Colossus hidden in the universe, this black hole is one of the most huge ever detected!
Cosmic horseshoe is actually made up of two galaxies. © NASA/ESA/Hubble
Cosmic horseshoe (Cosmic Horseshoe in English) is made up of two galaxies that appear to us in each other and are far from us. The closest is around 5 billion light years. The most distant, that which forms the arc of circle, is more than 18 billion light years! This strange galactic ensemble is in the direction of the Lion Constellation and was discovered in 2007.
A magnificent Einstein ring at 18 billion light years
This form of horseshoe is obtained by a so -called gravitational lens effect. In reality, the ring -shaped galaxy is three times further than that which is in the center, its light being deflected and amplified by the gigantic mass of the latter before reaching us (you will find A very educational article on the explanation of gravitational lenses). This phenomenon is also called a “Einstein ring”.
Diagram of a gravitational lens. © Wikipedia
The galaxy responsible for such a deformation, in the center of the cosmic horseshoe and baptized very little poetically LRG 3-757, belongs to a very rare category of super-heavy weight of the universe. It is an LRG (red light galaxy) whose mass approaches 100 times that of the Milky Way!
One of the biggest black holes in the whole universe
M87*, a supermassive black hole of 6 billion solar masses. © EHT
In such a galaxy, astronomers expect the presence of a central black hole of an extraordinary mass, much higher than that of Sagittarius has* in the heart of the Milky Way (4 million solar masses). And here they were not disappointed, that Nenni! This cosmic ogre is even in the top 10 of the most massive ever spotted by our telescopes. It “weighs” about 35 billion solar masses and displays about 100 billion kilometers of radius… It is no longer even a black hole called supermassive, but ultramassive.
To detect such an astrophysical object so far, astronomers used the speed of stars in the bulb of the galaxy. The more the stars move there and in a chaotic way, the greater the mass of the central object. It is this “speed dispersion” tool, associated with Kepler lawswhich made it possible to infer a mass at this black hole.
The European mission Euclid From ESA, which is underway, should spot other Einstein rings like this, so helping to better understand the presence of black holes as huge and so far/early in the universe.
