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3D Observations of Molecular Gas in Galaxies: From Global Dynamics to Supermassive Black Holes


Speaker:Prof. Martin Bureau
Affiliation:University of Oxford
Date:May 24, 2017 (Wednesday)
Time:2:30 p.m.
Venue:Room 522, 5/F, Chong Yuet Ming Physics Building, HKU

Abstract
 

I will first briefly review the molecular gas content of early-type galaxies. I will show not only that they unexpectedly harbour much cold gas, but also that it is the best tracer of the circular velocity, thus allowing accurate spatially-resolved dynamical mass measurements in galaxies across the Hubble sequence. Second, I will explore the use of molecular gas for studies of the Tully-Fisher (luminosity-rotational velocity) relation of galaxies to high redshifts. I will highlight the work done to establish local (z=0) benchmarks and will discuss the challenges posed by systematic effects when comparing nearby and distant galaxies. Third, I will demonstrate that CO can be used to easily and accurately measure the mass of the supermassive black holes lurking at galaxy centres. I will discuss substantial ongoing efforts to do this and present many spectacular new ALMA measurements, that open the way to literally hundreds of measurements across the Hubble sequence with a unique method. I will also hint at how the same data allow to study the spatially-resolved properties of giant molecular cloud populations in non-local galaxies for the first time, providing a new tool to understand and contrast the star formation efficiency of galaxies on cloud scale.
 
Coffee and tea will be served 20 minutes prior to the seminar.

Anyone interested is welcome to attend.