The new BlackGEM telescopic array at the European Southern Observatory’s (ESO’s) La Silla Observatory in Chile has officially begun scanning the southern skies, searching for the sources of gravitational waves.
Gravitational waves are ripples in space-time caused by violent, energetic space phenomena, such as colliding black holes or neutron stars, or massive stars exploding as supernovae at the end of their lives.
Existing observatories like the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo Interferometer are specially designed to detect the ripples caused by gravitational waves. Interferometers merge two or more light sources to create an interference pattern, which can be measured and analyzed. However, LIGO and Virgo can’t pinpoint the exact origin of gravitational waves or see the light emanating from colliding neutron stars or black holes.
That’s where BlackGEM is different. It can detect both gravitational waves and visible light from these events and use the information to determine the precise location of the wave source. Using visible light also means BlackGEM can obtain detailed observations of processes such as the formation of heavy elements like gold and platinum from these interstellar collisions.
“With BlackGEM, we aim to scale up the study of cosmic events with both gravitational waves and visible light," said Paul Groot of Radboud University in the Netherlands and the project’s principal investigator. “The combination of the two tells us much more about these events than just one or the other.”
The BlackGEM array comprises three telescopes built by Radboud University, the Netherlands Research School for Astronomy, and KU Leuven in Belgium. Each telescope is 25.6 in (65 cm) in diameter and can simultaneously scan different parts of the sky. There are plans to expand the array to 15 telescopes.
They may be relatively small, but these telescopes can observe much, thanks to their location. They sit at an altitude of 1.5 mi (2.4 km) on the outskirts of the Chilean Atacama Desert.
“Despite the modest 65-centimeter (26-in) primary mirror, we go as deep as some projects with much bigger mirrors, because we take full advantage of the excellent observing conditions at La Silla,” Groot said.
Once BlackGEM identifies the source of a gravitational wave, the information will be sent to larger telescopes like ESO’s Very Large Telescope, also located in the Atacama Desert, which can undertake more detailed follow-up observations.
In addition to searching for the sources of gravitational waves, BlackGEM will keep an eye out for short-lived astronomical events such as supernovae.
“Thanks to BlackGEM, La Silla now has the potential to become a major contributor to transient research,” said Ivo Saviane, site manager at the La Silla Observatory. “We expect to see many outstanding results contributed by this project, which will expand the reach of the site for both the scientific community and the public at large.”
The below video, produced by ESO, shows footage of the BlackGEM array at the La Silla Observatory in Chile’s Atacama Desert.
Source: European Southern Observatory
