The Broad Absorption Line Tidal Disruption Event iPTF15af: Optical and Ultraviolet Evolution
The Broad Absorption Line Tidal Disruption Event iPTF15af: Optical and Ultraviolet Evolution
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DOI：
10.3847/1538-4357/ab04b0
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发表时间：
2018-09
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通讯作者：
N. Blagorodnova;S. Cenko;S. Kulkarni;I. Arcavi;J. Bloom;G. Duggan;A. Filippenko;C. Fremling;A. Horesh;G. Hosseinzadeh;E. Karamehmetoglu;A. Levan;F. Masci;P. Nugent;D. Pasham;S. Veilleux;R. Walters;L. Yan;W. Zheng
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作者：
N. Blagorodnova;S. Cenko;S. Kulkarni;I. Arcavi;J. Bloom;G. Duggan;A. Filippenko;C. Fremling;A. Horesh;G. Hosseinzadeh;E. Karamehmetoglu;A. Levan;F. Masci;P. Nugent;D. Pasham;S. Veilleux;R. Walters;L. Yan;W. Zheng
我们提出了多波长观测的潮汐中断事件（TDE）iPTF 15 af，发现在红移z = 0.07897的中间帕洛玛瞬态工厂调查。瞬态的光学和紫外（UV）光变曲线显示出超过5个月的缓慢衰减，与以前的光学发现的TDE一致。它也有一个相当的黑体峰值亮度。由光学和紫外数据推断的温度值为（3-5）× 104 K。在发现后的前5个月内，在X射线中未检测到瞬变。光谱在He ii区显示出两条明显的宽发射线，在稍后的时间也有Hα发射。此外，检测到来自[N iii]和[O iii]的发射，可能由Bowen荧光效应产生。紫外光谱显示出与N v、C iv、Si iv和可能的P v的高电离态相关的宽发射和吸收线，这些特征类似于宽吸收线类星体（BAL类星体），需要柱密度为cm−2的吸收体。这种光学上厚的气体也可以解释软X射线中无法检测到的原因。在最大速度下，具有最高柱密度物质的吸收线的轮廓与BAL类星体相反。我们认为，在早期的TDE耀斑产生的辐射压力可能提供了这种气体的初始加速机制。对未来TDE的紫外线光谱监测可以检验这一建议。
We present multiwavelength observations of the tidal disruption event (TDE) iPTF15af, discovered by the intermediate Palomar Transient Factory survey at redshift z = 0.07897. The optical and ultraviolet (UV) light curves of the transient show a slow decay over 5 months, in agreement with previous optically discovered TDEs. It also has a comparable blackbody peak luminosity of . The inferred temperature from the optical and UV data shows a value of (3–5) × 104 K. The transient is not detected in X-rays up to within the first 5 months after discovery. The optical spectra exhibit two distinct broad emission lines in the He ii region, and at later times also Hα emission. Additionally, emission from [N iii] and [O iii] is detected, likely produced by the Bowen fluorescence effect. UV spectra reveal broad emission and absorption lines associated with high-ionization states of N v, C iv, Si iv, and possibly P v. These features, analogous to those of broad absorption line quasars (BAL QSOs), require an absorber with column densities cm−2. This optically thick gas would also explain the nondetection in soft X-rays. The profile of the absorption lines with the highest column density material at the largest velocity is opposite that of BAL QSOs. We suggest that radiation pressure generated by the TDE flare at early times could have provided the initial acceleration mechanism for this gas. Spectral UV line monitoring of future TDEs could test this proposal.