...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>PASJ: Publications of the Astronomical Society of Japan >Multi-epoch VERA observations of sagittarius A*. I. images and structural variability
【24h】

Multi-epoch VERA observations of sagittarius A*. I. images and structural variability

机译：人马座A *的多时期VERA观测。一，图像和结构变异性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We report on the results of multi-epoch observations of Sgr A* with VLBI Exploration of Radio Astrometry (VERA) at 43 GHz, carried out from 2004 to 2008. We detected a time variation of the flux at the 11% level and the intrinsic size at 19%. In addition, comparisons with previous Very Long Baseline Array (VLBA) results showed that Sgr A* underwent a flaring event for at least longer than 10 d in 2007 May. The intrinsic size of Sgr A* remained unchanged within the 1 level from the size before/after the flaring event, indicating that the brightness temperature of Sgr A* was increased. The flaring event occurred within 31 d, which is shorter than the refractive time scale. Moreover it is difficult to explain the increase in the spectral index at the flaring event by a simple interstellar scattering model. Hence, the flaring event is most likely associated with changes in the intrinsic properties of Sgr A*. We considered the origin of the brightness temperature variation, and concluded that the flaring event of Sgr A* could be explained by the continuous heating of electrons, such as a standing shock in accretion flow.
机译：我们报告了从2004年至2008年在43 GHz上进行的VLBI射电占星术（VERA）多阶段观测Sgr A *的结果。我们检测到了11％的通量和本征的时间变化大小为19％。此外，与以前的甚长基线阵列（VLBA）结果进行的比较表明，Sgr A *在2007年5月经历了至少10天以上的爆发事件。从燃烧事件之前/之后的尺寸来看，Sgr A *的固有尺寸在1级范围内保持不变，表明Sgr A *的亮度温度增加了。爆发事件发生在31 d内，比折射时间标度短。此外，很难通过简单的星际散射模型来解释在耀斑事件中光谱指数的增加。因此，扩口事件很可能与Sgr A *的内在特性发生变化有关。我们考虑了亮度温度变化的起因，并得出结论，Sgr A *的爆发事件可以用电子的持续加热来解释，例如吸积流中的静压冲击。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号