Astronomers have made a sensational discovery: one of the most massive black holes known to science is hiding at the center of the gravitational lens “Cosmic Horseshoe”.
The study has shown that the galaxy LRG 3-757, located 5.5 billion light years from Earth, contains an ultramassive black hole (UMBH) with a colossal mass of 36 billion solar masses. The “Cosmic Horseshoe” is a gravitational lens – a phenomenon in which a massive galaxy bends and amplifies the light of a distant background, creating a characteristic Einstein ring. LRG 3-757, which acts as a lens, belongs to the category of bright red galaxies (LRG) and is itself one of the most massive known to science: its mass is about 100 times greater than the Milky Way. The new study not only confirmed the existence of a giant black hole at its center, but also revealed that it does not fit into standard models of galaxy evolution.
The scientists checked whether the mass of this black hole corresponds to the relationship between the mass of supermassive black holes and the velocities of stars in the central part of the galaxy. The more massive the black hole, the faster the stars in its vicinity should move. However, the UMBH in LRG 3–757 deviates from this relationship: its mass is too large for the given speed of stellar motion. This indicates that the evolution of such massive galaxies could have followed a special scenario, different from the generally accepted ideas.
The researchers suggest several possible explanations for this anomaly. One option is the so-called “cleaning out of the center”, which can occur when two giant galaxies merge. In this process, the binary black hole formed after the collision ejects a significant number of stars from the center, which reduces their average speed, but has virtually no effect on the mass of the black hole itself. Another hypothesis links ultramassive black holes to ancient quasars — active galactic nuclei that, in the early stages of the Universe, absorbed huge amounts of matter, rapidly increasing their mass.
In the coming years, the Euclid mission and the upcoming ELT telescope will provide more data on such objects. Euclid is expected to detect hundreds of thousands of gravitational lenses, which will help to study the evolution of galaxies and their central black holes in greater depth. These discoveries could significantly change our understanding of how the most massive structures in the Universe form and evolve.
