The Lyman alpha (LyA) line of neutral hydrogen plays a central role in observations of star-forming galaxies. However, resonant scattering makes it difficult to directly interpret LyA signatures. Monte Carlo radiative transfer (MCRT) calculations have become the gold standard for modeling LyA, but it becomes extremely computationally expensive in optically thick environments. Workarounds, such as core-skipping to avoid repetitive low-transport scatterings, greatly increase the efficiency of MCRT simulations but introduce errors in the solutions. While core-skipping is designed to preserve emergent spectra, the internal radiation field, most importantly, the momentum imparted, is not properly preserved. On the other hand, to make analytical and numerical progress, it is often assumed that photons diffuse in both frequency and physical space. We find that these diffusion approximations break down for frequencies near the core and positions at finite optical depths. We propose a more physically-motivated definition for the core-wing transition frequency to isolate such effects. We derive new spectral distributions of internal radiation properties and compare the results with simulations. We analyze the diffusive properties of LyA photons and demonstrate anomalous spatial diffusion behavior with fat-tailed distributions. This work deepens our understanding of diffusion in resonant-line transfer and identifies areas where simulations or analytics may be failing and how these failures may be resolved.
Power-law Emission-line Wings and Radiation-Driven Superwinds in Local Lyman Continuum Emitters
University of Michigan(密歇根大学);University of Geneva(日内瓦大学);Space Telescope Science Institute(太空望远镜科学研究所);Stockholm University(斯德哥尔摩大学);University of Minnesota(明尼苏达大学);Arizona State University(亚利桑那州立大学);Zhejiang University(浙江大学);University of Texas at Austin(得克萨斯大学奥斯汀分校);Laboratory for Atmospheric and Space Physics(大气与空间物理实验室);University of Edinburgh(爱丁堡大学);University of Massachusetts Amherst(马萨诸塞大学阿默斯特分校);Johns Hopkins University(约翰斯·霍普金斯大学);Williams College(威廉姆斯学院);University of Virginia(弗吉尼亚大学);Northwestern University(西北大学)
Constraints on the $z\sim6-13$ intergalactic medium from JWST spectroscopy of Lyman-alpha damping wings in galaxies
Cosmic Dawn Center (DAWN)(黎明宇宙中心);Niels Bohr Institute, University of Copenhagen(哥本哈根大学尼尔斯·玻尔研究所);Steward Observatory, University of Arizona(亚利桑那大学斯图尔德天文台);Department of Astronomy, University of California, Berkeley(加州大学伯克利分校天文学系)
High Precision Analyses of Lyman alpha Damping Wing of Gamma-Ray Bursts in the Reionization Era: On the Controversial Results from GRB 130606A at z = 5.91
Swift GRB 130606 A在z = 5.91处的空前明亮的余辉给我们提供了一个通过高精度分析Ly α吸收的红阻尼翼来探测再电离时代的独特机会,但不同望远镜观测到的光谱对星系际介质(IGM)中中性氢分数(fHI)的限制是矛盾的。在这里,我们研究的起源,这种差异进行分析的频谱VLT与我们自己的分析代码以前用于适应斯巴鲁频谱。虽然VLT团队没有报告使用VLT光谱的IGM HI的证据,但我们证实了我们之前的结果,即更喜欢非零IGM HI(当IGM HI扩展到GRB红移时,最佳拟合f_HI ~ 0.06)。不含IGM HI的模型的VLT光谱拟合残差显示出与斯巴鲁光谱相同的系统趋势。我们认为,两个小组之间的差异可能是由于配件所采用的波长范围不同;我们的波长范围比VLT团队的更宽,而且我们避免了深Ly α吸收的最短波长范围(lambda_obs < 8426 A),因为这一区域主要由宿主星系中的HI控制,并且宿主星系HI速度分布的系统不确定性很大。我们还研究了这些结果的灵敏度,通过Ly α截面公式,从经典的洛伦兹函数到最近的一个考虑到完全量子力学散射。研究发现,对非零IGM HI的偏好对截面公式的选择是稳健的,但它在定量上是不可忽略的,因此在未来的分析中应该小心。
Characterizing Lyman alpha emission from high-redshift galaxies
Scuola Normale Superiore di Pisa(比萨高等师范学院);University of Catania(卡塔尼亚大学);Centro Nazionale “High Performance Computing, Big Data and Quantum Computing”(高性能计算、大数据和量子计算国家中心);Cosmic Dawn Center (DAWN)(宇宙黎明中心);Niels Bohr Institute, University of Copenhagen(哥本哈根大学尼尔斯·玻尔研究所)
Characterising Ly$α$ damping wings at the onset of reionisation: Evidence for highly efficient star formation driven by dense, neutral gas in UV-bright galaxies at $z>9$
Cosmic Dawn Center (DAWN)(宇宙黎明中心);Niels Bohr Institute, University of Copenhagen(哥本哈根大学尼尔斯·玻尔研究所);DTU Space, Technical University of Denmark(丹麦技术大学空间研究所);Institute for Computational Cosmology, Department of Physics, Durham University(杜伦大学物理学院计算宇宙学研究所);David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto(多伦多大学大卫·A·邓普林天文与天体物理系)
A faint M$_{\rm UV} = -14.5$ Lyman-continuum leaker candidate in the epoch of reionization: Unprecedented Ly$α$ properties at z=5.725
INAF – OAS, Osservatorio di Astrofisica e Scienza dello Spazio di Bologna(意大利国家天体物理研究所 - 博洛尼亚天文与空间科学观测站);IPAC, California Institute of Technology(加州理工学院 IPAC);Astronomical Institute, Tohoku University(东北大学天文学研究所);Space Telescope Science Institute (STScI)(太空望远镜科学研究所);Department of Physics and Astronomy, University of California, Los Angeles(加州大学洛杉矶分校物理与天文学系);MIT Kavli Institute for Astrophysics and Space Research(麻省理工学院卡弗里天体物理与空间研究研究所);Max-Planck-Institut für Astrophysik(马克斯·普朗克天体物理研究所);Univ Lyon, Univ Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophy(里昂大学、里昂第一大学、巴黎高等师范学校里昂校区、法国国家科学研究中心、天体物理研究中心)
Impact of Resonance, Raman, and Thomson Scattering on Hydrogen Line Formation in Little Red Dots
Max-Planck-Institut für Astrophysik(马克斯·普朗克天体物理研究所);Astronomisches Rechen-Institut, Zentrum für Astronomie, Universität Heidelberg(海德堡大学天文计算中心);Institute of Science and Technology Austria (ISTA)(奥地利科学技术研究院);Cosmic Dawn Center (DAWN)(宇宙黎明中心);Niels Bohr Institute, University of Copenhagen(哥本哈根大学尼尔斯·玻尔研究所)