2023-06-23 04:00:14
About 200 years ago, the supermassive black hole at the center of our galaxy, Sagittarius A* (Sgr A*), had a brief burst in its slumber. This is revealed by an international team of researchers, led by Frédéric Marin, CNRS researcher at the Strasbourg Astronomical Observatory (The Strasbourg Astronomical Observatory is located on the historic campus of…).
NASA’s new IXPE dataset (In information technology (IT), a datum is a basic description, often…) shows high activity (The term activity can refer to a profession .) of Sgr A* 200 years ago, having probably swallowed gas and dust nearby. The echo of this past activity, in orange, is combined with data from Chandra (The Chandra satellite is an X-ray telescope. It was launched in 1999 by the shuttle…), another NASA observatory, in blue, which only shows the light (Light is all the electromagnetic waves visible to the eye…) direct from the galactic center. The first image offers a wider view of the center of the Milky Way (The Milky Way (also called “our galaxy”, or sometimes…) obtained by Chandra.
Credits: NASA/CXC/SAO/IXPE
Sgr A*, a gigantic object with a mass four million times that of the Sun, had a brief bout of activity 200 years ago, before falling back into a dormant phase. He engulfed matter (Matter is the substance that makes up any body having a tangible reality. Its…) which had approached a little too close before falling back into a deep sleep. Fortunately, this activity had no impact on our Earth, the distance that separates us from Sgr A* being sufficient to protect us from this radiation.
Thus, the researchers detected an “echo” in X-rays testifying to this former activity of Sgr A*. For comparison, imagine a small firefly hiding in a forest that suddenly becomes as bright as the Sun in the sky: astronomers have measured such a difference in activity.
To carry out their research, the scientists used NASA’s IXPE (Imaging X-ray Polarimetry Explorer) satellite, which was able for the first time to detect polarization (the polarization of electromagnetic waves; the polarization due to moments …) X-rays with great precision and to determine the source. A bit like a compass (A compass is a navigational instrument consisting of a needle…), polarized X-rays point towards their source: Sgr A*. The researchers are continuing their work on Sgr A* to try to determine the physical mechanisms necessary for a black hole (In astrophysics, a black hole is a massive object whose gravitational field is so intense…) to change from a state asleep to an active state.
The echo emitted during the eruption of Sgr A* (located outside the image). The luminosity of the sources of radiation (Radiation, synonymous with radiation in physics, designates the process of emission or…) (or of the echo, for the IXPE) is converted into an audio spectrum, 51 octaves in below the real frequencies (52 octaves for the echo).
Credits: NASA/CXC/SAO/IXPE
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