Pulsars are some of the most extreme objects in our cosmic backyard, forming from dying stars that have collapsed to form neutron stars that can fit within any county in Ireland. This multiple orders-of-magnitude change in scale results in the same effect as an ice skater bringing their arms in, resulting in them spinning in an extremely stable manner, often at significant fractions of the speed of light. At the moment, the fastest known pulsar can perform a rotation in under 2ms, while the slowest rotates only once every 23 seconds. With such extreme masses, rotation velocities and companion stars often sharing their star system, they are the perfect laboratories for some of our most extreme theories, such as general relativity or gravitational waves.
Given they only emit light in the direction of Earth for a fraction of their rotation, I-LOFAR sees pulsars as sudden flashes of light, at an extremely regular cadence. As a result of their incredibly stable nature, combining information on the arrival time of each flash of light can allow us to get extremely precise measurements of the properties of a pulsar. For example, pulsar J1738+0333 has a rotation period known to within two attoseconds (that’s 0.000000000000000002 seconds!).
I-LOFAR is also surveying a subclass of pulsars known as rotating radio transients (RRATs). Unlike most pulsars, these sources are more akin to a lighthouse that needs a bulb replaced, as they may only spark to life once or twice an hour, or at even rarer cadences in some cases. Though since the neutron star itself is still spinning, there is still a wealth of information that can be collected on these sources from the rare occasion that they are visible in the sky.