Quenched massive spiral galaxies have ? ?? ?attracted great attention recently, as more data is available to ? ?? ?constrain their environment and cold gas content. However, the ?? ? ??quenching mechanism is still uncertain, as it depends on the mass ? ?? ?range and baryon budget of the galaxy. In this talk, we report ? ?the ?? ?identification of a rare population of very massive, ? ?quenched spiral ?? ?galaxies with stellar mass ?1011 M⊙ and halo ? ?mass ?1013 M⊙ from the ?? ?Sloan Digital Sky Survey at redshift ? ?z～0.1. Our CO observations ?? ?using the IRAM-30m telescope show ? ?that these galaxies contain only a ?? ?small amount of molecular ? ?gas. Similar galaxies are also seen in the ?? ?state-of-the-art ? ?semi-analytical models and hydro-dynamical ?? ?simulations. It is ? ?found from these theoretical models that these ?? ?quenched spiral ? ?galaxies harbor massive black holes, suggesting that ?? ?feedback ? ?from the central black holes has quenched these spiral ?? ?galaxies. ? ?This quenching mechanism seems to challenge the popular ?? ?scenario ? ?of the co-evolution between massive black holes and massive bulges.

BIO
Xi Kang, the professor at Zhejiang University and the director ? ?? ?of the joint astronomy center between ZJU and Purple Mountain ?? ? ??Observatory, CAS. He got his PhD at Shanghai Astronomical ?? ? ??Observatory in 2005, and worked as a postdoc at the university of ? ?? ?Oxford, Max-Planck-Institute for Astronomy, from 2005-2009. From ? ?? ?2009-2019, He was leading the galaxy and cosmology group at PMO. ? ?? ?From end of 2019, he moved to Zhejiang University and is now ?? ? ??involving the buildup of astrophysics in ZJU.
His main ? ?research ?? ?interest focus on galaxy formation and the large-scale ? ?structure. In ?? ?recent years he has been working on galaxy ? ?alignment on different ?? ?scales, using both N-body simulations and ? ?the observational data. In ?? ?particular, he and his collaborator ? ?proposed the two-stage scenario ?? ?to explain the correlation ? ?between galaxy spin and cosmic filament. ?? ?He is also coordinating ? ?and partly leading the NIHAO project.