Modelling of Lyman-alpha emitting galaxies and ionized bubbles at the epoch of reionization
Modelling of Lyman-alpha emitting galaxies and ionized bubbles at the epoch of reionization
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DOI：
10.1093/mnras/sty997
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发表时间：
2017-01
影响因子：
4.8
通讯作者：
H. Yajima;K. Sugimura;Kenji Hasegawa Tohoku University;Nagoya University
中科院分区：
文献类型：
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作者：
H. Yajima;K. Sugimura;Kenji Hasegawa Tohoku University;Nagoya University
了解发光星系(LAE)可能是揭示早期宇宙中宇宙再电离和星系形成的关键。基于晕合并树和Ly$-α辐射传输计算，我们模拟了LaE的红移演化及其在6$处的观测性质。我们考虑了与单个LaE有关的电离气泡和Ly$\α$光子的IGM传输。结果表明，Lyα光度与晕质量和恒星质量密切相关，而与恒星形成率的关系具有较大的离散性。将我们的模型与Konno等人的观测光度函数进行了比较，我们认为在zsim 7$的LaE的星系风为Vrm Out，S的星系风为Nrm HI，HI柱密度为NrmHi，HI柱密度为NrmHi。由于较低的恒星形成率和较小的HII气泡，亮激光的数密度随着红移的增加而迅速下降。我们的模型预测，未来使用JWST、E-ELT和TMT等下一代望远镜进行大范围的深部探测，可以探测到$z\sim 10$的LAE，数密度为$n\rM LAE}\sim{\rM a~(-6)\\rm MPC^-3}$，通量灵敏度$10^{-18}~\rm erg，cm^-2}\，S^-1}$。通过将这些观测与未来21厘米的观测相结合，有可能探测到带有$L_{Ly\α}\gtrsim 10^{42}~\rmerg~S^-1的LAE和与之相关的大小为$z\sim 10$的巨型HII气泡。
Understanding Ly$\alpha$ emitting galaxies (LAEs) can be a key to reveal cosmic reionization and galaxy formation in the early Universe. Based on halo merger trees and Ly$\alpha$ radiation transfer calculations, we model redshift evolution of LAEs and their observational properties at $z \ge 6$. We consider ionized bubbles associated with individual LAEs and IGM transmission of Ly$\alpha$ photons. We find that Ly$\alpha$ luminosity tightly correlates with halo mass and stellar mass, while the relation with star formation rate has a large dispersion. Comparing our models with the observed luminosity function by Konno et al., we suggest that LAEs at $z \sim 7$ have galactic wind of $V_{\rm out} \gtrsim 100~\rm km\, s^{-1}$ and HI column density of $N_{\rm HI} \gtrsim 10^{20}~\rm cm^{-2}$. Number density of bright LAEs rapidly decreases as redshift increases, due to both lower star formation rate and smaller HII bubbles. Our model predicts future wide deep surveys with next generation telescopes, such as JWST, E-ELT and TMT, can detect LAEs at $z \sim 10$ with a number density of $n_{\rm LAE} \sim {\rm a~few~} \times10^{-6} ~\rm Mpc^{-3}$ for the flux sensitivity of $10^{-18} ~\rm erg\, cm^{-2}\, s^{-1}$. By combining these surveys with future 21-cm observations, it could be possible to detect both LAEs with $L_{Ly\alpha} \gtrsim 10^{42}~\rm erg~s^{-1}$ and their associated giant HII bubbles with the size $\gtrsim 250 ~\rm kpc$ at $z \sim 10$.