An international team of astronomers is planning to use gravitational wave data to unravel the formation processes that created the first supermassive black holes. These gargantuan black holes lurk at the centre of most galaxies, including our own Milky Way, playing a pivotal role in galaxy formation and evolution.
So far astronomers have failed to rally around a single theory to explain the creation process that produces supermassive black holes. Leading theories include the formation of black holes due to the collapse of a first generation of colossal, ancient stars, or possibly a collision between two ancient stellar bodies that formed part of a vast star cluster. Each of these theories would result in the gravitational waves thrown out by the creation event exhibiting a specific mass signature.
A new study led by scientists from Durham University used data from the two confirmed instances of gravitational waves and fed it into a computer simulation known as the EAGLE project, which was supplemented by a simulation designed to calculate gravitational wave signals. EAGLE is in effect an attempt to create a detailed and faithful simulation of the large scale processes at work throughout the greater universe as we currently understand them.
The results suggest that future gravitational wave observatories, such as the proposed Evolved Laser Interferometer Space Antenna (eLISA) mission, will detect the minute ripples in the fabric of spacetime created by violent cosmic events roughly twice a year. eLISA will take the form of three separate spacecraft working in perfect harmony to form a laser interferometer similar to the LIGO instruments responsible for the initial detections of gravitational waves.
The eLISA spacecraft, which are set to launch in 2034, will orbit the Sun in a triangular formation, forming a vast interferometer 250,000 times larger than the detectors on Earth. The technology, a preliminary version of which was recently tested via the LISA Pathfinder mission, will allow for the detection of lower-frequency waves created by the collision of black holes – each of which could be over a million times the mass of the Sun.
By analysing the amplitude and frequency of the waves detected by missions such as eLISA, astronomers could ascertain the initial mass of the seeds of the earliest supermassive black holes which are thought to have formed some 13 billion years ago – relatively soon after the creation of the universe. The existing theory that correlates most accurately with the gravitational wave data would then become the leading origin theory for the creation of supermassive black holes.
Source: University of Durham