%0 Generic %1 qin2021darkages %A Qin, Yuxiang %A Wyithe, J. Stuart B. %A Oesch, Pascal A. %A Illingworth, Garth D. %A Leonova, Ecaterina %A Mutch, Simon J. %A Naidu, Rohan P. %D 2021 %K library %T Dark-ages Reionization and Galaxy Formation Simulation XX. The Ly$\alpha$ IGM transmission properties and environment of bright galaxies during the Epoch of Reionization %U http://arxiv.org/abs/2108.03675 %X The highly neutral inter-galactic medium (IGM) during the Epoch of Reionization (EoR) is expected to suppress Ly$\alpha$ emission with damping-wing absorption, causing nearly no Ly$\alpha$ detection from star-forming galaxies at $z\sim8$. However, spectroscopic observations of the 4 brightest galaxies ($H_160\sim25$ mag) at these redshifts do reveal prominent Ly$\alpha$ line, suggesting locally ionised IGM. In this paper, we explore the Ly$\alpha$ IGM transmission and environment of bright galaxies during the EoR using the Meraxes semi-analytic model. We find brighter galaxies to be less affected by damping-wing absorption as they are effective at ionizing surrounding neutral hydrogen. Specifically, the brightest sources ($H_160łesssim25.5$ mag) lie in the largest ionized regions in our simulation, and have low attenuation of their Ly$\alpha$ from the IGM (optical depth $<1$). Fainter galaxies (25.5 mag$<H_160<27.5$ mag) have transmission that depends on UV luminosity, leading to a lower incidence of Ly$\alpha$ detection at fainter magnitudes. This luminosity-dependent attenuation explains why Ly$\alpha$ has only been observed in the brightest galaxies at $z\sim8$. Follow-up observations have revealed counterparts in the vicinity of these confirmed $z\sim8$ Ly$\alpha$ emitters. The environments of our modelled analogues agree with these observations in the number of nearby galaxies, which is a good indicator of whether Ly$\alpha$ can be detected among fainter galaxies. At the current observational limit, galaxies with $\ge2$--5 neighbours within $2'\times2'$ are $\sim2$--3 times more likely to show Ly$\alpha$ emission. JWST will discover an order of magnitude more neighbours, revealing $\gtrsim50$ galaxies in the largest ionizing bubbles and facilitating direct study of reionization morphology.

@misc{qin2021darkages, abstract = {The highly neutral inter-galactic medium (IGM) during the Epoch of Reionization (EoR) is expected to suppress Ly$\alpha$ emission with damping-wing absorption, causing nearly no Ly$\alpha$ detection from star-forming galaxies at $z{\sim}8$. However, spectroscopic observations of the 4 brightest galaxies (${\rm H}_{160}{\sim}25$ mag) at these redshifts do reveal prominent Ly$\alpha$ line, suggesting locally ionised IGM. In this paper, we explore the Ly$\alpha$ IGM transmission and environment of bright galaxies during the EoR using the Meraxes semi-analytic model. We find brighter galaxies to be less affected by damping-wing absorption as they are effective at ionizing surrounding neutral hydrogen. Specifically, the brightest sources (${\rm H}_{160}{\lesssim}25.5$ mag) lie in the largest ionized regions in our simulation, and have low attenuation of their Ly$\alpha$ from the IGM (optical depth ${<}1$). Fainter galaxies (25.5 mag${<}{\rm H}_{160}{<}27.5$ mag) have transmission that depends on UV luminosity, leading to a lower incidence of Ly$\alpha$ detection at fainter magnitudes. This luminosity-dependent attenuation explains why Ly$\alpha$ has only been observed in the brightest galaxies at $z{\sim}8$. Follow-up observations have revealed counterparts in the vicinity of these confirmed $z{\sim}8$ Ly$\alpha$ emitters. The environments of our modelled analogues agree with these observations in the number of nearby galaxies, which is a good indicator of whether Ly$\alpha$ can be detected among fainter galaxies. At the current observational limit, galaxies with ${\ge}2$--5 neighbours within $2'{\times}2'$ are ${\sim}2$--3 times more likely to show Ly$\alpha$ emission. JWST will discover an order of magnitude more neighbours, revealing ${\gtrsim}50$ galaxies in the largest ionizing bubbles and facilitating direct study of reionization morphology.}, added-at = {2021-08-10T08:33:47.000+0200}, author = {Qin, Yuxiang and Wyithe, J. Stuart B. and Oesch, Pascal A. and Illingworth, Garth D. and Leonova, Ecaterina and Mutch, Simon J. and Naidu, Rohan P.}, biburl = {https://www.bibsonomy.org/bibtex/24357281a709ac2df444d013069028691/gpkulkarni}, description = {Dark-ages Reionization and Galaxy Formation Simulation XX. The Ly$\alpha$ IGM transmission properties and environment of bright galaxies during the Epoch of Reionization}, interhash = {32311faac76290a69b497630357ce105}, intrahash = {4357281a709ac2df444d013069028691}, keywords = {library}, note = {cite arxiv:2108.03675Comment: 10 pages, 3 figures, submitted to MNRAS, comments are welcome}, timestamp = {2021-08-10T08:33:47.000+0200}, title = {Dark-ages Reionization and Galaxy Formation Simulation XX. The Ly$\alpha$ IGM transmission properties and environment of bright galaxies during the Epoch of Reionization}, url = {http://arxiv.org/abs/2108.03675}, year = 2021 }