Galactic turbulence and paleoclimate variability

环绕双黑洞盘中的MRI湍流与α黏度：对引力波失相和吸积变异性的启示

MRI Turbulence versus $α$-Viscosity in Circumbinary Disks: Implications for Gravitational-Wave Dephasing and Accretion Variability

通过Athena++模拟对比环绕双黑洞盘的HD与MHD过程，发现MHD力矩更大、变异性更强，对引力波相移和吸积变异性的影响与α盘模型存在显著差异。

Variability in Active Galactic Nuclei from Propagating Turbulent Relativistic Jets

We use the Athena hydrodynamics code to model propagating two-dimensional relativistic jets as approximations to the growth of radio-loud active galactic nuclei for various input jet velocities and jet-to-ambient matter density ratios. Using results from these simulations we estimate the changing synchrotron emission by summing the fluxes from a vertical strip of zones behind the reconfinement shock, which is nearly stationary, and from which a substantial portion of the flux variability should arise. We explore a wide range of time scales by considering two light curves from each simulation; …

黑洞天气——中尺度上的混沌冷吸积：变率与运动学

BlackHoleWeather -- Chaotic cold accretion across the meso-scale: Variability and kinematics

通过三维流体动力学模拟，研究湍流驱动的混沌冷吸积（CCA）中尺度变率、径向输运和运动学，揭示黑洞吸积率分布和功率谱特征。

On the time variability of the star formation efficiency

A star formation efficiency per free fall time that evolves over the life time of giant molecular clouds (GMCs) may have important implications for models of supersonic turbulence in molecular clouds or for the relation between star formation rate and H2 surface density. We discuss observational data that could be interpreted as evidence of such a time variability. In particular, we investigate a recent claim based on measurements of H2 and stellar masses in individual GMCs. We show that this claim depends crucially on the assumption that H2 masses do not evolve over the life times of GMCs. We…

用三维多频磁流体动力学模拟研究活动星系核吸积盘紫外辐射区的X射线反响映射

Simulating X-ray Reverberation in the UV-Emitting Regions of Active Galactic Nuclei Accretion Disks with 3D Multi-Frequency Magnetohydrodynamic Simulations

本研究利用三维多频磁流体动力学模拟AGN盘紫外辐射区并注入硬X射线，发现盘湍流足以驱动紫外光变内禀变率，而硬X射线对紫外功率谱影响极小，仅在长时标上存在弱相关，表明硬X射线可能并非反响映射信号的主要驱动因素。

Vortical field amplification and particle acceleration at rippled shocks

Supernova Remnants (SNRs) shocks are believed to accelerate charged particles and to generate strong turbulence in the post-shock flow. From high-energy observations in the past decade, a magnetic field at SNR shocks largely exceeding the shock-compressed interstellar field has been inferred. We outline how such a field amplification results from a small-scale dynamo process downstream of the shock, providing an explicit expression for the turbulence back-reaction to the fluid whirling. The spatial scale of the $X-$ray rims and the short time-variability can be obtained by using reasonable par…