Spectral line surveys reveal rich molecular reservoirs in G331.512-0.103 , a compact radio source in the center of an energetic molecular outflow .
In this first work , we analyse the physical conditions of the source by means of CH _ { 3 } OH and CH _ { 3 } CN . The observations were performed with the APEX telescope .
Six different system configurations were defined to cover most of the band within ( 292–356 ) GHz ; as a consequence we detected a forest of lines towards the central core . A total of 70 lines of A / E -CH _ { 3 } OH and A / E -CH _ { 3 } CN were analysed , including torsionally excited transitions of CH _ { 3 } OH ( \nu _ { t } =1 ) .
In a search for all the isotopologues , we identified transitions of ^ { 13 } CH _ { 3 } OH .
The physical conditions were derived considering collisional and radiative processes .
We found common temperatures for each A and E symmetry of CH _ { 3 } OH and CH _ { 3 } CN ; the derived column densities indicate an A / E equilibrated ratio for both tracers . The results reveal that CH _ { 3 } CN and CH _ { 3 } OH trace a hot and cold component with T _ { k } \sim 141 K and T _ { k } \sim 74 K , respectively .
In agreement with previous ALMA observations , the models show that the emission region is compact ( \lesssim 5.5 \arcsec ) with gas density n ( H _ { 2 } ) = ( 0.7–1 ) \times 10 ^ { 7 } cm ^ { -3 } .
The CH _ { 3 } OH/CH _ { 3 } CN abundance ratio and the evidences for pre-biotic and complex organic molecules suggest a rich and active chemistry towards G331.512-0.103 .