Research

Radio monitoring of gravitational wave events

The detection of gravitational waves and electromagnetic radiation from a neutron star merger was a scientific breakthrough, with important implications for physics and astronomy. We are using three Australian radio telescopes to search for and monitor radio waves from future gravitational wave events. These observations will provide key information to unlock the mystery of what causes some of the most energetic events in the Universe, their environment and how they evolve.

Some of our recent papers are:

• Dobie et al. A comprehensive search for the radio counterpart of GW190814 with the Australian Square Kilometre Array Pathfinder
• Dobie et al. Radio afterglows from compact binary coalescences: prospects for next-generation telescopes
• Dobie et al. An ASKAP Search for a Radio Counterpart to the First High-significance Neutron Star-Black Hole Merger LIGO/Virgo S190814bv
• Dobie et al. Constraining properties of neutron star merger outflows with radio observations
• Dobie et al. A turnover in the radio light curve of GW170817
• Mooley et al. A mildly relativistic wide-angle outflow in the neutron-star merger event GW170817
• Hallinan et al. A radio counterpart to a neutron star merger
• Kasliwal et al. Illuminating gravitational waves: A concordant picture of photons from a neutron star merger
• Abbott et al. Multi-messenger Observations of a Binary Neutron Star Merger

ASKAP radio transients

Transients are astronomical objects that appear and disappear or change rapidly; they are our window to some of the most extreme processes in the Universe. Transient events can occur when black holes form, causing supernovae and gamma-ray bursts; when stars collide with black holes; or when hot, magnetised planets interact with their host stars. There are also mysterious transients of unknown origin, like fast radio bursts.

The Variables and Slow Transients (VAST) project on the Australian SKA Pathfinder (ASKAP) telescope will investigate all of these phenomena through a suite of widefield surveys.

Some of our recent papers on gigahertz radio variability are:

• Wang et al. Discovery of PSR J0523-7125 as a Circularly Polarized Variable Radio Source in the Large Magellanic Cloud
• Murphy et al. The ASKAP Variables and Slow Transients (VAST) Pilot Survey
• Wang et al. Discovery of ASKAP J173608.2-321635 as a Highly Polarized Transient Point Source with the Australian SKA Pathfinder
• Leung et al. A search for radio afterglows from gamma-ray bursts with the Australian Square Kilometre Array Pathfinder
• Pritchard et al. A circular polarization survey for radio stars with the Australian SKA Pathfinder
• Wang et al. ASKAP observations of multiple rapid scintillators reveal a degrees-long plasma filament
• Zic et al. A Flare-type IV Burst Event from Proxima Centauri and Implications for Space Weather
• Murphy et al. VAST: An ASKAP Survey for Variables and Slow Transients

ASKAP Radio Telescope from Alex Cherney on Vimeo.

Low frequency radio transients

Magnetised extrasolar planets are expected to emit strongly at low radio frequencies, in the same way that Jupiter does. So far, most exoplanets have been detected through indirect means such as radial velocity and transit searches but radio observations can provide another method of making direct detections.

We are searching for exoplanet emission, and studying other variable sources such as flare stars at low radio frequencies using the Murchison Widefield Array Telescope.

Some of our recent low frequency papers are:

• Lynch et al. The detectability of radio emission from exoplanets
• Murphy et al. Low-Frequency Spectral Energy Distributions of Radio Pulsars Detected with the Murchison Widefield Array
• Murphy et al. A search for long-time-scale, low-frequency radio transients
• Lynch et al. 154 MHz Detection of Faint, Polarized Flares from UV Ceti