论文标题
SDSS J143359.16+400636.0中的发光X射线瞬变：可能的潮汐破坏事件
A luminous X-ray transient in SDSS J143359.16+400636.0: a likely tidal disruption event
论文作者
论文摘要
我们介绍了一个发光X射线瞬态的发现，该瞬态在2月5日由Swift的X射线望远镜（XRT）检测到，位于Galaxy SDSS SDSS J143359.16+400636.0 AT Z = 0.099（Luminosity decance $ d $ D _} = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456 = 456.观察到瞬态是达到$ \ sim10^{44} $ erg s $^{ - 1} $的峰值光度，在0.3---10 kev X射线频带中，该频段是$ \ sim20 $ \ sim20 $ $倍，比峰值光学/UV亮度高。来自Zwicky瞬态设施（ZTF）和Swift的光学，UV和X射线灯曲面显示出与$ T^{ - 5/3} $一致的源的通量下降，并且与Nustar和Chandra的观察显示了柔软的X射线频谱，带有光子指数$γ= 2.9 \ pm0.1 $。 X射线/UV性能与众所周知的AGN特性不一致，并且与已知的X射线潮汐破坏事件（TDE）有更多共同点，这使我们得出结论，它可能是TDE。宽带光谱能量分布（SED）可以通过磁盘黑体模型很好地描述，内部磁盘温度为$ 7.3^{+0.3} _ { - 0.8} \ times10^{5} $ k，磁盘发射的大量（$> 40 $％）的磁盘发射中划分为X射线频带。 X射线检测后用Keck/LRIS拍摄的光谱揭示了宿主银河系中的衬里线比，这表明事件发生前的超质量黑孔，但没有看到TDE的宽线或其他指示。恒星速度分散剂意味着为活动提供动力的超级质量黑洞的质量是（$ m _ {\ rm bh} $/$/$ m _ {\ odot} $）$ = 7.41 \ pm0.41 $，我们估计该活动的Eddington Fraction fractions of Eddington fraction是$ 50％$ \ sim $ 50％。这种可能的TDE并未通过宽场光学调查或光学光谱法识别出来，表明没有宽场紫外线或X射线调查会错过更多此类事件。
We present the discovery of a luminous X-ray transient, serendipitously detected by Swift's X-ray Telescope (XRT) on 2020 February 5, located in the nucleus of the galaxy SDSS J143359.16+400636.0 at z=0.099 (luminosity distance $D_{\rm L}=456$ Mpc). The transient was observed to reach a peak luminosity of $\sim10^{44}$ erg s$^{-1}$ in the 0.3--10 keV X-ray band, which was $\sim20$ times more than the peak optical/UV luminosity. Optical, UV, and X-ray lightcurves from the Zwicky Transient Facility (ZTF) and Swift show a decline in flux from the source consistent with $t^{-5/3}$, and observations with NuSTAR and Chandra show a soft X-ray spectrum with photon index $Γ=2.9\pm0.1$. The X-ray/UV properties are inconsistent with well known AGN properties and have more in common with known X-ray tidal disruption events (TDE), leading us to conclude that it was likely a TDE. The broadband spectral energy distribution (SED) can be described well by a disk blackbody model with an inner disk temperature of $7.3^{+0.3}_{-0.8}\times10^{5}$ K, with a large fraction ($>40$%) of the disk emission up-scattered into the X-ray band. An optical spectrum taken with Keck/LRIS after the X-ray detection reveals LINER line ratios in the host galaxy, suggesting low-level accretion on to the supermassive black hole prior to the event, but no broad lines or other indications of a TDE were seen. The stellar velocity dispersion implies the mass of the supermassive black hole powering the event is log($M_{\rm BH}$/$M_{\odot}$)$=7.41\pm0.41$, and we estimate that at peak the Eddington fraction of this event was $\sim$50%. This likely TDE was not identified by wide-field optical surveys, nor optical spectroscopy, indicating that more events like this would be missed without wide-field UV or X-ray surveys.
