Anomalous absorption in glycolaldehyde in a cosmic object

作者：Sharma M K; Sharma A K; Sharma M; Chandra S

来源：New Astronomy, 2016, 45: 45-47.

DOI：10.1016/j.newast.2015.10.005

• ISM: Molecules
• Glycolaldehyde
• Einstein A-coefficients
• Radiative transfer

The glycolaldehyde is detected towards the Galactic center source Sgr B2(N) and towards the massive star forming region G31.41+0.31 through b-type transitions. The levels for b-type transitions can be classified into two groups: (i) with k(a) + k(c) = odd (set I) and (ii) with k(a) + k(c) = even (set II). For each of the sets I and II, we have calculated energies of 100 rotational levels. These levels are connected through radiative and collisional transitions. The Einstein A-coefficients for the radiative transitions among the levels are calculated. The collisional rate coefficients are calculated with the help of a scaling law. Using the radiative and collisional transitions probabilities, for each of the sets I and II, we have solved a set of statistical equilibrium equations coupled with the equations of radiative transfer. Two transitions 1(10)-1(01) and 3(12) - 3(03) at 13.477 GHz and 17.981 GHz, respectively, of set I, and one transition 2(11) - 2(02) at 15.176 GHz of set II are found to have anomalous absorption. These transitions may play important role in the identification of glycolaldehyde in a cosmic object.

• 出版日期2016-5