We model the time dependent radio emission from a disk accretion event in a T-Tauri star using 3D, ideal magnetohydrodynamic simulations combined with a gyrosynchrotron emission and radiative transfer model. We predict for the first time, the multi-frequency (1$-$1000 GHz) intensity and circular polarisation from a flaring T-Tauri star. A flux tube, connecting the star with its circumstellar disk, is populated with a distribution of non-thermal electrons which is allowed to decay exponentially after a heating event in the disk and the system is allowed to evolve. The energy distribution of the electrons, as well as the non-thermal power law index and loss rate, are varied to see their effect on the overall flux. Spectra are generated from different lines of sight, giving different views of the flux tube and disk. The peak flux typically occurs around 20$-$30 GHz and the radio luminosity is consistent with that observed from T-Tauri stars. For all simulations, the peak flux is found to decrease and move to lower frequencies with elapsing time. The frequency-dependent circular polarisation can reach 10$-$30$\%$ but has a complex structure which evolves as the flare evolves. Our models show that observations of the evolution of the spectrum and its polarisation can provide important constraints on physical properties of the flaring environment and associated accretion event.

中文翻译：

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通过 MHD 模拟对 T-Tauri 星进行预测，预测无线电发射的时间变化

我们使用 3D、理想的磁流体动力学模拟结合陀螺同步加速器发射和辐射传递模型，对来自 T-Tauri 星盘吸积事件的时间相关无线电发射进行建模。我们首次预测了一颗闪耀的金牛座恒星的多频（1$-$1000 GHz）强度和圆极化。将恒星与其星周盘连接起来的通量管中布满了非热电子分布，在盘中发生加热事件后，非热电子允许按指数衰减，并且允许系统演化。电子的能量分布以及非热幂律指数和损失率会发生变化，以查看它们对总通量的影响。光谱是从不同的视线产生的，给出了通量管和磁盘的不同视图。峰值通量通常出现在 20$-$30 GHz 左右，射电光度与从 T-Tauri 恒星观测到的光度一致。对于所有模拟，发现峰值通量随着时间的流逝而降低并移动到较低频率。与频率相关的圆极化可以达到 10$-$30$\%$，但具有随着耀斑演变而演变的复杂结构。我们的模型表明，对光谱演变及其极化的观察可以为燃烧环境和相关吸积事件的物理特性提供重要的约束。与频率相关的圆极化可以达到 10$-$30$\%$，但具有随着耀斑演变而演变的复杂结构。我们的模型表明，对光谱演变及其极化的观察可以为燃烧环境和相关吸积事件的物理特性提供重要的约束。与频率相关的圆极化可以达到 10$-$30$\%$，但具有随着耀斑演变而演变的复杂结构。我们的模型表明，对光谱演变及其极化的观察可以为燃烧环境和相关吸积事件的物理特性提供重要的约束。