The dust enrichment of galaxies: supernovae and evolved stars

超新星在天体物理学中占有举足轻重的地位，不仅因为它们作为标准烛光和宇宙探测器的重要性，还因为它们在确定星系的整体能量学、质量再循环率和重元素富集方面发挥着主要作用。据推测，超新星（SNe）可能是宇宙中尘埃粒子的主要来源，甚至是主要来源。对这一假设的间接支持来自这样一个事实，即许多已知的最早形成的星系是极其多尘和红外发光的，这一点由水肺和其他仪器对它们的亚毫米波长红移尘埃发射的有效探测证明。似乎只有大质量恒星才能在暗示的短时间尺度内产生观测到的尘埃，要么是在SN事件之前的尘埃质量损失阶段，要么是在SN事件的膨胀和冷却喷射物中。尘埃形成模型证实，在爆发后1-2年内，SN喷出物中新形成的尘埃应该在中红外波段被探测到，中红外波段特别适合追踪SNe中尘埃形成的开始，并确定尘埃形成的数量。随着地面8米望远镜的出现，配备了灵敏的中红外仪器，如双子座的米歇尔和trec，以及斯皮策太空望远镜（SST）的发射，足够的灵敏度已经可以用来搜索附近星系中超新星的中红外辐射。来自北美和欧洲的天文学家组成了我们的SEEDS合作项目（超新星星系外尘埃发射调查），利用IRAC和MIPS仪器，在超新星爆发数百天后，获得了寻找附近超新星中红外尘埃发射的SST时间。此外，我们还访问了使用相同仪器获得的一些附近星系的sing Legacy SST数据，以便在这些星系中搜索最近SNe的中红外发射。该提案寻求继续博士后资助，以便完成超新星尘埃项目。此外，作为欧空局2007年发射的赫歇尔空间天文台保证时间观测的一部分，新的远红外和亚毫米测绘观测将获得演化恒星周围扩展的尘埃壳，目的是解决低质量和中等质量恒星的“缺失质量”问题。

Supernovae occupy a pivotal position in astrophysics, not only because of their importance as standard candles and cosmological probes but also because of the prime role that they play in determining the overall energetics, mass recycling rate and heavy-element enrichment of galaxies. It has been hypothesised that supernovae (SNe) may be a major, or even dominant, source of dust particles in the Universe. Indirect support for this supposition comes from the fact that many of the earliest-formed galaxies known are extremely dusty and IR-luminous, as evidenced by the efficient detection of their redshifted dust emission at submillimetre wavelengths by SCUBA and other instruments. It seems that only massive stars can have produced the observed dust over the short timescales implied, either during during dusty mass-losing phases prior to the SN event or else within the expanding and cooling ejecta from the SN event. Dust formation models confirm that newly formed dust in SN ejecta should become detectable at mid-IR wavelengths within 1-2 years of outburst and that the mid-IR is particularly suitable to trace the onset of dust formation in SNe and to determine the amount of dust formed. With the advent of ground-based 8-m telescopes equipped with sensitive mid-IR instruments, such as Gemini's Michelle and TReCS, and the launch of the Spitzer Space Telescope (SST), sufficient sensitivity has become available to embark on searches for mid-IR emission from supernovae in nearby galaxies. Our SEEDS collaboration (Survey for Extragalactic Emission from Dust in Supernovae), composed of astronomers from North America and Europe, has obtained SST time to search for mid-IR dust emission from nearby supernovae hundreds of days after their outbursts, using the IRAC and MIPS instruments. In addition, we have accessed SINGS Legacy SST data on a number of nearby galaxies that have been obtained with the same instruments, in order to search for mid-IR emission from recent SNe within these galaxies. This proposal seeks continued postdoctoral funding in order to allow completion of the supernova dust project. In addition, new far-infrared and submillimetre mapping observations of extended dust shells around evolved stars will be obtained as part of Herschel Space Observatory Guaranteed Time observations following its launch by ESA in 2007, with the aim of addressing the `missing mass' problem for low and intermediate mass stars.