Discovery of $γ$-Ray Pulsations from the Extreme-Spin-Down Millisecond Pulsar PSR J0435+3233
Motivated by the recent discovery of PSR~J0435+3233, a millisecond pulsar with an exceptionally large period derivative of $\dot{P}=4.9\times10^{-17}\ {\rm s\,s^{-1}}$ and a high spin-down luminosity of $\dot{E}=5.89\times10^{37}\ {\rm erg\,s^{-1}}$, we analyze $\sim$17~yr of observations obtained with the \textit{Fermi} Large Area Telescope for the pulsar. We identify the cataloged source 4FGL~J0435.5+3232, located only $0.01^{\circ}$ from the radio timing position, as the $γ$-ray counterpart o…