LOS ANGELES, April 1 (Xinhua) -- The U.S. Laser Interferometer Gravitational-Wave Observatory (LIGO) resumed its hunt for gravitational waves on Monday, after receiving a series of upgrades to its lasers, mirrors and other components.
LIGO now has a combined increase in sensitivity of about 40 percent over its last run. This means that it can survey an even larger volume of space than before for powerful, wave-making events, such as the collisions of black holes, according to the LIGO lab at the California Institute of Technology (Caltech).
Joining the search will be Virgo, the European-based gravitational-wave detector, which has almost doubled its sensitivity since its last run and is also starting up April 1.
"With LIGO and Virgo observing together for the next year, we will surely detect many more gravitational waves from the types of sources we've seen so far. We're eager to see new events too, such as a merger of a black hole and a neutron star," said Peter Fritschel, LIGO's chief detector scientist at the Massachusetts Institute of Technology.
In 2015, LIGO made history by making the first direct detection of gravitational waves. The ripples traveled to the Earth from a pair of colliding black holes located 1.3 billion light-years away.
Since then, the LIGO-Virgo detector network has uncovered nine additional black hole mergers and one explosive smashup of two neutron stars.
Now, with the start of the next joint LIGO-Virgo run, the observatories are poised to detect an even greater number of black hole mergers and other extreme events, such as additional neutron-neutron star mergers or a yet-to-be-seen black hole-neutron star mergers.
"The LIGO team has spent months commissioning all of these new systems, making sure everything is aligned and working correctly," said Calum Torrie, LIGO's mechanical-optical engineering head at Caltech.
He said all of the upgrades mean that LIGO can now see farther into space to find the most extreme events in the universe.
