GUAPOS III. O- and N-bearing complexes

The observations were carried out with the interferometer ALMA and cover the entire Band 3 from 84 to 116GHz (~32GHz bandwidth) with an angular resolution of 1.2"x1.2" (~4400aux4400au) and a spectral resolution of ~0.488MHz (~1.3-1.7km/s). The transitions of the fourteen molecular species have been analyzed with the tool SLIM of MADCUBA to determine the physical parameters of the emitting gas. Moreover, we have analyzed the morphology of the emission of the molecular species.

The values of abundances w.r.t H_2_ in G31 range from 10^-6^ to 10^-10^ for the different species. We have compared the abundances w.r.t methanol of O-bearing, N-bearing, and O- and N-bearing COMs in G31 with other twenty-seven sources, including other hot molecular cores inside and outside the Galactic Center, hot corinos, shocked regions, envelopes around young stellar objects, and quiescent molecular clouds, and with chemical models.

From the comparison with other sources there is not a unique template for the abundances in hot molecular cores, pointing towards the importance of the thermal history for the chemistry of the various sources. The abundances derived from the chemical models are well in agreement, within a factor ten, with those of G31. From the analysis of the maps we derived the peak positions of all the molecular species toward G31.

Different species peak at slightly different positions, and this, together with the different central velocities of the lines obtained from the spectral fitting, point to chemical differentiation of selected O-bearing species.