Space-time ripples flip our understanding of black holes & neutron stars upside down
28 June, 2020, 13:09
With the help of Caltech's Zwicky Transient Facility (ZTF), funded by the National Science Foundation (NSF) and located at Palomar Observatory near San Diego, the scientists have spotted what might be a flare of light from a pair of coalescing black holes.
An global research collaboration has detected a mystery object inside the puzzling area known as the "mass gap" - the range that lies between the heaviest known neutron star and the lightest known black hole, according to a new study published on Tuesday. GW190814 is highlighted in the middle of the graphic as the merger of a black hole and a mystery object around 2.6 times the mass of the sun. The process of merging gave the object a kick that should cause it to enter the supermassive black hole's disk again, producing another flash of light that ZTF should be able to see.
"It is the reaction of the gas to this speeding bullet that creates a bright flare, visible with telescopes", said Barry McKernan, who is a co-author of the study.
"GW190814 is an unexpected and a really exciting discovery", said in a statement Abhirup Ghosh, a post-doctoral researcher in the Astrophysical and Cosmological Relativity division at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Potsdam.
A mysterious object roughly 800 light years from Earth detected using gravitational wave sensors is either one of the smallest black holes or one of the largest neutron stars so far discovered, scientists said on Wednesday.
Originally published June 23, 2020 by the worldwide LIGO-Virgo collaboration.
Telltale ripples in the fabric of spacetime have revealed the existence of a cosmic object that scientists can't definitively classify.
Black holes are as notoriously hard to spot as their name would suggest. "We don't know if this object is the heaviest known neutron star, or the lightest known black hole, but either way it breaks a record".
The worldwide group, which has strong United Kingdom involvement backed by the Science and Technologies Facilities Council, has laser detectors several kilometres long that are able to detect minute ripples in space-time caused by the collision of massive objects in the Universe. If a neutron star was involved in last August's crash, there might have been a similar flash. But it was also lighter than the lightest black hole previously observed - of around five solar masses.
That places it in the Universe's "mass gap", referring to the virtually complete lack of observed objects between 2.6-5 solar masses. But Prof Fairhurst's colleague, Prof Fabio Antonioni, has proposed that a solar system with three stars could lead to the formation of light black holes.
If the starting star is below a certain mass, one option is for it to collapse into a dense ball composed entirely of particles called neutrons, which are found inside the heart of atoms.
But as the astrophysicists ran more analyses on the data, they realised they were looking at something even stranger.
The material from which neutron stars are composed is so tightly packed that one teaspoonful would weigh 10 million tonnes. At the same time in the Universe was discovered a new kind of black hole.
"We don't know how the nuclear strong force operates under the extreme conditions you need inside a neutron star".
Prof Sheila Rowan, director of the University of Glasgow's Institute for Gravitational Research (IGR), said the discovery challenges current theoretical models. "So, every single current theory we now have of what goes on inside of one has some uncertainty". In any case, the astronomers had never seen such objects, which greatly puzzled them.