2 minute read
Cosmic cartography: mapping the gravitational wave background
from Contact 17
BY DR NORBERT JUNKES (MAX PLANCK INSTITUTE FOR RADIO ASTRONOMY)
An international collaboration of radio astronomers used the MeerKAT Pulsar Timing Array (MPTA) as a galaxy-sized gravitational wave detector by monitoring pulsars to nanosecond precision.
Pulsars spin rapidly, emitting a beam of radio waves with each rotation. The clock-like predictability of their rotations allows astronomers to detect faint deviations from their regular behaviour caused by gravitational waves – minuscule ripples in the fabric of spacetime.
The gravitational waves observed with pulsar timing arrays are caused by some of the Universe’s most powerful sources, from supermassive black hole binaries to events just moments after the Big Bang.
Creating a map of gravitational waves across the sky allows searching for areas with an anomalous excess of gravitational radiation, so-called ‘hot spots’, caused by a single, stand-out supermassive black hole binary, promising insights about the gravitational wave background origin.
Using the largest number of pulsars in any such analysis, and profiting from the high-quality data of the MeerKAT radio telescope, a group of researchers led by Kathrin Grunthal from the Max Planck Institute for Radio Astronomy published the most informative map of the gravitational wave sky so far.
While most parts of the sky did not show notable differences, the research team revealed a small number of intriguing features which will be followed up in future work.
The work by the MPTA collaboration represents a significant leap towards the future of gravitational wave research based on radio astronomy. The results show the crucial role that next-generation radio telescopes, including the SKA telescopes, will play in global efforts to explore the low-frequency gravitational wave Universe.
