Filamentary baryons and where to find them A forecast of synchrotron radiation from merger and accretion shocks in the local Cosmic Web
Filamentary baryons and where to find them A forecast of synchrotron radiation from merger and accretion shocks in the local Cosmic Web
复制标题
丝状重子以及在哪里可以找到它们本地宇宙网中合并和吸积激波产生的同步加速器辐射的预测
DOI：
10.1051/0004-6361/202140364
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发表时间：
2022
影响因子：
6.5
通讯作者：
Oei M
中科院分区：
文献类型：
--
作者：
Oei M
宇宙网中星系际介质（IGM）的同步辐射探测是检验天体物理学冲击物理模型及其辐射机制、追踪失踪重子和限制磁生成（河外磁场的起源和演化）的前沿课题。现在是时候发展一个严格的统计框架来预测天空区域的最强信号，并从单纯的检测到推理，也就是说，确定最合理的物理模型和参数值observations.MethodsCurrent理论假设，灯丝IGM点亮通过冲击，起源于大规模的结构形成。贝叶斯推理，我们产生了一个概率分布的一组特定的强度函数，代表我们的合并和吸积冲击同步加速器宇宙网（MASSCW）的看法。我们结合了贝叶斯起源重建从Galerkin（博格）斯隆数字巡天（SDSS）总物质密度后，这是基于光谱观测的星系内SDSS DR 7，恩佐磁流体力学（MHD）宇宙学模拟，高斯随机场（GRF）的快照，和射线追踪的方法来达到的结果。包括原则性的不确定性量化，对于四分之一的天空和宇宙学的redshiftzmax= 0.2。当前实现的超级Mpc 3D分辨率限制了预测的2D图像的分辨率，因此无法解决单个合并和吸积冲击。MASSCW先验可用于确定低频射电望远镜最有希望瞄准的区域，并进行实际探测实验。我们还计算了MASSCW信号的通量密度加权平均（即天空平均）红移的概率分布，并发现中值为。我们构建了一个低参数分析模型，该模型产生了类似的分布，中位数为。外推模型，我们能够计算宇宙中的所有大尺度结构（包括超过zmax的结构），并表明，如果只考虑细丝，它实际上取决于一个参数。作为案例研究，我们最后探索了我们的MASSCW特定强度函数在三个星系团附近的预测，武仙座星系团，后发座星系团，和阿贝尔2199，以及在三个深低频阵列（LOFAR）高频阵列（HBA）领域，洛克曼洞，阿贝尔2255，和大熊座超星系团。和原则性的框架，用于预测低频，低分辨率的特定强度函数的宇宙网络由于合并和吸积冲击，在大规模的结构形成。这些预测指导了本地宇宙在北方天空的一半寻找超重子。一旦替代发射机制的宇宙学模拟已经成熟，我们的方法可以扩展到预测其他物理路径，有助于难以捉摸的同步加速器宇宙网络信号。
ContextThe detection of synchrotron radiation from the intergalactic medium (IGM) that pervades the filaments of the Cosmic Web constitutes an upcoming frontier to test physical models of astrophysical shocks and their radiation mechanisms, trace the missing baryons, and constrain magnetogenesis – the origin and evolution of extragalactic magnetic fields.AimsThe first synchrotron detections of the IGM within filaments have recently been claimed. Now is the time to develop a rigorous statistical framework to predict sky regions with the strongest signal and to move from mere detection to inference, that is to say identifying the most plausible physical models and parameter values from observations.MethodsCurrent theory posits that the filament IGM lights up through shocks that originate from large-scale structure formation. With Bayesian inference, we generated a probability distribution on the set of specific intensity functions that represent our view of the merger- and accretion-shocked synchrotron Cosmic Web (MASSCW). We combined the Bayesian Origin Reconstruction from Galaxies (BORG) Sloan Digital Sky Survey (SDSS) total matter density posterior, which is based on spectroscopic observations of galaxies within SDSS DR7, snapshots of Enzo magnetohydrodynamics (MHD) cosmological simulations, a Gaussian random field (GRF), and a ray tracing approach to arrive at the result.ResultsWe present a physics-based prediction of the MASSCW signal, including principled uncertainty quantification, for a quarter of the sky and up to cosmological redshiftzmax= 0.2. The super-Mpc 3D resolution of the current implementation limits the resolution of the predicted 2D imagery, so that individual merger and accretion shocks are not resolved. The MASSCW prior can be used to identify the most promising fields to target with low-frequency radio telescopes and to conduct actual detection experiments. We furthermore calculated a probability distribution for the flux-density–weighted mean (i.e. sky-averaged) redshift of the MASSCW signal up tozmax, and found a median of . We constructed a low-parametric analytic model that produces a similar distribution for , with a median of . Extrapolating the model, we were able to calculate for all large-scale structure in the Universe (including what lies beyondzmax) and show that, if one only considers filaments, depends on virtually one parameter. As case studies, we finally explore the predictions of our MASSCW specific intensity function prior in the vicinity of three galaxy clusters, the Hercules Cluster, the Coma Cluster, and Abell 2199, and in three deep Low-frequency Array (LOFAR) High-band Antennae (HBA) fields, the Lockman Hole, Abell 2255, and the Ursa Major Supercluster.ConclusionsWe describe and implement a novel, flexible, and principled framework for predicting the low-frequency, low-resolution specific intensity function of the Cosmic Web due to merger and accretion shocks that arise during large-scale structure formation. The predictions guide Local Universe searches for filamentary baryons through half of the Northern Sky. Once cosmological simulations of alternative emission mechanisms have matured, our approach can be extended to predict additional physical pathways that contribute to the elusive synchrotron Cosmic Web signal.