Complejidad química en las nubes moleculares del centro de la galaxia

Résumé

The physical and the chemical properties of the molecular clouds in center of the Galaxy are very different than those in the Galactic disk. The Galactic center (GC), a very outstanding region, where very extreme physical processes are taken place, constitutes an unique laboratory for studying the effects on the chemical complexity produced by the energetic events like supernova remnants, photo-dominated regions, highly turbulent medium, high mass star formation or the presence of a black hole. The IRAM 30-m and the Green Bank telescopes have been used to establish that the limit of the chemical complexity in the Universe is found in the GC. In this work several regions distributed in a 200pc region along the Galactic plane have been studied in detail. There we have studied complex organic molecules (COMs) containing mainly C, O and H, that cover several families, like the alcohols or the aldehydes containing up to 3 carbon atoms. It has been found that these COMs show very large abundances respect to H2 in the GC regions, even higher than the observed in Galactic hot cores, where these molecules where suppose to be formed. Therefore the GC is one of the best laboratories to study the properties of the chemistry of these complex molecules. Moreover, the results show that the actual chemical models can not predict the observed abundances and that the comparison between the CO, CS and HNCO molecules can be a good tracer for the regions where the UV photons destroy the complex molecules, not only in our Galaxy center, but in external galaxy nuclei.