Tackling Radio Polarization of Energetic Pulsars

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 $\mathit{\text{Fermi}}$. 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 $\mathit{\text{Fermi}}$-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.