My research has been focused on galaxy formation, large-scale structure of the universe, and cosmology. I construct models for the formation of disk galaxies, the formation and structure of dark matter halos, the connection between galaxies and dark matter halos, the structure of gaseous halos, and physical processes related to galaxy formation and evolution. I use galaxies and galaxy systems from observations and from simulations to understand the properties of dark matter halos and the distribution of dark matter in the Universe, as well as to reconstruct the current and initial density fields for the local Universe. I have coauthored a textbook on `Galaxy formation and evolution' which was published by Cambridge University Press.
My experience of teaching general astronomy to a big class of non-major students started when I moved to UMass. Before moving to the UMass, my teaching experience was limited to graduate classes, where students already had a relatively strong background in science and mathematics. Teaching a GenEd course really made me to think hard how to explain astronomical phenomena and astrophysical principles to an audience who does not have a strong background in science and mathematics. I set the goals of my teaching to be (1) to get students interested in the subject; (2) to teach them how science works, and (3) to motivate them to have their own explorations of the subject. To achieve these goals, I have made a great effort to connect the astronomical phenomena to be taught to what the students are familiar with, using examples of daily experiences and simple demos. The aim is to show that science is neither mysterious nor too profound to be understood. By making such connections, I encourage the students to appreciate the beauty of science: the same simple principles that govern what we experience daily also govern the motion and evolution of the astronomical objects that are far away. I also believe that it is important to teach the students that astronomy is not only about beautiful images and fascinating phenomena, but also about the physical principles behind them, and about how scientists make inference based on what they can observe but not touch. Whenever possible, I try to make connections between what they learn and what UMass students and researchers have achieved in the past and are doing now, to encourage the students with the fact that some of the real discoveries were and are being made actually not far from them. For this kind of classes, I think the best way is to have clear electronic presentations, so that all students can see the teaching material clearly. For each lecture, I prepare a detailed note about the main points to be covered and make it available to the students on the class website.