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arXiv 2401.12908astro-ph.HEastro-ph.GA
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来自潮汐瓦解事件 ASASSN-14li 的偶发性 X 射线外流

Episodic X-ray Outflows from the Tidal Disruption Event ASASSN-14li

Yukta Ajay, Dheeraj R. Pasham, Thomas Wevers, Eric R. Coughlin, Francesco Tombesi, Muryel Guolo, James F. Steiner

AI总结:

本文重新分析 ASASSN-14li 的 XMM-Newton 存档数据,发现其疑似超快外流的吸收特征在瓦解后约两年内间歇性消失与重现,并探讨相关盘与驱动机制。

摘要:

ASASSN-14li 是一个低红移(z=0.0206)潮汐瓦解事件(TDE),已在整个电磁波谱范围内得到广泛研究,并提供了迄今为止对 TDE 最灵敏的测量之一。其 X 射线谱较软且呈热态(kT~0.05 keV),并在 0.6–0.8 keV 之间显示出残余的类宽吸收特征;该特征可与蓝移的 O VII(静止系能量 0.57 keV)相联系,源于早期(光学发现后 40 天内)的超快外流(UFO)。通过仔细处理光子堆积效应并使用精确的 XSTAR 光致电离表模型,我们分析了来自 XMM-Newton 的全部存档 X 射线数据,并追踪该吸收特征在瓦解后约 4.5 年内的演化。我们的主要发现是:与以往文献相反,该吸收特征是短暂且间歇性的。假设 ASASSN-14li 中反复出现的吸收特征具有相同的物理基础(即外流),则可见外流在其演化最初约 2 年内多次消失并重新出现。此后未检测到可观测的光谱印记尽管理论研究表明外流是在爆发早期、超爱丁顿状态下启动的,但外流在瓦解后多年内表现出间歇性行为并不寻常。我们在内盘截断变化、辐射压以及磁驱动外流情景的背景下讨论了这种特殊行为。

英文摘要:

ASASSN-14li is a low-redshift ($z= 0.0206$) tidal disruption event (TDE) that has been studied extensively across the entire electromagnetic spectrum, and has provided one of the most sensitive measurements of a TDE to-date. Its X-ray spectrum is soft and thermal (kT$\sim$ 0.05 keV) and shows a residual broad absorption-like feature between 0.6-0.8 keV, which can be associated with a blue-shifted O VII (rest-frame energy 0.57 keV) resulting from an ultrafast outflow (UFO) at early times (within 40 days of optical discovery). By carefully accounting for pile-up and using precise XSTAR photo-ionization table models, we analyze the entire archival X-ray data from XMM-Newton and track the evolution of this absorption feature for $\sim$4.5 years post disruption. Our main finding is that, contrary to the previous literature, the absorption feature is transient and intermittent. Assuming the same underlying physical basis (i.e. outflows) for the recurring absorption feature in ASASSN-14li, the outflow is seen to disappear and reappear multiple times during the first $\sim$2 years of its evolution. No observable spectral imprint is detected thereafter. While theoretical studies suggest the launch of outflows in the early phases of the outburst during the super-Eddington regime, the outflow's intermittent behavior for multiple years after disruption is unusual. We discuss this peculiar behavior within the context of varying inner disk truncation, radiation pressure, and magnetically-driven outflow scenarios.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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