论文标题
coalescence SMBHB候选SDSS的VLBI成像J143016.05+230344.4
VLBI imaging of the pre-coalescence SMBHB candidate SDSS J143016.05+230344.4
论文作者
论文摘要
语境。最近，据报道，SDSS J143016.05+230344.4（J1430+2303）在最后的合并阶段是超级质量的黑洞二元（SMBHB）。这可能是人类历史上可以观察到的第一次SMBHB结合事件。合并之前和之后的J1430+2303的无线电观察结果将对SMBHB的能量和环境提供独特的诊断。 目标。我们探索了与当前的X射线和光学活动密切相关的银河核区域的无线电发射，并有助于在聚结之前了解黑洞积聚和流出的状态。 方法。非常长的基线干涉法（VLBI）成像是唯一提供毫秒级高分辨率的方法，可以在银河尺度上排除扩散发射的污染。我们观察到J1430+2303的欧洲VLBI网络为1.7 GHz，而2022年2月下旬和3月初的基线阵列为1.6和4.9 GHz。 结果。在所有三个VLBI图像中都检测到一个紧凑的组件。它的亮度温度> 10^8 k，尺寸<0.8 pc的未解决形态和平坦的无线电频谱。这些观察性特征与大型开头流出或风不一致，但表明这种紧凑的组件可能是喷气机或电晕。 VLBI近60％的发射解决了，可能来自以前无线电活动的残余裂片，结构化射流的外层或狭窄线区域的碟中风形成的冲击。 结论。当前的VLBI图像尚未显示无线电爆发的迹象。我们的观察结果提供了钙化前无线电数据，这是与合并后未来比较研究的重要参考。特别是，进一步解决喷气机将为探测与灵感的二进制黑洞相关的动力特征铺平道路。
Context. Recently, SDSS J143016.05+230344.4 (J1430+2303) was reported to be a supermassive black hole binary (SMBHB) in the final coalescence phase. It is probably the first SMBHB coalescence event observable in human history. Radio observations of J1430+2303 before and after coalescence will provide a unique diagnosis of the energetics and environment of the SMBHB. Aims. We explore the radio emission from the galactic nucleus region that is closely related to the current X-ray and optical activities and helps to understand the state of black hole accretion and outflow before coalescence. Methods. Very long baseline interferometry (VLBI) imaging is the only method that offers milli-arcsecond-level high resolution that can exclude the contamination by diffuse emission on galactic scales. We observed J1430+2303 with the European VLBI Network at 1.7 GHz and with the Very Long Baseline Array at 1.6 and 4.9 GHz in late February and early March 2022. Results. A compact component is detected in all three VLBI images. It has a brightness temperature of > 10^8 K, an unresolved morphology with a size < 0.8 pc, and a flat radio spectrum. These observational features are inconsistent with large opening-angle outflows or winds, but indicate that this compact component might be a jet or a corona. Nearly 60% of the emission is resolved by VLBI and may come from remnant lobes of previous radio activities, the outer layers of a structured jet, or shocks formed by the disc winds in the narrow line region. Conclusions. Current VLBI images do not yet show signs of radio outbursts. Our observations provide pre-coalescence radio data that are an important reference for future comparative studies with the post-merger. In particular, further resolving the jet will pave the way for probing the dynamical features associated with inspiralling binary black holes.
