Research

Pulsar Timing Array

Pulsars are rapidly rotating neutron stars and are the most precise clocks in the Universe. When a gravitational wave passes a Pulsar Timing Array (PTA), the arrival time of the pulses on Earth is affected by a tiny amount of less than 100 nanoseconds. The largest telescopes on Earth are used to precisely monitor the rotating ticks of these pulsars over decades to reveal the faint echoes of distant black holes.

See the following for details: EPTA press release, MPIfR press release

A cosmic population of binary supermassive black holes generates a background of gravitational waves.

Related proposals:

PI Effelsberg telescope, Key Science Project: Pulsar Timing for the European Pulsar Timing Array (65-19), 1992 hr, 2019-2022

Co-I Effelsberg telescope, Pulsar Timing for the European Pulsar Timing Array: a Key Science Project (73-22), 2200 hr, 2022-2025

Co-I FAST telescope, Über-LEAP – the most powerful pulsar telescope, 5 hr, 2019

Co-I Effelsberg telescope, Understanding the scattering geometry of PTA pulsars (72-19, 89-19), 35 hr, 2019

Testing Gravity with binary pulsars

Since the discovery of PSR B1913+16 by Russell Hulse and Joseph Taylor, binary pulsars opened a new arena for testing gravity in the quasi-stationary and radiative regimes (first evidence of gravitational waves!). Currently, the best laboratory for gravity tests is the Double Pulsar system, PSR J0737-3039A/B, discovered by Marta Burgay in 2003. This unique system provides a wide range of gravity tests more than in any other pulsar systems, including the most precise measurement of quadrupolar gravitational waves, orbital precession, time dilation (second-order Doppler effect and gravitational redshift), Shapiro delay and higher-order signal propagation effects, spin precession, and relativistic deformation of the orbit (see Kramer et al. 2021). With the superior precision of the MeerKAT telescope, we are now improving these tests and probing new higher-order effects (see Hu et al. 2022).

Artistic illustration of the Double Pulsar system, where two active pulsars orbit each other in just 147 min.

Related proposals:

PI MeerKAT telescope, Testing higher order GR effects with the Double Pulsar (MeerTIME), 180 hr, 2019-2024

Co-I Parkes telescope, Timing & geodetic precession in the double pulsar (P455), 2019-2023

Co-I uGMRT telescope, Monitoring Double Pulsar at low frequencies with the upgraded GMRT, 2021-2023

Co-I FAST telescope, Testing the Theories of Gravitation with Pulsars, 2021-2023