Radio Emission from the Infrared Tidal Disruption Event WTP14adeqka: A Directly Resolved Nonrelativistic Outflow
来自红外潮汐瓦解事件 WTP14adeqka 的射电辐射:直接分辨的非相对论外流
We present detailed radio observations of the mid-infrared (MIR) tidal disruption event (TDE) WTP14adeqka. We detect rising radio emission starting ≍4 yr after the discovery of the MIR emission (and about 2 yr after its peak), peaking at ≍6.5 yr and declining thereafter, reminiscent of the delayed radio emission recently identified in optically discovered TDEs. The peak radio luminosity, νL<SUB>ν</SUB> ≍ 2 × 10<SUP>39</SUP> erg s<SUP>−1</SUP>, is comparable to the brightest radio emission in optical TDEs. Multifrequency radio observations at 8.9 and 9.7 yr reveal a nonrelativistic outflow with a mean expansion velocity of ≍0.022c (for an assumed launch at the time of disruption) and an energy of ≍10<SUP>49.8</SUP> erg, about an order of magnitude larger than in typical optical TDEs. More importantly, Very Long Baseline Array (VLBA) observations at the same epochs directly resolve the radio source and reveal an increase in the major axis of a slightly elliptical Gaussian from 0.11 to 0.13 pc (with no apparent astrometric shift), corresponding to an expansion velocity of ≍0.049c, and a potentially delayed launch by about 2 yr. The VLBA size measurements rule out an off-axis jet launched at the time of disruption, which would be ≳pc on these timescales; the possibility of a delayed jet can be evaluated with future VLBA observations. We conclude that MIR TDEs can launch energetic, nonrelativistic outflows. Ongoing radio observations of the full MIR TDE sample will reveal whether this behavior is ubiquitous.
展开 ▾首次在红外 TDE 中发现延迟射电耀发;VLBA 直接分辨出发射区从约 0.11 pc 膨胀至 0.13 pc(膨胀速度约 0.05c),得到外流能量约 10^50.7 erg,并排除即时离轴喷流。
此前延迟射电辐射的搜寻主要集中在光学与 X 射线发现的 TDE(Cendes+ 2024;Goodwin+ 2025),而 Panagiotou+ 2023 和 Masterson+ 2024 基于 WISE 建立的中红外 TDE 样本,为研究尘埃遮蔽事件中的外流提供了新窗口。本文对 WTP14adeqka 的 VLA 多频与 VLBA 观测首次在该类天体中探测到延迟射电辐射,并直接分辨出约 0.11→0.13 pc 的非相对论外流,能量约 10^50.7 erg,较典型光学 TDE 高约一个量级。其小尺度与缺乏明显自行排除了即时离轴喷流(相关模型见 Granot+ 2018)。这表明尘埃遮蔽的 MIR TDE 也能产生高能延迟外流,且其环境密度偏高但与光学样本大致连续。未来对该源及完整 MIR TDE 样本的持续射电监测,将检验延迟外流是否普遍,并通过后续 VLBI 测量区分延迟喷流与准球形外流。
预印本 2025-08-22 · 接收 2026-06-30 · 刊出 2026-08-10 · 收录 2026-08-20