标题： 金牛座T型变星双星系统V773 Tau A的同步辐射 显示英文标题

标题： Synchrotron emission from the T Tauri binary system V773 Tau A

摘要： 前主序双星系统V773 Tau A在近日点通过时表现出显著的耀发活动。 在这里，我们展示了使用Plateau de Bure干涉仪在3毫米（90千兆赫）波长下观测到的这种耀发。 我们研究了导致该耀发衰减时间尺度为2.3小时的能量损失的不同可能原因。 我们排除了同步辐射、碰撞和逆康普顿损失，因为它们与观测限制不一致，并提出耀发的减弱可能是由于电子在磁结构的两个镜像点之间的每次反射时泄漏造成的，这些镜像点部分捕获了电子。 与我们的泄漏模型和先前观测结果兼容的磁结构是头盔羽状物，就像在太阳情况下一样，它可以发生在其中一个恒星发出X射线的星冠环顶部。 羽状物可能延伸至20倍半径，并在近日点通过时与另一颗恒星的星冠相互作用，导致反复耀发。 头盔羽状物的两个镜像点处推断出的磁场强度范围为0.12-125高斯，相应地，部分被捕获电子的洛伦兹因子γ范围为20<γ<632。 因此，我们排除了发射可能是回旋加速器同步辐射的可能性：推导出的高洛伦兹因子证明了来自这个前主序双星系统的90千兆赫发射的性质是同步辐射。 基于使用IRAM Plateau de Bure干涉仪进行的观测。 IRAM由INSU/CNRS（法国）、MPG（德国）和IGN（西班牙）支持。 显示英文摘要

摘要： The pre-main sequence binary system V773 Tau A shows remarkable flaring activity around periastron passage. Here, we present the observation of such a flare at a wavelength of 3 mm (90 GHz) performed with the Plateau de Bure Interferometer. We examine different possible causes for the energy losses responsible for the e-folding time of 2.3 hours of that flare. We exclude synchrotron, collisional, and inverse Compton losses because they are not consistent with observational constraints, and we propose that the fading of the emission is due to the leakage of electrons themselves at each reflection between the two mirror points of the magnetic structure partially trapping them. The magnetic structure compatible with both our leakage model and previous observations is that of a helmet streamer that, as in the solar case, can occur at the top of the X-ray-emitting, stellar-sized coronal loops of one of the stars. The streamer may extend up to 20 R and interact with the corona of the other star at periastron passage, causing recurring flares. The inferred magnetic field strength at the two mirror points of the helmet streamer is in the range 0.12 - 125 G, and the corresponding Lorentz factor, gamma, of the partially trapped electrons is in the range 20 < gamma < 632. We therefore rule out that the emission could be of gyro-synchrotron nature: the derived high Lorentz factor proves that the nature of the emission at 90 GHz from this pre-main binary system is synchrotron radiation. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).