近日，武汉大学的王伟及其研究团队取得一项新进展。他们利用Fast观测了微类星体中的快速射电变化。相关研究成果已于2024年11月11日在国际知名学术期刊《中国物理快报》上发表。

在2020至2022年的FAST观测中，该研究团队首次报道了GRS 1915+105的亚秒级射电准周期振荡证据，这直接关联了准周期振荡与相对论性喷流的动力学。这些中心频率约为5赫兹的准周期振荡是瞬态的，并伴随着谱指数的强烈变化。

结合多波段观测数据，研究人员探讨了黑洞系统中可能产生射电准周期振荡的物理模型——喷流节的螺旋运动或喷流基部的进动。在不久的将来，基于FAST对微类星体进行的高时间分辨率射电监测，有望发现黑洞系统中更多新现象，这对于理解强引力环境下的物理过程至关重要。

据悉，微类星体是致密天体，通常包括吸积黑洞，这些黑洞能产生相对论性喷流。喷流的产生、准直和加速的物理机制尚不完全清楚。微类星体在多波段观测中展现出强烈的变异性。在X射线波段，这些源表现出快至毫秒时间尺度的快速变化特征，光变曲线中在约0.1赫兹至数十赫兹范围内存在显著的准周期振荡（QPO），然而QPO的物理起源仍不明确。作为最大的射电望远镜，FAST为研究微类星体中射电通量和极化的快速变化提供了契机。

附：英文原文

Title: Observations of Fast Radio Variations in Microquasars by FAST

Author:Wei Wang^*

Issue&Volume: 2024-11-11

Abstract: Microquasars are the compact objects generally including accreting black holes which produce relativistic jets. The physical mechanisms of jet launching, collimation, and acceleration are poorly understood. Microquasars show strong variability in multi-wavelength observations. In x-rays, the sources show the fast variation features down to millisecond time scales, with the prominent quasiperiodic oscillations (QPOs) around 0.1Hz–tens of Hz in light curves, however, physical origin of QPOs is still uncertain. FAST as the largest radio telescope provides the opportunity to study fast variability of both radio flux and polarization in microquasars. In the FAST observations from 2020–2022, we reported the first evidence of radio subsecond quasi-periodic oscillations of GRS 1915+105, providing the direct link between QPOs and the dynamics of relativistic jets. These QPOs with the centroid frequency around 5Hz are transient, accompanied with strong evolution of the spectral index. Combined with multiwavelength observations, we discuss the possible physical models to produce radio QPOs in BH systems: the helical motion of jet knots or precession of the jet base. In near future, high time resolution radio monitoring of microquasars based on FAST is expected to discover more new phenomena in black hole systems, which will be important for understanding the physics in strong gravity.

DOI: 10.1088/0256-307X/41/11/119701

Source: https://cpl.iphy.ac.cn/10.1088/0256-307X/41/11/119701