La conférence publique Helen Sawyer Hogg

La conférence Helen Sawyer Hogg a été créée en 1985 par la Société canadienne d’astronomie avec la participation de la Société royale d’astronomie du Canada (SRAC), l’Association des planétariums du Canada et l’Institut royal canadien. Depuis, cette conférence publique, supportée conjointement par le fonds de la CASCA et par la SRAC, se tient annuellement au congrès de l’une ou de l’autre des sociétés, en alternance. Elle se veut une reconnaissance des contributions soutenues et diverses de Helen Sawyer Hogg à la prise de conscience du public de l’Univers qui nous entoure. Le choix du conférencier est arrêté par un comité composé des présidents de la CASCA et de la SRAC, ainsi que du président du comité organisateur local, hôte de la rencontre (la CASCA ou la SRAC).

La conférence Helen Sawyer Hogg 2021

Andrea Ghez, University of California, Los Angeles.

From the Possibility to the Certainty of a Supermassive Black Hole

Learn about new developments in the study of supermassive black holes. Through the capture and analysis of twenty years of high-resolution imaging, the UCLA Galactic Center Group has moved the case for a supermassive black hole at the center of our galaxy from a possibility to a certainty and provided the best evidence to date for the existence of these truly exotic objects. This was made possible with the first measurements of stellar orbits around a galactic nucleus. Further advances in state-of-the-art of high-resolution imaging technology on the world’s largest telescopes have greatly expanded the power of using stellar orbits to study black holes. Recent observations have revealed an environment around the black hole that is quite unexpected (young stars where there should be none; a lack of old stars where there should be many; and a puzzling new class of objects). Continued measurements of the motions of stars have solved many of the puzzles posed by these perplexing populations of stars. This work is providing insight into how black holes grow and the role that they play in regulating the growth of their host galaxies. Measurements this past year of stellar orbits at the Galactic Center have provided new insight on how gravity works near a supermassive hole, a new and unexplored regime for this fundamental force of nature.