These beams were analysed by Professor John Losecco, revealing variations and delays that suggest the presence of an invisible mass, possibly dark matter. LoSecco used data from the PPTA2 survey, including precise measurements from several radio telescopes. The study found about a dozen cases where dark matter is likely to be affecting pulsar signals. This research not only helps with understanding dark matter, but also improves the timing of pulsars for other astronomical studies.

Detecting dark matter using pulsars

Startling evidence of potential dark matter objects has been discovered with the help of the universe’s “timekeepers.” These pulsars, spinning neutron stars that emit beacon-like beams of radio waves that race through space, have been used to identify mysterious, hidden masses.

Pulsars get their nickname because they send out electromagnetic radiation at regular intervals from milliseconds to seconds, making them extremely precise timekeepers.

“Science has developed very precise methods for measuring time,” said the astronomer behind the study, Professor John Losecco of the University of Notre Dame, who recently presented his findings at the National Astronomy Meeting at the University of Hull.

“We have an atomic clock on Earth, and we have pulsars in space. “Although it has been known for over a century that gravity slows down light, its applications have been few until now.”

Observation of pulsar time changes

Professor LoSecco observed changes and delays in the timing of pulsars, indicating that the radio beams are moving around an invisible concentration of mass somewhere between the pulsar and the telescope.

He believes these invisible masses are candidates for dark matter objects.

Professor LoSecco studied the delays in the arrival time of radio pulses, which are usually accurate to nanoseconds. He investigated the trajectory of radio pulses in the PPTA2 survey data released from the Parkes Pulsar Time Array.

This ongoing project provides precise measurements of pulse arrival times using data from seven different radio telescopes: Effelsberg, Nansai, Westerbork, Greenbank, Arecibo, Parkes and Lovell, the latter in Cheshire. The pulses have a frequency of approximately three weeks across the three observation intervals.

Change in arrival times due to dark matter

Arrival time deviations due to dark matter have a well-defined shape and size proportional to its mass. Light passing near regions of dark matter will be slowed down by its presence. A search for precise data from 65 “millisecond pulsars” has revealed about a dozen events that appear to interact with dark matter.

Professor Losecco said: “We use the fact that the Earth moves, the Sun moves, the pulsar moves and even the dark matter moves.

“We observe deviations in arrival times caused by changes in the distance between the observed mass and the line of sight of our ‘clock’ pulsar.”

A mass the size of the Sun would cause a delay of about 10 microseconds. The resolution of the observations made by Professor LoSecco is on the order of nanoseconds, 10,000 times smaller.

“One of the findings suggests a decay of about 20 percent of the mass of the Sun,” said Professor Losecco. “This object could be a dark matter candidate.”

Pulsar sync data sampling improvements

He also confirmed that a side effect of this work was to improve the sampling of pulsar timing data. This precise sample was collected to look for evidence of low-frequency gravitational radiation.

Dark matter objects add “noise” to these data, so identifying and removing them would clean up some instances of variability by removing such noise in other gravitational radiation surveys.

Shedding light on dark matter

“The true nature of dark matter is a mystery,” said Professor Losecco. “This work sheds new light on the nature of dark matter and its distribution in the Milky Way, and could improve the precision of pulsar data.”