Interstellar Complex Organic Molecules in SiO-traced massive outflows

Abstract

The interstellar medium contains dust and gas, in which at high densities and cold conditions molecules can proliferate. Interstellar Complex Organic Molecules (iCOMs) are C-bearing species that contain at least six atoms. As they are detected in young stellar objects, iCOMs are expected to inhabit the early stages of the star formation evolution. In this study, we try to determine which iCOMs are present in the outflow component of massive protostars. To do this, we analyzed the morphological extension of blue- and red-shifted iCOMs emission in a sample of eleven massive protostars employing mapping observations at one mm within a ~1 GHz bandwidth for both IRAM-30m and APEX telescopes. We modeled the iCOMs emission of the central pointing spectra of our objects using the XCLASS LTE radiative transfer code. We detected the presence of several iCOMs such as: CH3OH, 13CH3OH, CH3OCHO, C2H5C15N, and c-C3H2)CH2. In G034.41+0.24, G327.29-0.58, G328.81+0.63, G333.13-0.43, G340.97-1.02, G351.45+0.66 and G351.77-0.54, the iCOMs lines show a faint broad line profile. Due to the offset peak positions of the blue- and red-shifted emission, covering from ~0.1 to 0.5 pc, these wings are possibly related to movements external to the compact core, such as large-scale low-velocity outflows. We have also established a correlation between the parent iCOM molecule CH3OH and the shock tracer SiO, reinforcing the hypothesis that shock environments provide the conditions to boost the formation of iCOMs via gas-phase reactions.

21 pages, 10 figures, 4 tables, accepted to APJS

References in corpus (12)

• Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• Formation of complex organic molecules in cold objects: the role of gas phase reactions
• ATLASGAL --- towards a complete sample of massive star forming clumps
• Seeds Of Life In Space (SOLIS): The organic composition diversity at 300--1000 au scale in Solar-type star forming regions
• ATLASGAL - Kinematic distances and the dense gas mass distribution of the inner Galaxy
• SiO emission from low- and high-velocity shocks in Cygnus-X massive dense clumps
• Astrochemistry at work in the L1157-B1 shock: acetaldehyde formation
• SiO and CH3CCH abundances and dust emission in high-mass star-forming cores
• Star formation in a clustered environment around the UCHII region in IRAS 20293+3952
• Seeds of Life in Space (SOLIS). X. Interstellar Complex Organic Molecules in the NGC 1333 IRAS 4A outflows
• A SiO J = 5 - 4 Survey Toward Massive Star Formation Regions