Image of the night sky

GOTO will scour the skies for optical clues about the violent cosmic events that create ripples in the fabric of space itself

21 July 2022

4 min read

A new telescope, made up of two identical systems on opposite sides of the planet, will track down sources of gravitational waves.

The Gravitational-wave Optical Transient Observer (GOTO), which involves cosmologists from the University of Portsmouth, will help shepherd in a new era of gravitational wave science.

Deployed across two locations (in La Palma, in Spain’s Canary Islands and Australia’s Siding Spring Observatory) to fully cover the sky, GOTO will scour the skies for optical clues about the violent cosmic events that create ripples in the fabric of space itself.

The two telescope mount systems, each made up of eight individual 40 cm (16 inch) telescopes, cover a very large field of view with 800 million pixels across their digital sensors, enabling them to sweep the visible sky every few nights. These robotic systems will operate autonomously, patrolling the sky continuously but also focusing on particular events or regions of sky in response to alerts of potential gravitational wave events.

It is exciting to be involved in this developing project with GOTO, particularly given the ICG’s outstanding experience in citizen science, gravitational-waves, and transient astronomy.

Dr Lisa Kelsey, Institute of Cosmology and Gravitation

GOTO began when the UK’s University of Warwick and Australia’s Monash University wanted to address the gap between gravitational wave detectors and electromagnetic signals. Now the international collaboration has 10 partners, six of which are in the UK, including the University of Portsmouth.

It has received £3.2 million of funding from the Science and Technology Facilities Council (STFC) to deploy the full-scale facility.

GOTO will also give members of the public the exciting opportunity to get involved with this science. Led by Dr Lisa Kelsey, from the University of Portsmouth’s Institute of Cosmology and Gravitation (ICG), GOTOZoo will allow members of the public to participate in searching for gravitational-waves, aiding researchers in determining real signals of optical counterparts in GOTO images. By “spotting the difference” between sets of images, citizen scientists will discover new optical signals and help train machine-learning algorithms to detect such signals in the vast amount of data GOTO will obtain.

Alongside Dr Kelsey, the ICG GOTO team consists of Dr Laura Nuttall, Dr Or Graur and Dr Peter Clark.

Dr Kelsey said: “Citizen science is a particularly valuable tool, not only does it engage the public with innovative science in a fun and dynamic way, the work of the citizen scientists on GOTOZoo will be used to make real scientific progress. It is exciting to be involved with this developing project with GOTO, particularly given the ICG’s outstanding experience in citizen science, gravitational-waves, and transient astronomy.”

The two telescope mount systems will sweep the visible sky every few nights. Credit: University of Warwick

Long hypothesised as a by-product of the collision and merger of cosmic behemoths such as neutron stars and black holes, gravitational waves were finally detected directly by the Advanced LIGO (Laser Interferometry Gravitational-wave Observatory) in 2015.

Since 2015, there have been many subsequent detections but, since observatories like LIGO can only measure the effects of the gravitational wave as it passes through our local patch of space time, it can be difficult to track down the source’s point of origin.

GOTO is designed to fill this observational gap by searching for optical signals in the electromagnetic spectrum that might indicate the source of the gravitational wave – quickly locating the source and using that information to direct a fleet of telescopes, satellites and instruments at it.

Citizen science is a particularly valuable tool, not only does it engage the public with innovative science in a fun and dynamic way, the work of the citizen scientists on GOTOZoo will be used to make real scientific progress.

Dr Lisa Kelsey, Institute of Cosmology and Gravitation

The idea is that GOTO will act as sort of go between the likes of LIGO, which detect the presence of a gravitational wave event, and more targetable multi-wavelength observatories that can study the event’s optical source.

The optical search for gravitational wave events is the next step in the evolution of gravitational wave astronomy. It has been achieved once before, but with GOTO’s help it should become much easier.

If astronomers can locate convincing counterparts to gravitational wave signals, it will be possible to measure distances, characterise the sources, study their evolution and determine the environments they are formed in.