The traditional, geometrical rotating vector model (RVM) has proved particularly poor at capturing the polarization sweeps of the young energetic and millisecond pulsars detected by \textit{ Fermi}. We augment this model by including finite altitude effects using a swept back vacuum dipole geometry. By further including the effects of orthogonal mode jumps, multiple emission altitudes, open zone growth via y-point lowering, and interstellar scattering, we show that a wide range of departures from RVM can be modeled well while retaining a geometrical picture. We illustrate these effects by fitting six \textit{ Fermi}-detected pulsars (J0023$+$0923, J1024$-$0719, J1744$-$1134, J1057$-$5226, J1420$-$6048, and J2124$-$3358) and we describe how such modeling can improve our understanding of their emission geometry.
Categories: astro-ph.HE