论文标题
SN 2004C的无线电分析揭示了不寻常的CSM密度曲线作为核心崩溃的预兆
Radio Analysis of SN 2004C Reveals an Unusual CSM Density Profile as a Harbinger of Core Collapse
论文作者
论文摘要
我们介绍了广泛的多频VLA和VLBA观察，对跨越$ \ sim（40-2793）$ DAME $ DAME $ DAME的无线电超级新闻（SN）IIB SN 2004C进行了探索。我们在同步器自我吸收（SSA）从爆炸的正向冲击中发射的背景下，我们解释了无线电光谱能分布（SED）的时间演变，因为它在先前由恒星祖细胞大众历史雕刻的室内介质（CSM）中扩展。 VLBA的观测和VLA数据的建模指向一个平均速度$ \ sim0.06c $的blastwave，其能量为$ \ sim 10^{49} $ erg。我们的建模进一步揭示了平坦的CSM密度曲线$ρ_ {\ rm {csm}}} \ propto r^{ - 0.03 \ pm0.22} $ to tow tow tow tow to a Break rak radius $ r_ {br} $ρ_ {\ rm {csm}}} \ propto r^{ - 2.3 \ pm 0.5} $在较大的radii处。我们推断，密度曲线的平坦部分对应于具有质量$ $ \ sim0.021 m _ {\ odot} $的CSM外壳，并且祖细胞的有效质量损失速率随时间在$（50-500）\ times 10^{-5} m _ {\ odot} \ odot} m _ {\ odot} $ rmm rmm rmm rmm {y rm rmm = rm rm c {y rm} { $ v_w = 1000 $ km $ s^{ - 1} $和冲击微物理参数$ε_e= 0.1，ε_b= 0.01 $。这些结果增加了与传统的几个世纪发展，导致核心崩溃的几个世纪发展的传统单风质量损失场景的越来越多的观察证据。潜在的可行场景包括由重力波动支持的质量损失和/或与二进制伴侣的相互作用。
We present extensive multi-frequency VLA and VLBA observations of the radio-bright supernova (SN) IIb SN 2004C that span $\sim(40-2793)$ days post-explosion. We interpret the temporal evolution of the radio spectral energy distribution (SED) in the context of synchrotron self-absorbed (SSA) emission from the explosion's forward shock as it expands in the circumstellar medium (CSM) previously sculpted by the mass-loss history of the stellar progenitor. VLBA observations and modeling of the VLA data point to a blastwave with average velocity $\sim0.06c$ that carries an energy of $\sim 10^{49}$ erg. Our modeling further reveals a flat CSM density profile $ρ_{\rm{CSM}} \propto R^{-0.03 \pm0.22}$ up to a break radius $R_{br} \approx (1.96 \pm 0.10) \times 10^{16}$ cm, with a steep density gradient following $ρ_{\rm{CSM}} \propto R^{-2.3 \pm 0.5}$ at larger radii. We infer that the flat part of the density profile corresponds to a CSM shell with mass $\sim0.021 M_{\odot}$, and that the progenitor's effective mass-loss rate varied with time over the range $(50-500) \times 10^{-5} M_{\odot} \rm{yr}^{-1}$ for an adopted wind velocity $v_w =1000$ km $s^{-1}$ and shock microphysical parameters $ε_e = 0.1, ε_B = 0.01$. These results add to the mounting observational evidence for departures from the traditional single-wind mass-loss scenarios in evolved, massive stars in the centuries leading up to core collapse. Potentially viable scenarios include mass loss powered by gravity waves and/or interaction with a binary companion.
