论文标题
Cygnus的档案VLBA观察核无线电瞬变（CYG A-2）增强了潮汐破坏事件的解释
Archival VLBA observations of the Cygnus A Nuclear Radio Transient (Cyg A-2) Strengthen the Tidal Disruption Event Interpretation
论文作者
论文摘要
我们已经在2002年至2013年之间分析了Cygnus A的档案VLBA数据，以搜索\ citet {per18}在2015年发现的瞬态发射，约为0.4 \ arcsec〜cygnus a（cyg a-2）的核心。 \ citet {per18}使用VLA和VLBA档案数据（在1989年至1997年之间），以表明瞬态磁通密度的上升至少在不到20年的时间内提高了5倍。借助此处提供的其他数据，我们将上升时间修改为大约四年至六年，基于对源的新检测，从2011年10月起对15.4 GHz的新发现，我们的结果加强了CYG A-2的解释，这是潮汐破坏事件（TDE）的结果（TDE），因为我们可以确定对TDE的构造的位置，并且可以识别出构造型号的位置，并可以快速地播放正常播放的范围。 $ <0.9c $的扩展速度。尽管我们的结果与最近的X射线分析一致，但我们可以排除TDE时机的先前建议的日期。我们赞成在2009年初至2011年末之间的时机。应用\ citet {nak11}的模型，我们建议使用（密度依赖性的）总能量$> 10^{49} $ erg引起轻度相对论流出。由于我们的档案测量值的时间覆盖率得到改善，我们发现过去30年来CYG A-2以前一直处于高光度无线度状态。
We have analyzed archival VLBA data for Cygnus A between 2002 and 2013, to search for radio emission from the transient discovered in 2015 by \citet{per18} approximately 0.4\arcsec~ from the nucleus of Cygnus A (Cyg A-2). \citet{per18} use VLA and VLBA archival data (between 1989 and 1997) to show that the transient rises in flux density by a factor of at least five in less than approximately 20 years. With the additional data presented here, we revise the rise time to between approximately four years and six years, based on a new detection of the source at 15.4 GHz from October 2011. Our results strengthen the interpretation of Cyg A-2 as the result of a Tidal Disruption Event (TDE), as we can identify the location of the compact object responsible for the TDE and can estimate the angular expansion speed of the resulting radio emitting structures, equivalent to an apparent expansion speed of $<0.9c$. While our results are consistent with recent X-ray analyses, we can rule out a previously suggested date of early 2013 for the timing of the TDE. We favour a timing between early 2009 and late 2011. Applying the model of \citet{nak11}, we suggest a TDE causing a mildly relativistic outflow with a (density-dependent) total energy $>10^{49}$ erg. Due to the improved temporal coverage of our archival measurements, we find that it is unlikely that Cyg A-2 has previously been in a high luminosity radio state over the last 30 years.
