Light-curve modelling constraints on the obliquities and aspect angles of the young Fermi pulsars

Understand

In more than four years of observation the Large Area Telescope on board the Fermi satellite has identified pulsed $\gamma$-ray emission from more than 80 young pulsars, providing light curves with high statistics.

• Fitting the observations with geometrical models can provide estimates of the magnetic obliquity $\alpha$ and aspect angle $\zeta$, yielding estimates of the radiation beaming factor and luminosity.
• Using $\gamma$-ray emission geometries (Polar Cap, Slot Gap, Outer Gap, One Pole Caustic) and radio emission geometry, we fit $\gamma$-ray light curves for 76 young pulsars and we jointly fit their $\gamma$-ray plus radio light curves when possible.
• We find that a joint radio plus $\gamma$-ray fit strategy is important to obtain ($\alpha$, $\zeta$) estimates that can explain simultaneous radio and $\gamma$-ray emission.