of Ly$alpha$ emitters and IGM HI at $zsim2.2$ mapped by Subaru/Hyper Suprime-Cam. (arXiv:2008.01733v1 [astro-ph.GA])

Statistical correlation between the distribution of Ly$alpha$ emitters and IGM HI at $zsim2.2$ mapped by Subaru/Hyper Suprime-Cam. (arXiv:2008.01733v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Liang_Y/0/1/0/all/0/1">Yongming Liang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kashikawa_N/0/1/0/all/0/1">Nobunari Kashikawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cai_Z/0/1/0/all/0/1">Zheng Cai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fan_X/0/1/0/all/0/1">Xiaohui Fan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Prochaska_J/0/1/0/all/0/1">J. Xavier Prochaska</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shimasaku_K/0/1/0/all/0/1">Kazuhiro Shimasaku</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tanaka_M/0/1/0/all/0/1">Masayuki Tanaka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Uchiyama_H/0/1/0/all/0/1">Hisakazu Uchiyama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ito_K/0/1/0/all/0/1">Kei Ito</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shimakawa_R/0/1/0/all/0/1">Rhythm Shimakawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nagamine_K/0/1/0/all/0/1">Kentaro Nagamine</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shimizu_I/0/1/0/all/0/1">Ikkoh Shimizu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Onoue_M/0/1/0/all/0/1">Masafusa Onoue</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Toshikawa_J/0/1/0/all/0/1">Jun Toshikawa</a>

The correlation between neutral Hydrogen (HI) in the intergalactic medium
(IGM) and galaxies now attracts great interests. We select four fields which
include several coherently strong Ly$alpha$ absorption systems at $zsim2.2$
detected by using background quasars from the whole SDSS/(e)BOSS database. Deep
narrow-band and $g$-band imaging are performed using the Hyper Suprime-Cam on
the Subaru Telescope. We select out 2,642 Ly$alpha$ emitter (LAE) candidates
at $z=2.177pm0.023$ down to the Ly$alpha$ luminosity of
$L_{text{Ly}alpha}approx 2 times 10^{42} {rm erg~s}^{-1}$ to construct the
galaxy overdensity maps, covering an effective area of 5.39 deg$^2$. Combining
the sample with the Ly$alpha$ absorption estimated from 64 (e)BOSS quasar
spectra, we find a moderate to strong correlation between the LAE overdensity
$delta_{rm LAE}$ and the effective optical depth $tau_{rm LoS}$ in
line-of-sights, with $P$-value$=0.09%$ ($<0.01%$) when the field that
contains a significant quasar overdensity is in(ex)cluded. The
cross-correlation analysis also clearly suggests that up to $4pm1$ pMpc, LAEs
tend to cluster in the regions rich in HI gas, indicated by the high $tau_{rm
LoS}$, and avoid the low $tau_{rm LoS}$ region where the HI gas is deficient.
By averaging the $tau_{rm LoS}$ as a function of the projected distance ($d$)
to LAEs, we find a $30%$ excess signal at $2sigma$ level at $d<200$ pkpc,
indicating the dense HI in circumgalactic medium, and a tentative excess at
$400<d<600$ pkpc in IGM regime, corroborating the cross-correlation signal
detected at about $0.5$ pMpc. These statistical analyses indicate that
galaxy$-$IGM HI correlations exist on scales ranging from several hundred pkpc
to several pMpc at $zsim2.2$.

The correlation between neutral Hydrogen (HI) in the intergalactic medium
(IGM) and galaxies now attracts great interests. We select four fields which
include several coherently strong Ly$alpha$ absorption systems at $zsim2.2$
detected by using background quasars from the whole SDSS/(e)BOSS database. Deep
narrow-band and $g$-band imaging are performed using the Hyper Suprime-Cam on
the Subaru Telescope. We select out 2,642 Ly$alpha$ emitter (LAE) candidates
at $z=2.177pm0.023$ down to the Ly$alpha$ luminosity of
$L_{text{Ly}alpha}approx 2 times 10^{42} {rm erg~s}^{-1}$ to construct the
galaxy overdensity maps, covering an effective area of 5.39 deg$^2$. Combining
the sample with the Ly$alpha$ absorption estimated from 64 (e)BOSS quasar
spectra, we find a moderate to strong correlation between the LAE overdensity
$delta_{rm LAE}$ and the effective optical depth $tau_{rm LoS}$ in
line-of-sights, with $P$-value$=0.09%$ ($<0.01%$) when the field that
contains a significant quasar overdensity is in(ex)cluded. The
cross-correlation analysis also clearly suggests that up to $4pm1$ pMpc, LAEs
tend to cluster in the regions rich in HI gas, indicated by the high $tau_{rm
LoS}$, and avoid the low $tau_{rm LoS}$ region where the HI gas is deficient.
By averaging the $tau_{rm LoS}$ as a function of the projected distance ($d$)
to LAEs, we find a $30%$ excess signal at $2sigma$ level at $d<200$ pkpc,
indicating the dense HI in circumgalactic medium, and a tentative excess at
$400<d<600$ pkpc in IGM regime, corroborating the cross-correlation signal
detected at about $0.5$ pMpc. These statistical analyses indicate that
galaxy$-$IGM HI correlations exist on scales ranging from several hundred pkpc
to several pMpc at $zsim2.2$.

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