论文标题
部分可观测时空混沌系统的无模型预测
Dust Echoes from Luminous Fast Blue Optical Transients
论文作者
论文摘要
发光的快速蓝色光学瞬变（LFBOT），例如AT2018COW，形成了罕见的发动机动力爆炸，这些爆炸的起源不确定。这些事件的标志性特征是无线电/毫米同步加速器发射，该发射由快速（v> 0.1 c）弹出和密集的室内材料（CSM）的相互作用提供动力，该材料（CSM）延伸至祖先周围的大半径> 1E16 cm。假设该CSM是祖先的流出，我们表明在爆炸前几年的流出中，尘埃粒的大小可能会形成〜1微米。这种尘土飞扬的CSM会在峰值光之前衰减瞬态的紫外线（UV）发射，然后被亮度上升的亮度破坏，使最大最大的颜色变红（与LFBOT候选者的最大最大红色至蓝色颜色演变一致）。在被摧毁之前，灰尘的重新辐射会产生近红外（NIR）的亮度〜1E41-1E42 ERG/s持续几周，这是可以在瞬态迅速褪色的蓝色连续体上检测到的。我们表明，这种尘埃回声与AT2018COW中观察到的先前无法解释的NIR过量兼容。早期NIR光曲线的逐渐衰减可能是由CSM引起的，CSM集中在广角流出或圆环中，与AT2018COW的弹射器的高度非球形几何形状一致。 LFBOT的最大最大光学/紫外线和NIR随访提供了对其CSM环境的新探测，并在其祖细胞上放置了其他约束。
Luminous fast blue optical transients (LFBOTs) such as AT2018cow form a rare class of engine-powered explosions of uncertain origin. A hallmark feature of these events is radio/millimeter synchrotron emission powered by the interaction of fast (v > 0.1 c) ejecta and dense circumstellar material (CSM) extending to large radii > 1e16 cm surrounding the progenitor. Assuming this CSM to be an outflow from the progenitor, we show that dust grains up to ~1 micron in size can form in the outflow in the years before the explosion. This dusty CSM would attenuate the transient's ultraviolet (UV) emission prior to peak light, before being destroyed by the rising luminosity, reddening the pre-maximum colors (consistent with the pre-maximum red-to-blue color evolution of the LFBOT candidate MUSSES2020J). Re-radiation by the dust before being destroyed generates an near-infrared (NIR) "echo" of luminosity ~1e41-1e42 erg/s lasting weeks, which is detectable over the transient's rapidly fading blue continuum. We show that this dust echo is compatible with the previously unexplained NIR excess observed in AT2018cow. The gradual decay of the early NIR light curve can result from CSM which is concentrated in wide-angle outflow or torus, consistent with the highly aspherical geometry of AT2018cow's ejecta. Pre-maximum optical/UV and NIR follow-up of LFBOTs provide an new probe of their CSM environments and place additional constraints on their progenitors.
