Gravitational wave detectors resume their observation

May 24. (EUROPE PRESS) –

The LIGO-Virgo-KAGRA (LVK) collaboration A new round of gravitational wave observation with improved instruments, signal models and analysis methods has begun on May 24.

LVK is made up of scientists from around the world who use a network of observatories (LIGO in the United States, Virgo in Europe, and KAGRA in Japan) to search for gravitational waves, or ripples in space-time, generated by the collision of black holes and other extreme cosmic events.

This observing run, known as O4, promises to take gravitational wave astronomy to the next level, according to an institutional statement. O4 will start on May 24 and run for 20 months, including up to two months of start-up breaks. It will be the most sensitive search yet for gravitational waves. LIGO will resume operations on May 24, while Virgo will join later in the year. KAGRA will join for a month, starting May 24, and will be reintroduced later after a few updates.

With the increased sensitivity of the detectors, O4 will observe a larger fraction of the universe than previous observing runs. LIGO detectors will start with O4 approximately 30% more sensitive than before. This increased sensitivity will result in a higher rate of observed gravitational wave signals, resulting in the detection of a merger every 2-3 days.

Furthermore, the increased sensitivity will increase the ability to extract more physical information (including unique astrophysical and cosmological information) from the data. This higher signal fidelity will improve scientists’ ability to test Einstein’s theory of general relativity and infer the true population of dead stars in the local Universe.

The first gravitational wave signals were detected in 2015. Two years later, LIGO and Virgo detected a merger of two neutron stars, triggering an explosion called a kilonova, subsequently observed by dozens of telescopes around the world. So far, the global network has detected more than 80 black hole mergers, two likely neutron star mergers, and some events that were likely black hole-neutron star mergers. During O4, the researchers hope to observe even more energetic cosmic events and gain new insights into the nature of the universe.

As in previous observing periods, alerts on gravitational wave detection candidates will be publicly distributed during O4.

The Virgo Collaboration is currently composed of approximately 850 members from 143 institutions in 15 different countries (mainly European).