Evidence of a Tidal-disruption Event in GSN 069 from the Abnormal Carbon and Nitrogen Abundance Ratio
Evidence of a Tidal-disruption Event in GSN 069 from the Abnormal Carbon and Nitrogen Abundance Ratio
复制标题
DOI：
10.3847/2041-8213/ac2251
复制
发表时间：
2021-09
期刊：
影响因子：
--
通讯作者：
Zhenfeng Sheng;Ting-gui Wang;G. Ferland;X. Shu;Chenwei Yang;N. Jiang;Yang Chen
中科院分区：
文献类型：
--
作者：
Zhenfeng Sheng;Ting-gui Wang;G. Ferland;X. Shu;Chenwei Yang;N. Jiang;Yang Chen
GSN 069是一个超软x射线活动星系核，之前表现出巨大的x射线爆发和随后的长期衰变。它最近出现了x射线准周期性喷发（qpe）。我们报告在其远紫外光谱中检测到强氮谱线，但弱或不可检测的碳谱线。通过详细的光电离模型，我们使用C iv/N iv比值和氮谱线之间的其他比值来约束GSN 069的[C/N]丰度在−3.33到−1.91之间。我们认为，部分断裂的红巨星可以自然地解释紫外光谱中异常的C/N丰度，而围绕黑洞运行的幸存核心可能产生qpe。
GSN 069 is an ultra-soft X-ray active galactic nucleus that previously exhibited a huge X-ray outburst and a subsequent long-term decay. It has recently presented X-ray quasi-periodic eruptions (QPEs). We report the detection of strong nitrogen lines but weak or undetectable carbon lines in its far-ultraviolet spectrum. With a detailed photoionization model, we use the C iv/N iv] ratio and other ratios between nitrogen lines to constrain the [C/N] abundance of GSN 069 to be from −3.33 to −1.91. We argue that a partially disrupted red giant star can naturally explain the abnormal C/N abundance in the UV spectrum, while the surviving core orbiting the black hole might produce the QPEs.