Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

The international pulsar timing array project: using pulsars as a gravitational wave detector

G. Hobbs, A. Archibald, Z. Arzoumanian, D. Backer, M. Bailes, N. D. R. Bhat, M. Burgay, S. Burke-Spolaor, D. Champion, I. Cognard, W. Coles, J. Cordes, P. Demorest, G. Desvignes, R. D. Ferdman, L. Finn, P. Freire, M. Gonzalez, J. Hessels, A. Hotan, G. Janssen, F. Jenet, A. Jessner, C. Jordan, V. Kaspi, M. Kramer, V. Kondratiev, J. Lazio, K. Lazaridis, K. J. Lee, Y. Levin, A. Lommen, D. Lorimer, R. Lynch, A. Lyne, R. Manchester, M. McLaughlin, D. Nice, S. Oslowski, M. Pilia, A. Possenti, M. Purver, S. Ransom, J. Reynolds, S. Sanidas, J. Sarkissian, A. Sesana, R. Shannon, X. Siemens, I. Stairs, B. Stappers, D. Stinebring, G. Theureau, R. van Haasteren, W. van Straten, J. P. W. Verbiest, D. R. B. Yardley, X. P. You

TL;DR

This paper outlines the International Pulsar Timing Array (IPTA) approach to detecting ultra-low-frequency gravitational waves by combining pulsar timing data from a worldwide network. It explains how gravitational waves produce correlated timing residuals across many millisecond pulsars, enabling discrimination from systematics via the Hellings-Downs signature, and discusses SMBH-binary-driven stochastic backgrounds as the main target. The authors review current observational limits, the status of IPTA as a collaboration, and the expected gains from upcoming facilities (LEAP, SKA, FAST) that will dramatically improve timing precision and pulsar counts. They project detections within 5–10 years, with the SKA-era yielding detailed background measurements and potential individual source detections, thereby inaugurating GW astronomy with pulsars.

Abstract

The International Pulsar Timing Array project combines observations of pulsars from both Northern and Southern hemisphere observatories with the main aim of detecting ultra-low frequency (~10^-9 to 10^-8 Hz) gravitational waves. Here we introduce the project, review the methods used to search for gravitational waves emitted from coalescing supermassive binary black-hole systems in the centres of merging galaxies and discuss the status of the project.

The international pulsar timing array project: using pulsars as a gravitational wave detector

TL;DR

This paper outlines the International Pulsar Timing Array (IPTA) approach to detecting ultra-low-frequency gravitational waves by combining pulsar timing data from a worldwide network. It explains how gravitational waves produce correlated timing residuals across many millisecond pulsars, enabling discrimination from systematics via the Hellings-Downs signature, and discusses SMBH-binary-driven stochastic backgrounds as the main target. The authors review current observational limits, the status of IPTA as a collaboration, and the expected gains from upcoming facilities (LEAP, SKA, FAST) that will dramatically improve timing precision and pulsar counts. They project detections within 5–10 years, with the SKA-era yielding detailed background measurements and potential individual source detections, thereby inaugurating GW astronomy with pulsars.

Abstract

The International Pulsar Timing Array project combines observations of pulsars from both Northern and Southern hemisphere observatories with the main aim of detecting ultra-low frequency (~10^-9 to 10^-8 Hz) gravitational waves. Here we introduce the project, review the methods used to search for gravitational waves emitted from coalescing supermassive binary black-hole systems in the centres of merging galaxies and discuss the status of the project.

Paper Structure

This paper contains 8 sections, 2 equations, 4 figures, 1 table.

Table of Contents

  1. Introduction
  2. Induced timing residuals caused by gravitational waves
  3. Expected sources of gravitational waves
  4. Status of the IPTA project
  5. Future data sets
  6. Outreach
  7. Conclusion
  8. Acknowledgements

Figures (4)

  • Figure 1: The expected correlation in the timing residuals of pairs of pulsars as a function of angular separation for an isotropic GW background.
  • Figure 2: Simulation of the induced timing residuals for PSR B1855$+$09 caused by a postulated supermassive binary black hole system in the radio galaxy 3C66B.
  • Figure 3: Detection significance of a GW background with given amplitude for data spanning five years for different pulsar timing arrays. Also shown is the expected detection significance for the IPTA project after 10 years. The detection significance is defined in the appendix of Verbiest et al. (2009).
  • Figure 4: The sensitivity to individual sources of GWs is shown for the IPTA and a possible future experiment with the SKA. The expected signals from coalescing black holes at the cores of 3C66B and OJ287 are shown. The dashed lines indicate the expected signals from black hole binary systems with chirp masses of $10^9$ and $10^{10}$ M$_\odot$ respectively, situated in the Virgo cluster. For comparison, sensitivity curves of LIGO and LISA and predicted signal levels are also shown.