Chemical Complexity in the Galactic Centre Molecular Clouds
Dr Miguel Angel Requena Torres
Dpto. Astrofisica Molecular e Infrarroja,
Instituto de Estructura de la Materia (CSIC)
4-5 p.m., Thursday, 16 August 2007
Physics Lecture Theatre, Old Main Building (K15),
The University of New South Wales
The physical and the chemical properties of the molecular clouds in the centre of the Galaxy are very different to those in the Galactic disk. The Galactic center is an outstanding region where extreme physical processes are taking place. It constitutes a unique laboratory for studying the effects on the chemical complexity produced by energetic events like supernova remnants, photo-dominated regions, highly turbulent medium, high mass star formation or the presence of a black hole. One of the more interesting processes is the presence of widespread shocks, which produce a dramatic change of the gas phase abundances by the ejection of complex molecules from the grain mantles. This affects the chemistry in these regions, in a manner similar to that which occurs in "hot molecular cores", where grain mantles are evaporated due to the warming induced by protostars.
The IRAM 30-m and the Green Bank telescopes have been used to establish the limit of the chemical complexity found in the Galactic centre. We find very large abundances of complex organic molecules, even higher than those observed in hot cores. The similar relative abundances between molecules suggest a 'uniform' mantle composition for the Galactic centre clouds. The region is a laboratory to study the chemistry of complex organic molecules.
The results obtained in this work open several lines of investigations aimed at understanding the physics and chemistry that control the chemical complexity found in molecular clouds in the Galaxy.