At 66 Mpc, AT2019qiz is the closest optical tidal disruption event (TDE) to date, with a luminosity intermediate between the bulk of the population and the faint-and-fast event iPTF16fnl. Its proximity allowed a very early detection and triggering of multiwavelength and spectroscopic follow-up well before maximum light. The velocity dispersion of the host galaxy and fits to the TDE light curve indicate a black hole mass ≈10^6 M_⊙, disrupting a star of ≈1 M_⊙. By analysing our comprehensive UV, optical, and X-ray data, we show that the early optical emission is dominated by an outflow, with a luminosity evolution L ∝ t^2, consistent with a photosphere expanding at constant velocity (≳2000 km s^−1), and a line-forming region producing initially blueshifted H and He ii profiles with v = 3000–10 000 km s^−1. The fastest optical ejecta approach the velocity inferred from radio detections (modelled in a forthcoming companion paper from K. D. Alexander et al.), thus the same outflow may be responsible for both the fast optical rise and the radio emission – the first time this connection has been observed in a TDE. The light-curve rise begins 29 ± 2 d before maximum light, peaking when the photosphere reaches the radius where optical photons can escape. The photosphere then undergoes a sudden transition, first cooling at constant radius then contracting at constant temperature. At the same time, the blueshifts disappear from the spectrum and Bowen fluorescence lines (N iii) become prominent, implying a source of far-UV photons, while the X-ray light curve peaks at ≈10^41 erg s^−1. Assuming that these X-rays are from prompt accretion, the size and mass of the outflow are consistent with the reprocessing layer needed to explain the large optical to X-ray ratio in this and other optical TDEs, possibly favouring accretion-powered over collision-powered outflow models.

中文翻译：

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外流为附近快速发展的潮汐干扰事件 AT2019qiz 的光学上升提供动力

在 66 Mpc，AT2019qiz 是迄今为止最接近的光学潮汐破坏事件 (TDE)，其亮度介于大部分种群和微弱快速事件 iPTF16fnl 之间。它的接近性允许在最大光之前很早地检测和触发多波长和光谱跟踪。宿主星系的速度色散和 TDE 光曲线拟合表明黑洞质量 ≈10^6 M_⊙，扰乱了一颗 ≈1 M_⊙ 的恒星。通过分析我们综合的紫外线、光学和 X 射线数据，我们表明早期的光发射主要是外流，光度演化 L ∝ t^2，与以恒定速度（≳2000 km s ^−1)，以及产生初始蓝移的 H 和 He ii 剖面的线形成区域，其中 v = 3000–10 000 km s^−1。最快的光学喷射接近从无线电探测推断的速度（在 KD Alexander 等人即将发表的配套论文中建模），因此相同的流出可能是快速光学上升和无线电发射的原因——这种连接第一次出现在 TDE 中观察到。光曲线上升在最大光前 29 ± 2 天开始，当光球达到光子可以逃逸的半径时达到峰值。然后光球经历突然转变，首先以恒定半径冷却，然后在恒定温度下收缩。同时，蓝移从光谱中消失，鲍文荧光线 (N iii) 变得突出，这意味着远紫外光子的来源，而 X 射线光曲线在 ≈10^41 erg s^-1 处达到峰值。假设这些 X 射线来自快速吸积，