A Search For Failed Supernovae and Other Observational Constraints on the Supernova Mechanism

天文学家知道，所有的大质量恒星(质量超过太阳八倍的恒星)，当它们的核心大部分变成铁时，都必须坍塌，它们不再能够通过核聚变产生能量。在大多数情况下，这种坍塌会导致超新星(SN)爆炸，但人们认为一些恒星在没有爆炸的情况下直接坍塌到黑洞，这种结果被称为“失败的超新星”。俄亥俄州立大学的一个研究小组将使用多方面的观测和理论方法来更好地了解大质量恒星的命运和黑洞的形成。为了做到这一点，他们将使用双8.4米大型双筒望远镜(LBT)来监测附近27个恒星形成星系中的所有大质量成熟恒星。这将使他们能够确认第一颗失败的候选超新星，测量SN前体的性质，并探索最微弱的SNE和恒星爆发之间的边界。在这样做的同时，该项目将促进对学生的培训，并扩大公众对恒星科学及其复杂的死亡途径的理解和兴趣。对SNE祖先的研究发现，缺乏高质量的祖先。如果大约20%的核心坍塌失败并产生一个没有SN爆炸的黑洞，就可以解释这种缺陷。这一失败的SN分数也自然地解释了致密物体质量函数。很少有SN前体细胞具有良好的特征，这使得很难确定前体细胞与结果之间的映射关系。俄亥俄州立大学的计划每年将产生大约一名特征良好的祖先。它还将开创对低水平前体可变性的研究，作为对SN搜索的平衡，SN搜索在SN爆炸前不久探测到少量明亮的爆发。该项目还将探索神秘、低光度、类SN天体的后期特性和演化，并可能验证对核心塌陷结果的现代理论调查，这些调查表明，在几个不同的质量范围内存在弱SN。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Astronomers know that all massive stars (stars more than eight times the mass of our Sun) must collapse when their cores become mostly iron and they can no longer generate energy through nuclear fusion. In most cases, this collapse leads to a supernova (SN) explosion, but it is believed that some stars collapse directly to a black hole without exploding, an outcome known as a "failed supernova." A research group at the Ohio State University will use a multifaceted observational and theoretical approach to better understand the fates of massive stars and the formation of black holes. To do this, they will use the twin 8.4-meter Large Binocular Telescope (LBT) to monitor all of the massive, mature stars in 27 nearby star-forming galaxies. This will allow them to confirm the first candidate failed supernova, measure the properties of SN progenitors, and explore the boundary between the faintest SNe and stellar outbursts. While doing so, the project will advance the training of students and broaden the public's understanding and interest in the science of stars and their complicated roads to death.Searches for the progenitors of SNe are finding a deficit of high mass progenitors. This deficit can be explained if about 20% of core collapses fail and produce a black hole without a SN explosion. This failed SN fraction also naturally explains the compact object mass function. Very few SN progenitors are well characterized, making it difficult to determine the mapping between progenitors and outcomes. The Ohio State program will yield roughly one well-characterized progenitor each year. It will also pioneer the study of low-level progenitor variability, as a balance to SN searches that are detecting small numbers of bright outbursts shortly before SN explosions. This project will also explore the late time properties and evolution of mysterious, low luminosity, SN-like objects, and may validate modern theoretical surveys of core collapse outcomes that suggest weak SN occur in several different mass ranges.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.