论文标题
附近的超级矮人二进制的无线电排放：一项多频研究
Radio emission in a nearby ultracool dwarf binary: a multi-frequency study
论文作者
论文摘要
替代三重系统VHS J125601.92 $ - $ 125723.9由相等的质量M7.5棕色矮人二进制和L7低质量替代物体组成。在这项工作中，我们旨在确定VHS 1256 $ - $ 1257中的无线电排放的起源，同时讨论Ultracool Dwarfs（UCDS）无线电排放所涉及的预期机制。我们使用Karl G. Jansky非常大的阵列，非常漫长的基线干涉量（VLBI）网络，增强的多元元素近距离链接的干涉仪网络，北部扩展毫米阵列以及Atacama大毫米阵列从5 GHZ到达5 GHz的频率到2010年，2010年的频率从5 GHZ到2017年，北部大毫米阵列在2017年播放了2017年，我们在2010年播放了2017年，我们在5 GHZ的频率上观察到了这个系统。在6 GHz和33 GHz的同时，与VHS中央二进制的预期位置约1256美元 - $ 1257。检测到的Stokes I密度通量分别为73 $ \ pm $ 4 $μ$ JY和83 $ \ pm $ 13 $ $ $ JY，没有可检测到的圆形极化或脉冲。使用VLBI阵列在较高的频率（230 GHz和345 GHz）或5 GHz时未检测到发射。在6 GHz的近3年中，排放似乎是稳定的。为了解释从检测和非检测中获得的约束，我们考虑了多种情况，包括热和非热发射，以及二进制每个组成部分的不同贡献。我们的结果可以很好地解释，非热陀螺仪排放发射起源于辐射带，其血浆密度较低（n $ _e $ = 300 $ = 300 $ - $ 700 cm $^{ - 3} $），中等磁场强度（B $ \ $ 140 g），$ 140 g），以及$ d n / d n / d n / d n / d n / d n / d； $δ$固定为1.36。这些辐射带需要在两个组件中都存在，并且还需要赤道观察。
The substellar triple system VHS J125601.92$-$125723.9 is composed by an equal-mass M7.5 brown dwarf binary and a L7 low-mass substellar object. In this work, we aim to identify the origin of the radio emission occurring in the central binary of VHS 1256$-$1257 while discussing the expected mechanisms involved in the radio emission of ultracool dwarfs (UCDs). We observed this system with the Karl G. Jansky Very Large Array, the European very-long-baseline interferometry (VLBI) Network, the enhanced Multi Element Remotely Linked Interferometer Network, the NOrthern Extended Millimeter Array, and the Atacama Large Millimetre Array at frequencies ranging from 5 GHz up to 345 GHz in several epochs during 2017, 2018, and 2019. We have found radio emission at 6 GHz and 33 GHz coincident with the expected position of the central binary of VHS~1256$-$1257. The Stokes I density flux detected were 73 $\pm$ 4 $μ$Jy and 83 $\pm$ 13 $μ$Jy, respectively, with no detectable circular polarisation or pulses. No emission is detected at higher frequencies (230 GHz and 345 GHz) nor at 5 GHz with VLBI arrays. The emission appears to be stable over almost 3 years at 6 GHz. To explain the constraints obtained both from the detections and non-detections we considered multiple scenarios including thermal and non-thermal emission, and different contributions from each component of the binary. Our results can be well explained by non-thermal gyrosynchrotron emission originating at radiation belts with a low plasma density (n$_e$ = 300$-$700 cm$^{-3}$), a moderate magnetic field strength (B $\approx$ 140 G), and an energy distribution of electrons following a power-law ($d N / d E \propto E^{- δ}$) with $δ$ fixed at 1.36. These radiation belts would need to be present in both components and also be viewed equatorially.
