论文标题
Lyman-Alpha排放中的宇宙网络
The cosmic web in Lyman-alpha emission
论文作者
论文摘要
我们为Lyman-Alpha发射开发了一个全面的理论模型，从单个Lyman-Alpha发射器（LAES）到Lyman-Alpha Halos（LAHS），Lyman-Alpha Blobs（Labs）和Lyman-Alpha Blobs（Labs）和Lyman-Alpha丝（Lyman-Alpha丝（LAFS））。为此，我们使用蒙特卡洛辐射转移方法后处理高分辨率TNG50宇宙磁流体动力学模拟，以捕获Lyman-Alpha光子的谐振散射过程。我们构建了一个在扩散气体中的重组和碰撞的发射模型，包括附近AGN的辐射效应以及恒星种群提供的发射。我们的治疗包括一个有身体动机的灰尘模型，我们从经验上校准了观察到的LAE光度函数。然后，我们专注于$ z = 2 $ lyman-alpha宇宙网的可观察性和物理起源，研究了主要的发射机制和空间起源。我们发现，弥漫性lyman-alpha丝实际上是由产生的光子照明的，不是来自播层间介质本身，而是来自星系内及其气态光环。在我们的模型中，这种排放主要由中间质量晕圈（$ 10^{10} -10^{11} \，$ m $ _ {\ odot} $），主要是由于其近亲媒体和中央，年轻恒星种群中的碰撞激发。从观察上讲，我们对细丝中的丰度，面积，线性大小和嵌入的光环/发射极群体进行预测。采用同上表面亮度阈值$ 10^{ - 20} \，$ erg $ \，$ s $^{ - 1} \，$ cm $^{ - 2} \，$ arcsec $^{ - 2} $ cmpc $^{ - 3} \，$ for $ 400 \，$ pkpc的长度。鉴于足够大的调查足迹，对Lyman-Alpha Cosmic Web的检测已接触到现代积分田间光谱仪，包括Muse，Virus和KCWI。
We develop a comprehensive theoretical model for Lyman-alpha emission, from the scale of individual Lyman-alpha emitters (LAEs) to Lyman-alpha halos (LAHs), Lyman-alpha blobs (LABs), and Lyman-alpha filaments (LAFs) of the diffuse cosmic web itself. To do so, we post-process the high-resolution TNG50 cosmological magnetohydrodynamical simulation with a Monte Carlo radiative transfer method to capture the resonant scattering process of Lyman-alpha photons. We build an emission model incorporating recombinations and collisions in diffuse gas, including radiative effects from nearby AGN, as well as emission sourced by stellar populations. Our treatment includes a physically motivated dust model, which we empirically calibrate to the observed LAE luminosity function. We then focus on the observability, and physical origin, of the $z=2$ Lyman-alpha cosmic web, studying the dominant emission mechanisms and spatial origins. We find that diffuse Lyman-alpha filaments are, in fact, illuminated by photons which originate, not from the intergalactic medium itself, but from within galaxies and their gaseous halos. In our model, this emission is primarily sourced by intermediate mass halos ($10^{10} - 10^{11}\,$M$_{\odot}$), principally due to collisional excitations in their circumgalactic media as well as central, young stellar populations. Observationally, we make predictions for the abundance, area, linear size, and embedded halo/emitter populations within filaments. Adopting an isophotal surface brightness threshold of $10^{-20}\,$erg$\,$s$^{-1}\,$cm$^{-2}\,$arcsec$^{-2}$, we predict a volume abundance of Lyman-alpha filaments of ${\sim}10^{-3}$ cMpc$^{-3}\,$ for lengths above $400\,$pkpc. Given sufficiently large survey footprints, detection of the Lyman-alpha cosmic web is within reach of modern integral field spectrographs, including MUSE, VIRUS, and KCWI.
