A Pulsar is the highly magnetised and extremely dense remains of a star that has collapsed to a diameter of typically 10 miles and spins on its axis at an incredible rate of up to 500Hz emitting a beam of radiation from its magnetic polar axis which is typically inclined at an angle to the spin axis.
At a Pulsar’s surface the gravitational field is so strong that an object dropped one metre would accelerate to over 4,000mph!
Fig 1: Pulsars with radiation emitted from the magnetic poles
The first pulsar was discovered in 1967 using a radio telescope as an extremely regular “blip” of radiation.
The “holy grail” of pulsar research is the Binary Pulsar where a Pulsar is in orbit around the centre of mass with another object such as another Neutron Star, a White Dwarf or Black Hole. These systems are a major area of research in physics as they are window into how gravity actually works, as two bodies with intense gravity are coupled together.
Fig 2: A Pulsar-Black Hole Binary
The Binary system orbital period can be extremely short, as little as 90 minutes and the acceleration induced Doppler effect can significantly distort the spectrum making Binary Pulsars extremely difficult to detect.
Up to now pulsar searches have been a slow and laborious as observations are processed off-line using non real time software performing many thousands of trials to correct for the dispersion caused by the interstellar medium not being a true vacuum (for pulsars billions of light years away the delays for different frequencies can be in the region of minutes!), followed by Time-Domain Binary Pulsar search techniques.