The most powerful microquasar in history has been discovered in our galaxy.

Quasars are distant galaxies that are still in the process of formation. They are extremely bright objects in space; astronomers initially considered them to be stars before labeling them as "quasi-stellar objects."

Modern science has established that their immense energy is a manifestation of the activity of a supermassive black hole, which presumably exists at the center of every galaxy. There is even suspicion that black holes represent the cores of globular star clusters.

In quasars, black holes often absorb material so intensely that they cannot physically take in everything they attract, resulting in excess material being ejected from their poles in the form of gigantic plasma jets, often accelerated to near-light speeds. These are referred to as relativistic jets. If a black hole is oriented such that one of these jets points towards Earth, the object appears especially bright. This type of object is called a blazar: "a blazing quasar" (from the word blaze).

Until recently, such phenomena were expected to be observed only far beyond our galaxy, but researchers have recently focused on an intriguing object in the direction of the constellation Sagittarius — V4641 Sagittarii. It is estimated to be located about 20,000 light-years away from us. Notably, at 26,000 light-years from Earth — also in Sagittarius — lies the center of the Milky Way. This means the object is relatively close to the supermassive black hole at the center of our galaxy, which contains a mass equivalent to four million suns.

However, this particular object is not supermassive. It is only a few times heavier than the Sun, yet it behaves like a true quasar: it fountains relativistic jets, one of which is directed towards us, making it not just a quasar, but a blazar. Scientists have termed this phenomenon a microquasar.

As written by a team of researchers from Poland, the USA, Mexico, and other countries in the journal Nature, they determined that this black hole has a mass roughly equivalent to six suns and is "devouring" a companion star. The system is very compact: the predator and its prey complete an orbit around their common center of mass in less than three Earth days.

It is worth noting that several dozen such microquasars have actually been observed in the Milky Way, but the photons from V4641 Sagittarii possess an exceptionally high energy — up to 200 tera-electronvolts. This is several orders of magnitude higher than those from other such sources. Astronomers conclude that a significant portion of the galactic radiation constantly bombarding Earth originates from microquasars.