effect.

Constraining the Crustal Magnetic Field of the Neutron Star in Kes 79
=====================================================================

We now use the method described in Section 2 to model the X-ray light curve of the NS in Kes 79, thereby constraining the magnetic field configuration in the NS crust.

An internal field of strength similar to the inferred dipole field of the Kes 79 NS would lead to a very uniform temperature distribution on the NS surface (e.g., Schaaf 1990; Potekhin et al. 2003). In order to produce sufficiently concentrated hot spots, we introduce a toroidal (with respect to the dipole axis) component to the magnetic field, such that it is sufficiently large everywhere except in a concentrated region around the magnetic axis. We adopt the following form for the toroidal field: $$\label{Bform}
B_\phi(r,\theta)=B_0f(\theta)g(r),$$ where $B_0$ is an adjustable maximum field strength and $\theta$ is the magnetic colatitude.

Because the NS atmosphere is likely too tenuous to be able to sustain a toroidal field, the toroidal field should be contained entirely in the crust, such that the poloidal current producing it is also contained in the crust. Thus, a realistic form of $g(r)$ should vanish at least at the NS surface, and possibly at 