The new observation results from NASA's Chandra X-ray observatory have made a big step in explaining how a special black hole group can stop producing high-speed rays. This result shows that the aforementioned black holes have a mechanism to control their growth rate.
Black holes also have many sizes: from giants, including black holes in quasars that are millions of times more massive than billions of times the mass of the sun, until small black holes with a mass of about 7 up to 25 times the mass of the sun. Some black holes with the same weight as stars emit extremely powerful molecular and radiation rays, just like the phenomenon occurs in quasars, and are called microscopic quasars.
The new study explores famous micro-quasars in our galaxy, as well as areas close to the horizon. This system, called GRS 1915 + 105 (GRS 1915 for short), contains a black hole just 14 times larger than the sun, which absorbs matter from nearby companion stars. When the stream of matter is twisted toward the black hole, they form a disk and grow.
This system shows the unpredictable complex variation that takes place from a few seconds to several months, including 14 different transformations. This transformation is due to an unknown relationship between GRS 1915 disk and radio beams.
Chandra Observatory uses a spectrophotometer that has observed GRS 1915 eleven since 1999. The study has revealed that the beam in GRS 1915 can be temporarily stopped if there is a hot wind, which can be transmitted. now due to X-rays, radiating from the growing disk surrounding the black hole. This wind is thought to have turned off the rays by taking away the energy-supplying materials for those rays. Conversely, when the wind stops the rays appear again.
Joseph Neilsen, a Harvard graduate student and lead author of a paper published in Nature, said: "We think the sparks that blow out the black hole are like two warring factions. Sometimes a party is fighting, but for some reason, the other side has an advantage. '
The latest results from Chandra also show that wind and rays carry the same amount of matter out of the black hole. This is evidence that black holes somehow adjust their growth rate. This may involve weight changes due to beam or wind flow from the disk. Self-regulation is a common topic when discussing giant black holes, but this is the first clear evidence of this mechanism in black holes the size of stars.
Co-author Julia Lee - assistant professor of astronomy at the Harvard-Smithsonian Center for Astrophysics - said: 'It is interesting that we may be on the right track to explain the same two mysteries. time: how to stop rays from black holes and how black holes adjust their growth rate. Perhaps black holes can adjust themselves better than financial markets. ' Although micro-quasars and quasars differ in weight, it can be millions of times, but they still have a common feature in performance when taking into account their different appearance sizes.
Neilsen said: 'If quasars and microscopic quasars behave very differently, then we will face a big problem in answering the question why the gravitational force acting on them is the same. So our results really reassure us because it's another connection between different types of black holes. '
The period of change in black hole activity varies in proportion to its weight. For example, if GRS 1915 takes an hour to perform changes, this figure is equivalent to 10,000 years for a massive black hole one billion times more massive than the sun.
Lee said: 'We cannot hope to find such interesting details in a giant black hole system. So we can learn a lot about black holes just by looking at these small black holes. ' Scientists still do not know what causes the rays in the black hole to function again after the wind is turned off. This is still one of the mysteries not yet answered by astronomy.
Neilsen said : 'Every central observatory, both on the ground and in space, has been used to study this black hole over the past two decades. Although we still haven't got all the answers yet, I think our research is on the right track. '
The study was carried out with the Chandra Observatory, a high-energy spectrometer. These results were published in the March 26 issue of the journal Nature. NASA's Marshall Aerospace Center in Huntsville, Ala., Controlled the Chandra program in Washington. The Smithsonian Astrophysical Observatory runs Chandra's flight and scientific research activities from Cambridge, Mass.
Refer:
Joseph Neilsen & Julia C. Lee.Accretion disk winds as the jet suppression mechanism in the microquasar GRS 1915 105. Nature, 2009;458 (7237): 481 DOI: 10.1038 / nature07680