Astronomy Colloquium (2018 Fall Semester)

* Date.         Nov 01

* Speaker.   Martin Bureau (Oxford University)

* Title.         WISDOM: Probing Supermassive Black Holes and their Immediate Environments with ALMA

* Abstract 

I will present key results from the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM), a high resolution survey of molecular gas in galaxy nuclei. First, I will show 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, the latest of which rival the best black hole measurements to date. This opens the way to literally hundreds of measurements across the Hubble sequence (in both active and non-active galaxies) with a unique method. Second, I will show how the same data allow to study the spatially-resolved properties of the giant molecular clouds in all the galaxies studied. This will yield cloud censuses in non-local galaxies (including early-type galaxies) for the first time, providing a new tool to understand and contrast the star formation efficiency of galaxies. Already, it appears that basic cloud properties are not universal and vary systematically along the Hubble sequence, contrary to long-held assumptions.