The complexity of Orion : an ALMA view II. gGg '-ethylene glycol and acetic acid

CF acknowledges support from the Italian Ministry of Education, Universities and Research, project SIR (RBSI14ZRHR). The authors thank Hannah Calcutt for providing the acetic acid partition function. We also thank Melvyn Wright and Rick Plambeck for their HC3N emission map. This work was carried out in part at the Jet Propulsion Laboratory, which is operated for NASA by the California Institute of Technology. MC acknowledges financial funding from the project FIS2014-53448-C2-2-P (MINECO, Spain), and CMST COST Action CM1405 MOLIM. CF and MC acknowledge support from CMST COST Action CM1401 Our Astro-Chemical History. LP thanks Arnaud Belloche and H.S.P. Muller for their help with molecular spectroscopy data. CF thanks Claudio Codella for an enlightening discussion on shocks. Finally, CF thanks Vianney Taquet and Franck Hersant for a fruitful discussion about the binding energies and acetic acid formation routes. This paper makes use of the following ALMA data: ADS/JAO. ALMA#2013.1.00533. S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.