AGILE gamma-ray detection of Cygnus X-1

Following the MAXI/GSC detection of a new soft X-ray brightening in Cygnus X-1 (ATel #2711) and the subsequent X-ray increased emission reported by RXTE-ASM (ATel #2714), indicating a possible transition of the source to the soft spectral state, we carried out follow up analysis for gamma-ray emission in AGILE data. Integrating from 2010-06-30 10 00 UT to 2010-07-02 10 00 UT, a maximum likelihood analysis yields a flux excess above 100 x 10-8 ph/cm2/s (E > 100 MeV) in a position consistent with the black hole binary Cygnus X-1.