However, these cooling regulators are usually not as strong as neutrino emission from the core.

The effects of superfluidity can be more sophisticated than described above. Taking different EOSs \[different direct Urca thresholds and $T_{\rm c}(\rho)$ profiles\] one can obtain a complicated zoo of families of cooling neutron stars [@kaminkeretal06a; @gkyg05]. Neutrino emission due to Cooper pairing of baryons can affect the cooling in many ways as reviewed in Refs. [@yp04; @pgw06]. In particular, a moderately strong neutron superfluidity in the nucleon core can enhance the neutrino luminosity over the modified Urca level by a factor of $\sim$30, allowing one to explain the coldest observed sources by neutrino emission from the nucleon (non-exotic) core without invoking the direct Urca process. This leads to the scenario of “minimal cooling” [@pageetal04; @gusakovetal04].

Cooling of neutron stars can be accompanied by some reheating associated, for instance, with the dissipation of differential rotation, deviation from beta-equilibrium or decay of magnetic fields in neutron star interiors. The magnetic reheating can be especially strong in magnetars (see below). Otherwise these reheating mechanisms are expected to be significant in old neutron stars (at the photon cooling stage). They are reviewed in [@yp04; @pgw06].

Finally, we have not 