My research

Neutron stars are amongst the most fascinating and exotic objects in the Universe and I am interested in all manner of their phenomena.

My research however, focuses on neutron stars as radio pulsars. I am involved in a number of projects ranging from high-precision pulsar timing to prototype software development for next-generation radio telescopes.

A diagram of a radio pulsar

I work with the European Space Agency on the Galileo GNSS mission. We are generating an Earth-independent timescale using data from 18 millisecond radio pulsars observed with the European Pulsar Timing Array (EPTA) as part of a wider effort to detect low frequency gravitational waves from supermassive black-hole binaries. My role is to prepare monthly datasets from the EPTA in order to generate Ensemble Pulsar Time (EPT) . This timescale is then used to steer a physical hydrogen maser clock located at ESA’s ESTEC facility . As part of my role I have developed a software pipeline to collect data from EPTA telescopes, compute the EPT clock signal and continuously monitor data quality.

A Galileo GNSS Satellite

I am also a member of the Square Kilometre Array (SKA) Science Data Processing team where I am developing prototype algorithms for the real-time monitoring of pulsar timing data. I’m particularly interested in the early detection of pulsar glitches for which I am implementing machine learning techniques that can alert astronomers to such events and automatically trigger follow-up observations. These techniques are currently being tested in the Jodrell Bank pulsar timing pipeline.

The Square Kilometre Array

In neutron star science I am primarily interested in the variability of pulsars. In particular, timing and emission variations mediated by changes to the dynamic interiors and magnetic fields of pulsars. To date I have discovered and/or measured ~50 pulsar glitches including the largest ever glitch in the Crab pulsar.


Previously…

I completed my Masters degree in Astrophysics at the University of York. My research there focused on the nuclear physics of accreting neutron stars. These are binary systems in which a neutron star strips material from the envelope of a close evolved companion star. Under the high temperature and pressure conditions of a neutron star surface the material undergoes nuclear burning, getting hotter and hotter, until it explodes as a Type I X-ray burst.

Schematic of the rp-process

During these bursts, unstable proton rich nuclear species are formed in the rapid proton capture (rp- ) process. These decay on a range of timescales towards more stable species. Some species take a relatively long time to decay (e.g., Germanium-64, Selenium-68, Krypton-72) and so the abundances of these nuclei temporarily spike after a burst. These are known as waiting points and their decay rates are not well constrained. We investigated how sensitive the burst output is to the uncertainties in these decay rates and to the composition of the ashes from the previous burst.

I worked as part of the NuGrid collaboration under the supervision of Dr Alison Laird.


Publications

ORCID iD iconorcid.org/0000-0002-9581-2452


Conferences

  • Science Possibilities Investigating Neutron Stars in the UK (SPINS-UK) – UCL, London, UK (2019)
    Talk title: Time-resolved spin-ups in Crab pulsar glitches
  • European Pulsar Timing Array – Bielefeld, Germany (2018)
    Talk title: PulChron – A pulsar timescale demonstration for Galileo
  • Science Possibilities Investigating Neutron Stars (SPINS) – University of East Anglia, UK (2018)
    Talk title: The largest glitch in the Crab pulsar
  • PHAROS WG2 – Superfluids and superconductors in neutron stars – N. Copernicus Astronomical Center, Warsaw, Poland (2018)
    Talk title: The largest glitch in the Crab pulsar
  • LGBT STEMinar – University of York (2018) – Contributing Speaker
    Talk title: Pulsar timing and fundamental physics
  • Pulsar Astrophysics: The Next 50 years. Jodrell Bank (2017) – Contributing Speaker
    Talk title: Correlated emission and spin-variability in pulsars
  • NewCompStar. Southampton, UK (2016) – Invited Speaker
    Talk title: Resolving glitches in the Square Kilometre Array era
  • European Pulsar Timing Array. Cagliari, Sardinia (2016)
  • European Pulsar Timing Array. Orlean, France (2016)
  • International Pulsar Timing Array. New South Wales, Australia (2015)
  • European Pulsar Timing Array. Bonn, Germany (2015)
  • IoP Radioactivity in Astrophysics Meeting. University of York (2014)
  • Nucleosynthesis – Origins and Impacts. Royal Astronomical Society, London (2014)

Press