Pulsar death line and ultra long period pulsars

It is widely believed that pulsars and magnetars can produce coherent radio emission while electron-positron plasma is being continuously created in their magnetospheres; the radio emission ceases when pair formations stops. Recent discovery of a new class of objects - ultra long period pulsars - challenges existing theoretical predictions for pulsar death line - values of key pulsar parameters, such as period and strength and geometry of the magnetic field, when pair creation becomes impossible. Here I re-examine the conditions under which pulsars and magnetars are able to produce pair plasma taking into account modern theories for particle acceleration and pair production in neutron star magnetospheres.