Most diffuse baryons, including the circumgalactic medium (CGM) surrounding galaxies and the intergalactic medium (IGM) in the cosmic web, remain unmeasured and unconstrained. Fast radio bursts (FRBs) offer an unparalleled method to measure the electron dispersion measures (DMs) of ionized baryons. Their distribution can resolve the missing baryon problem and constrain the history of feedback theorized to impart significant energy to the CGM and IGM. We analyze the Cosmology and Astrophysics with Machine Learning Simulations using three suites, IllustrisTNG, SIMBA, and Astrid, each varying six parameters (two cosmological and four astrophysical feedback), for a total of 183 distinct simulation models. We find significantly different predictions between the fiducial models of the suites owing to their different implementations of feedback. SIMBA exhibits the strongest feedback, leading to the smoothest distribution of baryons and reducing the sight-line-to-sight-line variance in DMs between z = 0 and 1. Astrid has the weakest feedback and the largest variance. We calculate FRB CGM measurements as a function of galaxy impact parameter, with SIMBA showing the weakest DMs due to aggressive active galactic nucleus (AGN) feedback and Astrid the strongest. Within each suite, the largest differences are due to varying AGN feedback. IllustrisTNG shows the most sensitivity to supernova feedback, but this is due to the change in the AGN feedback strengths, demonstrating that black holes, not stars, are most capable of redistributing baryons in the IGM and CGM. We compare our statistics directly to recent observations, paving the way for the use of FRBs to constrain the physics of galaxy formation and evolution.

中文翻译：

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用快速射电爆发探测环绕银河系介质：来自 CAMELS 的见解


大多数弥散重子，包括星系周围的环星系介质（CGM）和宇宙网中的星系间介质（IGM），仍然无法测量和不受约束。快速射电爆发 (FRB) 提供了一种无与伦比的方法来测量电离重子的电子色散测量 (DM)。它们的分布可以解决重子缺失问题，并限制反馈的历史理论，从而向 CGM 和 IGM 传递大量能量。我们使用三个套件（IllustrisTNG、SIMBA 和 Astrid）通过机器学习模拟来分析宇宙学和天体物理学，每个套件有六个不同的参数（两个宇宙学和四个天体物理反馈），总共 183 个不同的模拟模型。我们发现由于反馈实现的不同，套件的基准模型之间的预测存在显着差异。 SIMBA 表现出最强的反馈，导致重子分布最平滑，并减少 z = 0 和 1 之间 DM 中的视线到视线方差。Astrid 的反馈最弱，方差最大。我们将 FRB CGM 测量值计算为星系撞击参数的函数，其中 SIMBA 显示出由于积极的活动星系核 (AGN) 反馈而导致的最弱的 DM，而 Astrid 的 DM 最强。在每个套件中，最大的差异是由于 AGN 反馈的不同而造成的。 IllustrisTNG 显示出对超新星反馈最敏感，但这是由于 AGN 反馈强度的变化所致，这表明黑洞（而不是恒星）最有能力在 IGM 和 CGM 中重新分配重子。我们将我们的统计数据直接与最近的观测结果进行比较，为使用快速射电暴来约束星系形成和演化的物理学铺平了道路。