Searching for continuum $\gamma$-ray emission from OB associations with INTEGRAL, some preliminary results

Abstract

Recent studies suggested that there might be a correlation between unidentified $\gamma$-ray sources from the third EGRET catalogue and OB associations. Moreover, when extrapolating the fluxes measured by EGRET at energies above 100 MeV with a power-law down to the energy range of ISGRI, the expected count rates should be large enough to be detectable with INTEGRAL. Most of those OB associations being located in the Galactic plane, they are monitored by INTEGRAL as part of the Core Program during both the Galactic Plane Scans and the Galactic Center Deep Exposure. Combining public and CP data, we have performed a search for gamma-ray emission from OB associations and the first results are presented.