小红点：直接坍缩黑洞形成星系
Little Red Dots are Direct-Collapse Black Hole-Forming Galaxies
- Institute of Cosmology and Gravitation, Portsmouth University（宇宙学与引力研究所，朴茨茅斯大学）
- Physics Department, College of Science, United Arab Emirates University（物理系，科学学院，阿联酋大学）
- Department of Physics, Aristotle University of Thessaloniki（物理系，塞萨洛尼基亚里士多德大学）
- Institute for Astronomy, University of Edinburgh（天文学研究所，爱丁堡大学）
- Center for Astrophysics, Harvard and Smithsonian（天体物理学中心，哈佛大学和史密森尼学会）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过宇宙学模拟证明，红移4-9的“小红点”是直接坍缩黑洞星系，其光谱特征由致密盘遮蔽黑洞产生，模型成功再现了多种观测光谱。
AI中文摘要：
在$4 < z < 8$红移范围内的“小红点”（LRDs）是JWST迄今最具挑战性的发现之一，因为它们独特的V形光谱和致密形态（100-200 pc）违背了传统的天体物理解释。先前试图将LRDs解释为致密恒星系统、具有差异流动的重包裹黑洞、超大质量恒星或更奇特的“黑洞恒星”等天体的尝试，要么无法展示它们如何形成，要么无法解释其光谱中吸收特征所需的致密壳层的起源，要么无法解释其观测到的丰度或推断的寿命。在这里，我们表明LRDs就是直接坍缩黑洞星系，其中黑洞仍被形成它的巨大盘所遮蔽。我们的宇宙学模拟产生的光谱与LRDs的光谱高度匹配，因为盘中心的高密度捕获了来自黑洞的X射线，并产生了观测到的巴尔默吸收特征，同时允许紫外、光学和再处理的红外通量部分逃逸。宿主星系在黑洞旁边形成了一个致密的10$^8$ M$_{\odot}$恒星团，半径150 pc，与LRDs的观测结果一致。我们的模型再现了各种LRD光谱，从典型天体如红移$z = 5.28$的RUBIES-EGS-42046，到具有最强巴尔默断裂的天体如红移$z = 7.76$的MoM-BH$^*$-1，以及最高红移的天体如红移$z = 9.29$的CAPERS-LRD-z9。
英文摘要：
"Little Red Dots" (LRDs) at $4 < z < 8$ are one of the most challenging discoveries by JWST to date because their distinctive V-shaped spectra and compact morphologies (100 - 200 pc) defy conventional astrophysical interpretation. Previous attempts to explain LRDs as compact stellar systems, heavily-cocooned black holes with differential flows, supermassive stars, or more exotic objects like 'black-hole stars' either cannot show how they formed, explain the origin of the dense shells needed for the absorption features in their spectra, or account for their observed abundances or inferred lifetimes. Here we show that LRDs are simply direct-collapse black hole galaxies in which the BH is still shrouded by the massive disk that created it. Our cosmological simulations yield spectra that are good matches to those of LRDs because high densities at the center of the disk trap X-rays from the BH and produce the observed Balmer absorption features while allowing UV, optical and reprocessed IR flux to partly escape. The host galaxy forms a dense 10$^8$ M$_{\odot}$ cluster of stars with a radius of 150 pc next to the BH, consistent with observations of LRDs. Our models reproduce a wide variety of LRD spectra from typical objects like RUBIES-EGS-42046 at $z = 5.28$ to those with the strongest Balmer breaks such as MoM-BH$^*$-1 at $z = 7.76$ and those at the highest redshifts like CAPERS-LRD-z9 at $z = 9.29$.
