A research team led by doctoral candidate FENG Yi and his supervisor Prof. LI Di from National Astronomical Observatories (NAOC) of the Chinese Academy of Sciences and Dr. George Hobbs from The Commonwealth Scientific and Industrial Research Organization (CSIRO) found jitter noise mode in a millisecond pulsar PSR J1022+1001 with the help of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). 

The study was published in The Astrophysical Journal on Feb. 17.

Pulsar timing arrays (PTAs) could be used to detect nanohertz gravitational waves. Understanding noises in the PTA data is crucial for improving timing precision required for detecting nanohertz gravitational waves. 

PSR J1022+1001 has been regularly monitored by PTAs as well as FAST. This represents the initial step of understanding jitter noise of PTA millisecond pulsars with FAST and demonstrates FAST's potential to improve PTA performance.  

Detecting nanohertz gravitational waves using pulsar timing array: gravitational waves sweeping over the pulsar or the Earth introduce fluctuations in pulse times of arrival. (Image by Champion) 

The researchers have recorded ~105 single pulses from PSR J1022+1001 with FAST, and studied their polarization properties, energy distribution, and times of arrival. They analyzed single pulses of PSR J1022+1001 and found jitter noise mode in millisecond pulsars for the first time.

The study demonstrates that FAST can detect individual pulses from pulsars that are observed in order to detect and study gravitational waves. This capability enables detailed studies and parameterization of the noise processes that affect the sensitivity of a pulsar timing array.