Title: Radiative-transfer models for dusty Type II supernovae Show Chinese title

Title: 尘埃丰富的II型超新星的辐射转移模型

Abstract: Dust is expected to form on a year timescale in core-collapse supernova (SN) ejecta. Its existence is revealed through an infrared brightening, an optical dimming, or a blue-red emission-line profile asymmetry. To investigate how the dust location and amount impact observations, we computed ultraviolet-to-optical spectra of interacting and standard, noninteracting Type II SNe using state-of-the-art models -- for simplicity we adopted 0.1micron silicate grains. These models account for the full ejecta and treat both radioactive decay and shock power that arises from interaction of the ejecta with circumstellar material. In a Type IIn SN such as 1998S at one year, approximately 3e-4Msun of dust within the dense shell reproduces the broad, asymmetric Halpha profile. It causes an optical dimming of ~2mag (which obscures any emission from the inner, metal-rich ejecta) but, paradoxically, a more modest dimming of the ultraviolet, which originates from the outer parts of the dense shell. In Type II SNe with late-time interaction, such as SN2017eaw, dust in the low-mass, fast outer ejecta dense shell tends to be optically thin, impacting little the optical spectrum for dust masses of order 1e-4Msun. In such SNe II with interaction, dust in the inner metal-rich ejecta has negligible effect on observed spectra in the ultraviolet and optical. In noninteracting SNe II, dust within the metal-rich ejecta preferentially quenches the [OI]6300,6364 and [CaII]7291,7323 metal lines, biasing the emission in favor of the H-rich material which generates the Halpha and FeII emission below 5500A. Our model with 5e-4Msun of dust below 2000km/s matches closely the optical spectrum of SN1987A at 714d. Modeling historical SNe requires treating both the ejecta material and the dust, as well as multiple power sources, although interaction power will generally dominate. Show Chinese abstract

Abstract: 在核心坍缩超新星（SN）喷出物中，尘埃预计在一年的时间尺度上形成。它的存在通过红外变亮、光学变暗或蓝红发射线轮廓不对称性被揭示出来。为了研究尘埃的位置和数量如何影响观测结果，我们使用最先进的模型计算了相互作用和标准非相互作用II型超新星的紫外至光学光谱——为简单起见，我们采用了0.1微米硅酸盐颗粒。这些模型考虑了完整的喷出物，并处理了放射性衰变和由于喷出物与周围介质相互作用产生的冲击功率。在像1998S这样的IIn型超新星中，一年后密集壳层中的约3e-4Msun尘埃可以再现宽广的不对称Halpha轮廓。它会导致约2mag的光学变暗（掩盖了来自内部富金属喷出物的任何发射），但矛盾的是，紫外波段的变暗程度较小，紫外波段来自密集壳层的外部区域。在晚期相互作用的II型超新星，如SN2017eaw中，低质量、快速外喷出物密集壳层中的尘埃通常光学薄，对于尘埃质量约为1e-4Msun的情况，对光学光谱影响很小。在具有相互作用的此类II型超新星中，内部富金属喷出物中的尘埃对紫外和光学波段的观测光谱几乎没有影响。在非相互作用的II型超新星中，富金属喷出物中的尘埃优先抑制[OI]6300,6364和[CaII]7291,7323金属线，使发射偏向于产生Halpha和5500A以下FeII发射的H-rich物质。我们模型中低于2000km/s的5e-4Msun尘埃与SN1987A在714d时的光学光谱非常吻合。建模历史超新星需要同时处理喷出物物质和尘埃，以及多个能量来源，尽管相互作用能量通常占主导地位。