报告摘要：Supernovae are related to many frontiers of astrophysics, i.e., from probes of extreme physics to discovery of accelerating unvierse. Their distribution and birth rates can help constrain progenitor models and stellar evolution theory. Thanks to the wide-field transient surveys conducted over the past decade, the discovery of nearby supernovae tends to be relatively complete. We compiled a nearby SN sample, including 211 SNe discovered at distances < 40 Mpc over the years from 2016 to 2023, and derived fractions of different types and subtypes, rates and their dependence on environments. The new sample gives a fraction of 30.4% and 69.6% for type Ia and core-collapse SNe, respectively, and the fraction of SNe Ia increased by about 26% relative to previous estimates. In particular, the SN Ia rate shows a prominent increase from redshift z~0.1 to z<0.01, revealing a unique double peak distribution in Sc- and E/S0-type galaxies. Such a distinct distribution suggests the presence of a "prompt" channel and the other one with a delayed time up to 12.6+/-0.4 Gyr, and the latter channel with a fraction of at least one third comes likely from merging explosion of double white dwarfs. Based on our updated determinations, we estimate the SN rate as 3.1+/-1.3 per century for the MilkyWay.
主讲人简介：Dr. Xiaofeng Wang is a professor of physics department at Tsinghua University. He got his bachelor's degree in astrophysics in 1997 and PhD in 2002 from Beijing Normal University. He ever worked as a postdoctoral researcher at NAOC, UC Berkeley and Texas A&M University, focusing on studies of supernovae and time-domain astronomy. Since 2010 Prof. Wang joined Tsinghua University, where he has led several transient survey projects, leading to discovery of lots of supernovae, variables and binaries. In 2013 he was selected to "The National Science Fund for Distinguished Young Scholars"; in 2015, he was awarded the "Shoushu Huang" prize by the Chinese Astronomical Society; in 2021 he won the Tencent Xplorer Prize. Prof. Xiaofeng Wang has published over 210 papers with his collaborators (including 10 in Science, Nature and Nature Astronomy), receiving 14,000+ citations.
