Detection of Linearly Polarized 6.9 mm Continuum Emission from the Class 0 Young Stellar Object NGC1333 IRAS4A

Nonlinear reflection process of linearly-polarized, broadband Alfvén waves in the fast solar wind

Using one-dimensional numerical simulations, we study the elementary process of Alfvén wave reflection in a uniform medium, including nonlinear effects. In the linear regime, Alfvén wave reflection is triggered only by the inhomogeneity of the medium, whereas in the nonlinear regime, it can occur via nonlinear wave-wave interactions. Such nonlinear reflection (backscattering) is typified by decay instability. In most studies of decay instabilities, the initial condition has been a circularly polarized Alfvén wave. In this study we consider a linearly polarized Alfvén wave, which drives density…

Discovery of a complex linearly polarized spectrum of Betelgeuse dominated by depolarization of the continuum

Betelgeuse is an M supergiant that harbors spots and giant granules at its surface and presents linear polarization of its continuum. We have previously discovered linear polarization signatures associated with individual lines in the spectra of cool and evolved stars. Here, we investigate whether a similar linearly polarized spectrum exists for Betelgeuse. We used the spectropolarimeter Narval, combining multiple polarimetric sequences to obtain high signal-to-noise ratio spectra of individual lines, as well as the least-squares deconvolution (LSD) approach. We have discovered the existence o…

MeerKAT上的千脉冲星阵列项目XIV：论高线性偏振脉冲星信号

The Thousand-Pulsar-Array programme on MeerKAT XIV: On the high linearly polarized pulsar signals

本文在TPA的249颗亮脉冲星上验证仅用线偏振度大于80%采样拟合RVM的方法，将失败率由59%降至5%，支持相干曲率辐射机制。

Discovery of the subsecond linearly polarized spikes of synchrotron origin in the UV Ceti giant optical flare

During our optical monitoring of UV Ceti, iconic late-type flaring star, with high temporal resolution using the Russian 6-m telescope in 2008 we detected a giant flare with the amplitude of about 3 magnitudes in $U$-band. Near flare maximum more than a dozen of spike bursts have been discovered with triangular shapes and durations from 0.6 to 1.2 s and maximal luminosities in the range $(1.5-8)\times10^{27}$ erg~s$^{-1}$. For the half of these events the linear polarization exceeds 35% with significance better than $5σ$. We argue that these events are synchrotron emission of electron streams …

Minor ion heating in spectra of linearly and circularly polarized Alfvén waves: Thermal and non-thermal motions associated with perpendicular heating

Minor ion (such as $He^{2+}$) heating via nonresonant interaction with spectra of linearly and circularly polarized Alfvén waves (LPAWs and CPAWs hereafter) is studied. The obtained analytic solutions are in good agreement with the simulation results, indicating that newborn ions are heated by low-frequency Alfvén waves with finite amplitude in low-beta plasmas such as the solar corona. The analytic solutions also reproduce the preferential heating of heavy ions in the solar wind. In the presence of parallel propagating Alfvén waves, turbulence-induced particle motion is clearly observed in th…