Tracing the hot spot motion using the next generation Event Horizon Telescope (ngEHT)

分类： 天文学 >> 天文学 提交时间： 2023-02-19

Razieh Emami Paul Tiede Sheperd S. Doeleman Freek Roelofs Maciek Wielgus Lindy Blackburn Matthew Liska Koushik Chatterjee Bart Ripperda Antonio Fuentes Avery Broderick Lars Hernquist Charles Alcock Ramesh Narayan Randall Smith Grant Tremblay Angelo Ricarte He Sun Richard Anantua Yuri Y. Kovalev

摘要： We propose to trace the dynamical motion of a shearing hot spot near the SgrA* source through a dynamical image reconstruction algorithm, StarWarps. Such a hot spot may form as the exhaust of magnetic reconnection in a current sheet near the black hole horizon. A hot spot that is ejected from the current sheet into an orbit in the accretion disk may shear and diffuse due to instabilities at its boundary during its orbit, resulting in a distinct signature. We subdivide the motion to two distinct phases; the first phase refers to the appearance of the hot spot modelled as a bright blob, followed by a subsequent shearing phase simulated as a stretched ellipse. We employ different observational arrays, including EHT(2017,2022) and the next generation event horizon telescope (ngEHTp1, ngEHT) arrays, in which few new additional sites are added to the observational array. We make dynamical image reconstructions for each of these arrays. Subsequently, we infer the hot spot phase in the first phase followed by the axes ratio and the ellipse area in the second phase. We focus on the direct observability of the orbiting hot spot in the sub-mm wavelength. Our analysis demonstrates that newly added dishes may easily trace the first phase as well as part of the second phase, before the flux is reduced substantially. The algorithm used in this work can be extended to any other types of the dynamical motion. Consequently, we conclude that the ngEHT is a key to directly observe the dynamical motions near variable sources, such as SgrA*.

同行评议状态:待评议

 点击量 15  下载量 12  评论