April 20, 2024

Misbehaving Pulsars: Unexpected Changes in the Most Predictable of Stars

As part of OzGrav, we attempt and discover this gravitational wave background by looking at collections of the most foreseeable stars (called pulsar timing varieties) and determining how they change gradually. We did this by using the worlds most sensitive radio telescopes, consisting of the Australian Murriyang telescope (also called the Parkes telescope) and the ultra-sensitive MeerKAT range telescope in South Africa.
From our observations with MeerKAT we found that the most exactly timed (read: predictable) pulsar, J1909-3744, was misbehaving. We were able to establish a method to account for this change and time tag the pulsar more precisely than ever previously. This technique could be of use for other pulsars and will be crucial when more sophisticated telescopes are readily available in the future.
Composed by OzGrav PhD student Matthew Miles, Swinburne University.

While the majority of pulsars spin around in about a second, there is a subclass of these stars that spin around in just a few thousandths of a second– theyre called millisecond pulsars.
Observing the pulses from these millisecond pulsars provides physicists clues to many questions, including testing General Relativity and comprehending the densest states of matter. These gravitational waves misshape space-time between us and the pulsars, triggering the pulses to show up earlier or later than expected. We were able to establish a method to account for this change and time tag the pulsar more precisely than ever previously.

Artists principle of a pulsar.
Pulsars, a class of neutron stars, are very predictable stars. They are formed from the hearts of massive stars that have actually considering that collapsed in on themselves, no longer able to burn adequate fuel to ward off the squashing gravity the star has. If the conditions are right, the star will continue to collapse in on itself until whats left is a residue of what was there before, typically only about the size of the Melbourne CBD, however 1-2 times as heavy as our Sun, making these a few of the densest objects in deep space.
These stars do not produce much visible light, however from their magnetic poles, they produce surprisingly intense beams of radio waves. If were fortunate, as the star rotates, those beams will wash over the Earth and we observe pulses. While many pulsars spin around in about a second, there is a subclass of these stars that spin around in just a few thousandths of a second– theyre called millisecond pulsars.
Observing the pulses from these millisecond pulsars provides physicists ideas to lots of concerns, including screening General Relativity and understanding the densest states of matter. These gravitational waves misshape space-time in between us and the pulsars, causing the pulses to get here earlier or later than anticipated.