Studying the molecular ambient towards the young stellar object EGO G35.04-0.47

Abstract

We are performing a systematic study of the interstellar medium around extended green objects (EGOs), likely massive young stellar objects driving outflows. EGO G35.04-0.47 is located towards a dark cloud at the north-western edge of an H II region. Recently, H2 jets were discovered towards this source, mainly towards its south-west, where the H2 1-0 S(1) emission peaks. Therefore, the source was catalogued as the molecular hydrogen emission-line object MHO 2429. In order to study the molecular ambient towards this star-forming site, we observed a region around the aforementioned EGO using the Atacama Submillimeter Telescope Experiment in the 12CO J = 3-2, 13CO J = 3-2, HCO+ J = 4-3, and CS J = 7-6 lines with an angular and spectral resolution of 22´´ and 0.11 km s-1, respectively. The observations revealed a molecular clump where the EGO is embedded at vLSR ? 51 km s-1, in coincidence with the velocity of a Class I 95 GHz methanol maser previously detected. Analyzing the 12CO line we discovered high velocity molecular gas in the range from 34 to 47 km s-1, most likely a blueshifted outflow driven by the EGO. The alignment and shape of this molecular structure coincide with those of the south-west lobe of MHO 2429, mainly between 46 and 47 km s-1, confirming that we are mapping its CO counterpart. Performing a spectral energy distribution analysis of EGO G35.04-0.47, we found that its central object should be an intermediate-mass young stellar object accreting mass at a rate similar to those found in some massive YSOs. We suggest that this source can become a massive YSO.