1420016

Massive stars and their impacts on their surrounding interstellar medium comprise the feedback scenario which is one of the main astrophysical issues in the context of galaxy and cosmic chemical evolution. Radioactivity from 26Al adds a unique diagnostic tool for studying this scenario in nearby massive-star regions. The Orion region hosts one of the closest such regions at ~400 pc. COMPTELs measurement of 1809 keV emission from this region had shown an interesting offset of the 26Al emission source from its likely sources and emission appears rather extended. This suggests champagne-like outflow into the Eridanus cavity as has recently also been seen with XMM-Newton. If true this opens unique possibilities to study the ISM as it is shaped by massive stars and the interaction of massive stars with their surrounding ISM in a new way: Due to their proximity and location on the near side of molecular clouds and at the edge of a large cavity we can compare the locations of massive stars to the morphology of the ISM and the emission pattern of 26Al radioactivity in order to constrain 26Al ejection from massive stars in mass and velocity. Previous observations led to ~3 Ms of exposure merely enough for a marginal hint of the expected signal. With our proposed deepening of exposure we aim to measure the intensity and kinematics of this nearby 26Al source with INTEGRAL. With these observations we can also search for annihilation radiation and for the intensity of nuclear deexcitation gamma-rays in the MeV range both valuable diagnostics of the structure of superbubble interiors and more than 30 Fermi sources are within our target region. But mainly this will give us unique measurements of ISM dynamics and massive stars as its driving engines within INTEGRALs lifetime there is hardly a more suitable and closer target region. [truncated! Please see actual data for full text]