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Detecting gamma-rays from microquasars is a challenging but worthwhileendeavor for understanding particle acceleration, the jet mechanism, and forconstraining leptonic/hadronic emission models. We present results from alikelihood analysis on timescales of 1 d and 10 d of ~4 years worth ofgamma-ray observations (0.1-10 GeV) by Fermi-LAT of Cyg X-1, Cyg X-3, GRS1915+105, and GX 339-4. Our analysis reproduced all but one of the previousgamma-ray outbursts of Cyg X-3 as reported with Fermi or AGILE, plus 5 new dayson which Cyg X-3 is detected at a significance of ~5-sigma that are notreported in the literature. In addition, Cyg X-3 is significantly detected on10-d timescales outside of known gamma-ray flaring epochs which suggests thatpersistent gamma-ray emission from Cyg X-3 has been detected for the firsttime. For Cyg X-1, we find three low significance excesses (~3-4-sigma) ondaily timescales that are contemporaneous with gamma-ray flares reported (alsoat low significance) by AGILE. Two other microquasars, GRS 1915+105 and GX339-4, are not detected and we derive 3-sigma upper limits of 2.3e-8 ph/cm2/sand 1.6e-8 ph/cm2/s, respectively, on the persistent flux in the 0.1-10 GeVrange. These results enable us to define a list of the general conditions thatare necessary for the detection of gamma-rays from microquasars.

Gamma-ray observations of the microquasars Cygnus X-1, Cygnus X-3, GRS 1915+105, and GX 339-4 with the Fermi Large Area Telescope