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Parkes Pulsar Timing Array


parkes telescope

The Parkes Pulsar Timing Array (PPTA) project is a combined effort from astronomers and students across several institutions dedicated to the very first detection of gravitational waves in the pulsar timing band.

The PPTA project was formed in 2004 as a collaboration between CSIRO Astronomy and Space Science and Swinburne University of Technology, and welcomes members from across the globe. The PPTA is now a member of the International Pulsar Timing Array, a global consortium sharing the common goal.

The 64 metre Parkes Radio Telescope located in Parkes, New South Wales, Australia, is the key instrument in this project, collecting data over many years from an array of fast-spinning stars in our Milky Way Galaxy emitting beams of radio waves, called millisecond pulsars (MSPs).

Latest news

MATLAB code for Zhu et al. 2016 (MNRAS, 461, 1317) is available from here.

Our publications for 2015 include:

Parkes observations are now all conducted remotely. We are observing from the Marsfield SOC, our home universities, the comfort of our own homes, and one of us even observed on a transpacific flight once!

Publically available PPTA data sets

The following PPTA-related data sets are available for public download:

  • PPTA pulse profiles: Pulse profiles processed using Parkes Pulsar Timing Array data. The results are high signal-to-noise ratio profiles for 24 millisecond pulsars (in three observing bands). The work and scientific results are published in Dai et al. (2015).
  • PPTA pulsar data set from Reardon et al. (2015): Processing of the Parkes Pulsar Timing Array data set as published by Reardon et al. (2015). The collection contains pulsar timing models, arrival times and noise models.
  • The Parkes Pulsar Timing Array (PPTA) Data Release 1: This collection contains data from the Parkes Pulsar Timing Array (PPTA) project and was published in Manchester et al. (2013) as our first data release.
  • Madison et al. data set for gravitational wave search: This collection contains the data sets produced for Madison et al. This paper describes versatile directional searches for gravitational waves with pulsar timing arrays and makes use of actual Parkes Pulsar Timing Array (PPTA) data and also simulated data sets.

The PPTA project in brief

The PPTA project aims to fulfill the following goals:

  • Detection of gravitational waves
Gravitational waves were predicted by Albert Einstein in 1916, as part of his 'General Theory of Relativity'. He postulated that accelerating massive bodies would create ripples in space and time, stretching and shrinking anything in their path. However the effect is miniscule, for example a wave passing through a dining table would change its length by about the width of a proton!. It is clear that very high precision measurements would be needed in order to detect any such effect. This is where MSPs come in. These stars emit pulses of radio waves in a predictable clock-like fashion, akin to a lighthouse. Astronomers at Parkes can measure the arrival time of these pulses from an array of MSPs dotted around the sky with very high precision, and compare that with the predicted arrival time gained by long-term monitoring of these pulsars. It is thought that if a gravitational wave created by two super-massive black holes about to merge (the most massive objects in the Universe that we know of) were to pass by, it would stretch and shrink the pulses of radio waves in such a way that all the pulsars in the array would show a correlated change in pulse arrival time.
  • Develop a pulsar-based time standard
Long-term monitoring of the PPTA pulsars has lead to development of the first pulsar-based timescale with a precision comparable to that of terrestrial timescales. Please see Development of a pulsar-based timescale for more information.
  • Search for unknown objects in the Solar System
An offshoot of high precision pulsar timing is the ability to locate masses in our Solar System. The PPTA team have attempted to improve the estimates of masses of planets in our Solar system and have derived the most precise published estimate of the mass of the Jovian system. Please see Measuring the mass of solar system planets using pulsar timing for more information.
  • Expand knowledge of other astrophysical phenomena
PPTA data sets provide information not only on arrival times, but the nature of the intrinsic source itself such as pulse variability and timing irregularities. In addition, we can learn about the nature of the interstellar medium (ISM) along the line of sight to the source, and interaction with the Solar wind.

For a more extensive overview of the PPTA project, please see The Parkes Pulsar Timing Array: What we've done and what we're doing, and in more detail including the first PPTA data release in The Parkes Pulsar Timing Array Project.

How to get involved

The PPTA project welcomes new members to help contribute to this fascinating and expanding area of research.

If you wish to become a member, or are a student who would like to get involved in the research, please contact the team leader George Hobbs, for more information.

Learn more

If you are interested in learning more about the general principles behind pulsar astronomy, pulsar timing and gravitational waves, please go to our Education & Outreach page.

All PPTA team members may update this page. However, please contact Lawrence Toomey if you feel that major changes are required.