The Contribution of Millisecond Pulsars to the Isotropic Gamma-Ray Background

The contribution of millisecond pulsars (MSPs) to the Isotropic Gamma-Ray Background (IGRB) could be extremely relevant since they are the second largest population detected at high Galactic latitudes. However, previously theoretical estimates did not carefully take into account Fermi source detectability, and relied on simple models of the MSP sky distribution. I will present the estimate the integrated diffuse emission from MSPs by the integration of their flux distribution, taking into account their Fermi LAT detectability combined with the synthetic evolutionary models of the MSP population. This investigation also provides an estimate of the number of yet unresolved MSPs, useful to constrain their contribution to the Galactic stellar population, and to address the number of future MSPs that could be discovered by Fermi.