Observations and Theory of Supernovae

惠勒，J.克雷格95-28110 惠勒博士将结合使用光度学和光谱学，包括旋光学，以更好地了解祖先的演变，爆炸机制和使用超新星作为宇宙学探针。 探索的一个特别主题是IC型超新星，它们似乎缺乏大部分氢和氦包层，这是其祖先进化的关键线索。 其中一些事件的光变曲线相当浅，类似于SN 1993 J等其他事件，但光谱演化却相当不同，而另一些则具有更陡峭的光变曲线。 这可能为这些事件的坍缩、聚集、混合和爆发的性质提供线索。 还将继续进行的是超新星偏振测量计划，该计划有望提供有关喷出物性质和星周环境的关键信息。 初步的结果是Ia型超新星是非极化的，这意味着一个近似球形的喷出物和很少的星周散射，但II型，也许所有的坍缩事件，有有限的极化，这意味着大量的不对称的喷出物或星周物质。 最后，观测计划包括三个超新星搜索计划，一个是用新的专用超新星搜索望远镜对附近明亮的超新星进行视觉搜索，一个是在红移Z约为0.1的情况下确定可能的星系演化效应，一个是在Z约为1的情况下进行深度调查以约束宇宙学模型。 观测计划将辅以协调的理论研究。 这些将包括热核爆炸的多维模型，包括爆燃火焰和爆炸结构和稳定性以及多维和多能量群中微子输运的引力坍缩。 还将计算模型的光谱演变，以与观测结果进行比较。 特别令人感兴趣的是光谱演化的模型，再现光曲线速度，颜色和最大亮度与Ia型超新星的色散。 ***

Wheeler, J. Craig 95-28110 Dr. Wheeler will use a combination of photometry and spectroscopy, including polarimetry, to better understand the progenitor evolution, the explosion mechanism and the use of supernovae as cosmological probes. A particular topic of exploration will be Type Ic supernovae which seem to be devoid of most of their hydrogen and helium envelopes, a critical clue to their progenitor evolution. Some of these events have rather shallow light curves resembling other events like SN 1993J with rather different spectral evolution and some have steeper light curves. This may give clues to the nature of the collapse, clumping, mixing, and explosion of these events. Also to be continued is the program of supernova polarimetry, which promises critical information concerning the nature of the ejecta and of the circumstellar environment. Preliminary results are that Type Ia supernovae are unpolarized, implying a nearly spherical ejecta and very little circumstellar scattering, but that Type II, and perhaps all collapse events, have finite polarization, implying substantial asymmetries in the ejecta or circumstellar matter. Finally, the observational program includes three supernova search programs, one a visual search for nearby bright supernovae with the newly dedicated Supernova Search Telescope, one at redshifts of Z about 0.1 to determine possible galaxy evolution effects, and one deep survey at Z about 1 to constrain cosmological models. The observing program will be complemented with coordinated theoretical investigations. These will include multi-dimensional models of thermonuclear explosions, including deflagration flames and detonation structure and stability and gravitational collapse with multi-dimensional and multi-energy group neutrino transport. Also computed will be the spectral evolution of models to compare with observations. Of special interest is the spectral evolution of models that reproduce the dispersion of light curve speed, color and maximum brightness associated with Type Ia supernovae. ***