14 DAY TRIAL // Astrophysicists investigating the latest results provided by NASA's Chandra X-ray Observatory have discovered something truly amazing, and namely that a certain class of black holes has the ability to regulate its own growth, by simply shutting down or reducing the amount of high-speed particles they usually emit. The lack of the jets prevents matter from being vented into outer space, and thus increases the mass of the formation, whereas amplifying the emissions may lead to a larger loss of mass.
At this point, astronomers have identified roughly two classes of black holes: those that are supermassive, with masses of millions to billions of times larger than that of our own Sun, and which include quasars, and smaller, regular star-sized ones that are only a few tens of times larger than our central star. However, some of these smaller ones emit very powerful jets of super-charged particles, which have made astrophysicists dub them “micro-quasars.”
“We think the jet and wind around this black hole are in a sort of tug of war. Sometimes one is winning and then, for reasons we don't entirely understand, the other one gets the upper hand,” Harvard graduate student Joseph Neilsen, who has also been the lead author of a new paper detailing the finds, published in a recent edition of the scientific journal Nature, explains. He argues that the relatively-small black hole actually regulates its accretion process, a trait that is common in supermassive black holes, but which has never before been identified or proven in smaller ones.
“It is exciting that we may be on the track of explaining two mysteries at the same time: how black hole jets can be shut down and also how black holes regulate their growth. Maybe black holes can regulate themselves better than the financial markets!” Harvard-Smithsonian Center for Astrophysics Astronomy department assistant professor Julia Lee, who has also been a co-author of the new study, jokes.
“If quasars and micro-quasars behave very differently, then we have a big problem to figure out why, because gravity treats them the same. So, our result is actually very reassuring, because it's one more link between these different types of black holes. Every major observatory, ground and space, has been used to study this black hole for the past two decades. Although we still don't have all the answers, we think our work is a step in the right direction,” Neilsen adds.