Multiwavelength analysis of four millisecond pulsars

Radio timing observations of millisecond pulsars (MSPs) in support of Fermi LAT observations of the gamma‐ray sky enhance the sensitivity of high‐energy pulsation searches. With contemporaneous ephemerides we have detected gamma‐ray pulsations from PSR $B1937+21,$ the first MSP ever discovered, and $B1957+20,$ the first known black‐widow system. The two MSPs share a number of properties: they are energetic and distant compared to other gamma‐ray MSPs, and both of them exhibit aligned radio and gamma‐ray emission peaks, indicating co‐located emission regions in the outer magnetosphere of the pulsars. However, radio observations are also crucial for revealing MSPs in Fermi unassociated sources. In a search for radio pulsations at the position of such unassociated sources, the Nançay Radio Telescope discovered two MSPs, PSRs $J2017+0603$ and $J2302+4442,$ increasing the sample of known Galactic disk MSPs. Subsequent radio timing observations led to the detection of gamma‐ray pulsations from these two MSPs as well. We describe multiwavelength timing and spectral analysis of these four pulsars, and the modeling of their gamma‐ray light curves in the context of theoretical models.