The mystery of lost pulsars.

"Radio detection of an elusive millisecond pulsar, PSR J1740-5340B (NGC 6397B), in the Globular Cluster NGC 6397 with the Parkes radio telescope in Australia. Credit: NAOC/ScienceApe" (ScitechDaily.com/Why Have Pulsars “Gone Missing” – A New Finding Offers Some Answers)

Pulsars are fast-rotating neutron stars. And that means many forces affect that thing. There is the possibility that the extremely fast rotating neutron stars will stretch from their poles. And the neutron star turns to look a little bit like a dumbbell. That change in the form of neutron stars is not quite big but researchers can measure that change. 

Pulsars can turn away from the Earth. And that means they can be "missing". The changes in material symmetry can cause the pulsar will get an extra dose of positive or negative particles. So in that case the asymmetry in electricity of particles that impact with neutron star can cause the pulsar changes its position. 

All pulsars are neutron stars. The neutron star is a supernova remnant and molecular nebula surrounds neutron stars at least at the beginning of their existence. The radiation of the pulsar forms when particles impact the neutron star. There is the possibility that a neutron star blows its molecular nebula away. And that turns it invisible. 

One reason why pulsar is missing can be it simply turned away from the Earth. Or some pulsars are hard to detect. Because their radiation is turning to Earth all the time. In that case, the radiation of the pulsar continues all the time. Normally pulsars are detected because there are pauses in their radiation. 

When we think about extremely short-period pulsars like millisecond pulsars there is the possibility that those pulsars are just wobbling. That means their poles are moving only a little and that thing causes that pulsar will point to Earth for only a short time. The pulsar's radiation comes mainly out from the poles of the neutron star. So in this text pulsar and neutron star are the same. 

Or maybe we should say that neutron star. That sends radiation is a pulsar. 

All neutron stars are not sending radiation. If a neutron star is in a cosmic bubble, no material impacts them. Radiation of the neutron star comes from high-energy particle impacts to its core. And that's why molecular nebulas are important for making pulsars visible. 

There is one thing that can explain why some pulsars are missing. 

Pulsar radiowaves are born when material falls to a neutron star. When that material impacts that massive object it releases energy as radio waves. When particles impact with a neutron star. They face an extremely strong magnetic field that drives those particles to the poles of the neutron star. The radiation leaves the neutron star in the form of two narrow beams. 

There is the possibility that a neutron star just blows particles away from it. If no gas and dust can impact it no radiation can form in those impacts. So if neutron stars are just making the bubble around them that thing can cause they will be lost. 

But in some scenarios neutron stars are putting the nebula around them to shine so bright that the radiowaves cannot travel across that cloud. When molecular nebula around neutron star gets radiation the particles will sooner or later start to send emission radiation. When the particles are sending radiation the energy level is higher than the radiation that comes from the neutron star that radiation will close the pulsar in it. 

The thing is that the molecular cloud or particles of the molecular cloud around the neutron star or pulsar can send radiation only when their energy level rises higher than the energy that comes from the pulsar. So that thing can turn the molecular cloud into the giant Faraday cage that keeps the radiation of the neutron star inside it. 

Image and other sources. 

https://scitechdaily.com/why-have-pulsars-gone-missing-a-new-finding-offers-some-answers/