Early observations of the nearby type Ia supernova SN 2015F
R. Cartier, M. Sullivan, R. Firth, G. Pignata, P. Mazzali, K. Maguire, M. J. Childress, I. Arcavi, C. Ashall, B. Bassett, S. M. Crawford, C. Frohmaier, L. Galba… 展开作者
R. Cartier, M. Sullivan, R. Firth, G. Pignata, P. Mazzali, K. Maguire, M. J. Childress, I. Arcavi, C. Ashall, B. Bassett, S. M. Crawford, C. Frohmaier, L. Galbany, A. Gal-Yam, G. Hosseinzadeh, D. A. Howell, C. Inserra, J. Johansson, E. K. Kasai, C. McCully, S. Prajs, S. Prentice, S. Schulze, S. J. Smartt, K. W. Smith, M. Smith, S. Valenti, D. R. Young
We present photometry and time-series spectroscopy of the nearby type Ia supernova (SN Ia) SN 2015F over $-16$ days to $+80$ days relative to maximum light, obtained as part of the Public ESO Spectroscopic Survey of Transient Objects (PESSTO). SN 2015F is a slightly sub-luminous SN Ia with a decline rate of $Δm15(B)=1.35 \pm 0.03$ mag, placing it in the region between normal and SN 1991bg-like events. Our densely-sampled photometric data place tight constraints on the epoch of first light and form of the early-time light curve. The spectra exhibit photospheric C II $λ6580$ absorption until $-4$ days, and high-velocity Ca II is particularly strong at $<-10$ days at expansion velocities of $\simeq$23000\kms. At early times, our spectral modelling with syn++ shows strong evidence for iron-peak elements (Fe II, Cr II, Ti II, and V II) expanding at velocities $>14000$ km s$^{-1}$, suggesting mixing in the outermost layers of the SN ejecta. Although unusual in SN Ia spectra, including V II in the modelling significantly improves the spectral fits. Intriguingly, we detect an absorption feature at $\sim$6800 Å that persists until maximum light. Our favoured explanation for this line is photospheric Al II, which has never been claimed before in SNe Ia, although detached high-velocity C II material could also be responsible. In both cases the absorbing material seems to be confined to a relatively narrow region in velocity space. The nucleosynthesis of detectable amounts of Al II would argue against a low-metallicity white dwarf progenitor. We also show that this 6800 Å feature is weakly present in other normal SN Ia events, and common in the SN 1991bg-like sub-class.
Nearby Supernova Rates from the Lick Observatory Supernova Search. II. The Observed Luminosity Functions and Fractions of Supernovae in a Complete Sample
Precursors of Supernovae from Mass Eruption: Prospects for Early Warning of Nearby Core-collapse Supernovae
最近对大部分II型超新星的观测显示，在非常接近原始恒星的地方有致密的星周介质（CSM）的痕迹。如果这个CSM是在核心坍缩前几个月由爆发性质量损失产生的，那么爆发本身可能是一个前兆，有助于作为不久的将来超新星的早期预警。利用基于开放源代码CHIPS的辐射流体动力学模拟，我们从理论上模拟了一颗红超巨星的质量爆发辐射。我们发现，对于中等质量的爆发，光度通常在$10^{39}$ erg s $^{-1}$的数量级上，可以持续数百天，直到恒星爆炸，并且主要在红外线（峰值附近从-9到-11等）明亮。我们讨论的观测策略，找到这些签名从银河系和本地II型超新星。
Interaction of hemispherical blast waves with inhomogeneous spheres: Probing the collision of a supernova ejecta with a nearby companion star in the laboratory
No evidence for an early seventeenth-century Indian sighting of Keplers supernova (SN1604)
在最近的一篇论文中，Sule et al.（Astronomical Notes，vol. 332（2011），655）认为，17世纪早期印度的一幅带有龙头尾巴的人马座壁画表明，印度天文学家也看到了1604年的明亮超新星。在本文中，它将表明，这种识别是基于传统的伊斯兰占星术图像的误解，并声称壁画代表了17世纪早期的印度目击超新星的1604年必须被拒绝。
WFST Supernovae in the First Year: I. Statistical Study of 16 Early-phase Type Ia Supernovae from the Pilot Survey
University of Science and Technology of China（中国科学技术大学）；National Astronomical Observatory of Japan（日本国立天文台）；Kyoto University（京都大学）；University of Turku（图尔库大学）
Optical Observations of the Nearby Type Ia Supernova 2021hpr
本文介绍了对附近Ia型超新星（SN）2021 hpr的光学光度和光谱观测。观测涵盖了相对于$B$波段最大亮度的$-$ 14.37至+63.68天的相位。SN 2021 hpr的多波段光/色曲线演化与正常Ia型超新星（SNe Ia）相似，但有一些相位不同，特别是在峰值亮度之前的$V-R$色曲线上出现了一个平台相位，这与SN 2017 cbv相似。我们在t $\sim -$ 14.4天观测到的第一个光谱显示，Si II $λ$ 6355特征（$\sim$ 21，000 km s $^{-1}$）的速度高于同一相位的其他正常速度（NV）SNe Ia。根据$\sim$ 12，420 km s $^{-1}$的Si II $λ$ 6355在最大光附近的速度，我们推断SN 2021 hpr是一个介于高速（HV）和NV SNe Ia之间的过渡天体。与此同时，Si II $λ$ 6355特征显示出约800 km s $^{-1}$ day $^{-1}$的高速度梯度（HVG），相对于$B$带最大值，从大约$-$ 14.37天到$-$ 4.31天，这表明SN 2021 hpr也可以被归类为HVG SN Ia。SN 2021 hpr的演化与SN 2011 fe相似。包括SN 2021 hpr在内，在宿主星系NGC 3147中已经观测到了6颗超新星，最近50年超新星爆发率在SNe Ia中略高，而在SNe…
