Pulsar Science with the SKA Observatory

The large instantaneous sensitivity, a wide frequency coverage and flexible observation modes with large number of beams in the sky are the main features of the SKA observatory’s two telescopes, the SKA-Low and the SKA-Mid, which are located on two different continents. Owing to these capabilities, the SKAO telescopes are going to be a game-changer for radio astronomy in general and pulsar astronomy in particular. The eleven articles in this special issue on pulsar science with the SKA Observatory describe its impact on different areas of pulsar science. In this lead article, a brief description of the two telescopes highlighting the relevant features for pulsar science is presented followed by an overview of each accompanying article, exploring the inter-relationship between different pulsar science use cases.

💡 Research Summary

The paper serves as the introductory overview for a special issue on pulsar science with the Square Kilometre Array Observatory (SKAO). It outlines the two SKA facilities—SKA‑Low in Western Australia and SKA‑Mid in South Africa—detailing their design, frequency coverage (50 MHz–15 GHz), and phased‑array configurations (AA* and the later AA4). SKA‑Low will consist of 307–512 stations, each equivalent to a 39 m dish, with a dense core of up to 224 stations that can form multiple independently steerable tied‑array beams. SKA‑Mid will comprise 144–197 dishes (including the existing MeerKAT 13.5 m antennas) arranged in a similar core‑plus‑spiral layout, covering five bands, of which Bands 1 (350–1050 MHz) and 2 (950–1760 MHz) are most relevant for pulsar work.

Two key non‑imaging subsystems are described: the Pulsar Timing Subsystem (PST) and the Pulsar Search Subsystem (PSS). PST will process up to 16 wide‑band tied‑array beams (300 MHz for SKA‑Low, up to 2.5 GHz for SKA‑Mid) and deliver calibrated voltage time series, PSRFITS filterbanks, and integrated pulse profiles. PSS will conduct near‑real‑time searches on up to 1500 beams (AA4) with bandwidths of 100–300 MHz, supporting long integrations, acceleration searches, and single‑pulse detection pipelines. Some capabilities—such as a reduced number of core stations for SKA‑Low and fewer PSS beams in the early AA* stage—have been deferred but are slated for later restoration.

The scientific impact is framed around three major goals. First, a comprehensive pulsar census: the combined SKA‑Low/‑Mid surveys are expected to double the known pulsar population, discovering roughly 10 000–12 000 pulsars (including ~800–1 200 millisecond pulsars) by the AA4 stage. Second, targeted studies of dense environments: deep SKA‑Mid searches will dramatically increase the number of pulsars in globular clusters (potentially up to ~1 700) and, with high‑frequency capability, will finally uncover pulsars in the immediate vicinity of the Galactic Centre black hole. Third, fundamental physics: the enlarged, precisely timed sample will enable stringent tests of neutron‑star equations of state, nano‑Hertz gravitational‑wave backgrounds via pulsar timing arrays, and relativistic gravity in extreme binaries.

Overall, the paper emphasizes that the unprecedented sensitivity, wide frequency range, and flexible multi‑beam operation of SKA‑Low and SKA‑Mid will transform pulsar astronomy, providing the foundation for a new era of high‑precision astrophysics and fundamental‑physics experiments.