An X-ray view of the ambiguous nuclear transient AT2019pev
An X-ray view of the ambiguous nuclear transient AT2019pev
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模糊核瞬变 AT2019pev 的 X 射线视图
DOI：
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发表时间：
2022
影响因子：
4.8
通讯作者：
T. Holoien
中科院分区：
文献类型：
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作者：
Zhefu Yu;C. Kochanek;S. Mathur;K. Auchettl;D. Grupe;T. Holoien
AT2019pev是位于z = 0.096的窄线塞弗特1星系中的核瞬变。存档的紫外、光学和红外数据显示了潮汐破坏事件（TDEs）和活动星系核（agn）的特征，其性质尚不完全清楚。我们展示了自第一个Swift XRT时代以来，由Swift、钱德拉和NICER在173天内对AT2019pev的演化进行的详细x射线观测。从第一个Swift XRT纪元到光曲线峰值，x射线的光度在五天内增加了五倍。光曲线在约75天内衰减10倍，然后在晚些时候变平，有微弱的再亮趋势。x射线谱在峰前呈“越亮越硬”的趋势，峰后呈“越暗越硬”的趋势，这可能表明吸积状态发生了转变。存档的地面光学观测显示了与x射线光曲线相似的时间演化。超越地面观测的季节限制，盖亚光曲线在光学发现223天后上升到一个同样明亮或更亮的峰值。结合我们的x射线分析和存档的多波长数据，AT2019pev更像AGN瞬态。
AT2019pev is a nuclear transient in a narrow-line Seyfert 1 galaxy at z = 0.096. The archival ultraviolet, optical and infrared data showed features of both tidal disruption events (TDEs) and active galactic nuclei (AGNs), and its nature is not fully understood. We present detailed X-ray observations of AT2019pev taken with Swift, Chandra and NICER over 173 days of its evolution since the first Swift XRT epoch. The X-ray luminosity increases by a factor of five in five days from the first Swift XRT epoch to the lightcurve peak. The lightcurve decays by a factor of ten over ∼75 days and then flattens with a weak re-brightening trend at late times. The X-ray spectra show a ‘harder-when-brighter’ trend before peak and a ‘harder-when-fainter’ trend after peak, which may indicate a transition of accretion states. The archival ground-based optical observations show similar time evolution as the X-ray lightcurves. Beyond the seasonal limit of the ground-based observations, the Gaia lightcurve is rising toward an equally bright or brighter peak 223 days after the optical discovery. Combining our X-ray analysis and archival multi-wavelength data, AT2019pev more closely resembles an AGN transient.