Volume 583, November 2015
|Number of page(s)||4|
|Section||Interstellar and circumstellar matter|
|Published online||27 October 2015|
1 Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
2 AlbaNova University Centre, Stockholm University, Department of Astronomy, 106 91 Stockholm, Sweden
Received: 24 June 2015
Accepted: 22 September 2015
Context. The abundance of key molecules determines the level of cooling that is necessary for the formation of stars and planetary systems. In this context, one needs to understand the details of the time dependent oxygen chemistry, leading to the formation of O2 and H2O.
Aims. We aim to determine the degree of correlation between the occurrence of O2 and HOOH (hydrogen peroxide) in star-forming molecular clouds. We first detected O2 and HOOH in ρ Oph A, we now search for HOOH in Orion OMC A, where O2 has also been detected.
Methods. We mapped a 3′×3′ region around Orion H2-Peak 1 with the Atacama Pathfinder Experiment (APEX). In addition to several maps in two transitions of HOOH, viz. 219.17 GHz and 251.91 GHz, we obtained single-point spectra for another three transitions towards the position of maximum emission.
Results. Line emission at the appropriate LSR-velocity (Local Standard of Rest) and at the level of ≥4σ was found for two transitions, with lower signal-to-noise ratio (2.8−3.5σ) for another two transitions, whereas for the remaining transition, only an upper limit was obtained. The emitting region, offset 18′′ south of H2-Peak 1, appeared point-like in our observations with APEX.
Conclusions. The extremely high spectral line density in Orion makes the identification of HOOH much more difficult than in ρ Oph A. As a result of having to consider the possible contamination by other molecules, we left the current detection status undecided.
Key words: astrochemistry / ISM: general / ISM: individual objects: Orion H2-Peak 1 / ISM: molecules / ISM: abundances / stars: formation
Based on observations with APEX, which is a 12 m diameter submillimetre telescope at 5100 m altitude on Llano Chajnantor in Chile. The telescope is operated by Onsala Space Observatory, Max-Planck-Institut für Radioastronomie (MPIfR), and European Southern Observatory (ESO).
The final reduced data cube (FITS files) is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/583/A53
© ESO, 2015
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