Time Domain Astrophysics

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Supernovae, time-domain astronomy, gamma-ray bursts, and the expansion of the Universe

We are involved primarily in observational studies of stellar explosions at optical, ultraviolet, and near-infrared wavelengths. Most of my data are obtained with the Xinglong 2.16-meter reflector, the Lijiang 2.4-meter reflector, the 0.8-m Tsinghua University reflector, the Antarctic Survey Telescope, and the Swift satellite, though I also utilize the data from Keck 10-meter telescope and other observing facilities through my collaborators. In addition, my group has developed a wide-field survey program using the 0.6-meter schmidt telescope at Xinglong Observatory (TNTS, the Tsinghua University-NAOC Transient Survey), with a goal to search for different types of transients in the local universe, including supernovae, variable stars, novas, and active galactic nuclei/quasars etc. (see We are going to establish the survey network with some wide-field telescopes at other sites in China. Our collaborators and we are making an effort to determine the nature of the progenitor stars, the explosion mechanisms of different types of supernovae (in particular type Ia supernovae). With TNTS, we have successfully discovered nearly 100 SNe over the past 2 years. We have spectroscopically classified most of them and made extensive follow up observations for some interesting ones, which provides a rich data base for individual and statistical studies. Our recent work shows the spectroscopic diversity of SNe Ia is tied to their birth environments, suggesting that there are perhaps multiple channels leading to the explosion of type Ia supernovae. This is a very important result for the studies of SN Ia progenitors and precision cosmology with SNe Ia (Wang et al. Science, 2013, 340, p170-173).

Contact: Xiaofeng Wang
Gravitational microlensing and extrasolar planets

Gravitational microlensing refers to the apparent brightening of a background source caused by a lensing object located sufficiently close to the line of sight. Microlensing in the Galaxy has been found to have diverse applications, for example, it can be used to study the Galactic structure, stellar atmospheres and discovery extrasolar planets. We are particularly interested in making predictions what next-generation microlensing surveys can reveal in the context of core accretion theory of planet formation.

Contact: Shude Mao