Analysis of C2H4O2 Isomers in NGC 6334 I

We have analyzed the abundances of the three isomers methyl formate (CH3OCHO), glycolaldehyde (cis-CH2OHCHO), and acetic acid (CH3COOH) in the NGC 6334 I-MM1 and -MM2 massive star-forming regions using Atacama Large Millimeter/submillimeter Array (ALMA) data. In the MM1 star-forming region, we derived column densities of 9.93 (0.94) e17 cm-2 for methyl formate, 1.24 (0.16) e17 cm-2 for acetic acid, and 9.31 (0.68) e15 cm-2 for glycolaldehyde. In the MM2 star-forming region we derived column densities of 9 (1) e18 cm-2 for methyl formate and 1.48 (0.25) e17 cm-2 for acetic acid. An upper limit of 1.15 e16 cm-2 was calculated for the column density of glycolaldehyde in MM2. These abundances are compared to other star-forming regions and theories on the chemical reasons for their differences are presented.