Triggered black hole in M83
A microquasar hyperactive challenges every model of emission. Baptized MQ1, could send in the attic theories that postulate the existence of the black holes of intermediate mass. First author of the study, that was published today in Science Express, is Piedmont Roberto Soria.
Artistic representation of a microquasar as MQ1, the black hole discovered in the galaxy M83.
Credits: NASA Chandra
Over the past 20 thousand years there has been gobbled up an amount of matter equal to hundreds, maybe even thousands of times higher than that in theory it deserved. Freeing the stored energy in the form of jets from the terrific power, amounting to a few million times that of the Sun, the winds of particles are so intensive that overload the Southern Pinwheel – so it is named the galaxy that hosts them, otherwise known as M83 that can be found at about fifteen million light years away from us.
The protagonist of so much upheaval is MQ1, a microquasar (a stellar-mass black hole with accretion disk) that measures surprisingly modest: not even a hundred solar masses. And it is the reliability and accuracy of the measurement of its mass the beam on which rests the importance of the discovery, published some weeks ago in the pages of Science Express, a team of scientists led by Piedmont, Roberto Soria, currently a researcher at ICRAR Perth, Australia.
It is already known that black holes are hyperactive, energetic enough to affect their emissions with the galaxies in which they are located. The problem is to assess the mass accurately. Those of which we speak are not the supermassive black holes at the heart of galaxies but they are normal (so to speak) black holes of stellar mass. “Stellar mass”, yet, the unit is a bit elusive. Elastic to the point that its emission intensity of some subjects particularly turbulent, first of all the ULX (ultraluminous X-ray sources), led astrophysicists to assume the existence of so-called black holes of intermediate mass. This is because, as a black hole can assume commitment, there is a limit to the power that is capable of expressing: a threshold that depends, in fact, by its mass, and which goes under the name of limit Eddington.
If, therefore, the energy is expressed too much to be compatible with a black hole of small size, probably the responsible person must wear a medium, right? But here’s the surprise. After keeping it under observation for one year, and the measures were taken with three instruments (the tireless Space Telescope for NASA’s Chandra X-ray, the Hubble Space Telescope for optical and infrared rays, the Australia Telescope Compact Array for the band radio), scientists have come to the conclusion that M83 contained a black hole of medium mass. It was a bit like coming across a subcompact small but misleading, able to ridicule a Formula 1 racing car: the book says 40 horses, but that it gives off merrily at least a hundred times more, in spite of Motor Vehicles and the laws of mechanics.
“We estimate that MQ1 has a power three or four times higher than the Eddington limit, which was thought to be the most accessible,” says Soria. Of course, keep in mind that when we talk about the Eddington limit, we are not referring to an insuperable threshold, such as for example the speed of light. “It’s speed limit, so to speak, indicative”. And what does it indicate? “Roughly, the maximum brightness that a black hole can reach in terms of photons.”