Understanding the physics of the interstellar medium is critical for understanding star formation and AGN feedback. Line ratio diagnostics diagrams, such as BPT diagrams, have been extensively used to study the ISM. However, their limitations hide inaccuracies of photoionization models, leading to a number of discrepant results in the literature on metallicity, abundance pattern, and correlations between metallicity and ionization parameters. We present a new perspective about line ratio diagnostics that would help resolve these discrepancies and constrain the undertested assumptions in photoionization models. It also helped us discover surprisingly that the dust attenuation correction of forbidden lines are different from our past expectations. This new perspective should pave the road towards an era in which we can model the astrophysics of the warm ionized gas with precision, in the same style as precision cosmology. I will also introduce the design of a cost-effective, high spectral resolution, integral field spectrograph. When paired with a small telescope like a telephoto lens or arrays of them, it could provide unprecedented data to help us better understand star-forming HII regions and the feedback of star formation.
Prof. Renbin Yan got his bachelor degree from Peking University and his PhD from University of California at Berkeley. After that, he was a postdoctoral scholar at the University of Toronto and New York University. In 2012, he joined the faculty at the University of Kentucky and was tenured in 2018. Last year, he joined the Chinese University of Hong Kong and was awarded the title of Global STEM Scholar. Prof. Yan's research interest includes the astrophysics of the interstellar medium, stellar population, and astronomical instrumentation. He is experienced at conducting large spectroscopy surveys. He is the survey scientist of the SDSS-IV/MaNGA project, which is the largest integral field spectroscopy survey of galaxies to date, providing data for 10,010 unique galaxies. He also leads the MaNGA Stellar Library project, which is the largest and most-comprehensive stellar library to date. Recently, he is starting a new astronomical instrumentation project to build instruments for the next generation spectroscopy surveys.
Host: Cheng Li