'Black hole police' discovered a dormant black hole outside our galaxy

BY
TECH EXPLORIST
JULY 18, 2022 21:25 IST



This artist’s impression shows what the binary system VFTS 243 might look like if we were
observing it up close. The system, which is located in the Tarantula Nebula in the Large Magellanic
Cloud, is composed of a hot, blue star with 25 times the Sun’s mass and a black hole, which is at
least nine times the mass of the Sun. The sizes of the two binary components are not to scale: in
reality, the blue star is about 200 000 times larger than the black hole. Note that the 'lensing' effect
around the black hole is shown for illustration purposes only, to make this dark object more
noticeable in the image. The inclination of the system means that, when looking at it from Earth,
we cannot observe the black hole eclipsing the star. Credit: ESO/L. Calçada


A team of international experts renowned for debunking several black hole discoveries, have found a stellar-mass black hole in the Large Magellanic Cloud, a neighbour galaxy to our own. “For the first time, our team got together to report on a black hole discovery, instead of rejecting one,” says study leader Tomer Shenar. Moreover, they found that the star that gave rise to the black hole vanished without any sign of a powerful explosion. The discovery was made thanks to six years of observations obtained with the European Southern Observatory’s (ESO’s) Very Large Telescope (VLT).

“We identified a ‘needle in a haystack’,” says Shenar who started the study at KU Leuven in Belgium and is now a Marie-Curie Fellow at Amsterdam University, the Netherlands. Though other similar black hole candidates have been proposed, the team claims this is the first ‘dormant’ stellar-mass black hole to be unambiguously detected outside our galaxy.

Stellar-mass black holes are formed when massive stars reach the end of their lives and collapse under their own gravity. In a binary, a system of two stars revolving around each other, this process leaves behind a black hole in orbit with a luminous companion star. The black hole is ‘dormant’ if it does not emit high levels of X-ray radiation, which is how such black holes are typically detected.

“It is incredible that we hardly know of any dormant black holes, given how common astronomers believe them to be,” explains co-author Pablo Marchant of KU Leuven. The newly found black hole is at least nine times the mass of our Sun, and orbits a hot, blue star weighing 25 times the Sun’s mass.

More:
https://www.techexplorist.com/black-hole-police-discovered-dormant-black-hole-outside-galaxy/52555/