The apparent stillness of two supermassive black holes

Space mission Srg / E. Rosetta Locate Two galaxies It is considered so far quiet which instead shows semi-periodic eruptions. The authors of the discovery team of scientists from Max Planck Institute With participationIanaf. The nuclei of these galaxies emit strong glows of X-rays every few hours, reaching peak brightness similar to that produced by an entire galaxy. This pulsating behavior could be caused by a star or celestial body of similar mass orbiting around A supermassive black hole It is located in the central regions of the Galaxy. The discovery, which was published today in the magazine natureThis will help scientists better understand black hole activity in low-mass galaxies.

I Quasar a Active galactic nuclei (Agn) are the beacons of the distant universe. The brightness of their central region, fueled by a supermassive black hole adding to massive amounts of matter, could be thousands of times the brightness of a galaxy like ours. Milky Way.

Ricardo Arcodia, PhD student at Max Planck, first author of the study published in the journal Nature, says: “In a survey of the whole sky of erosion, we found two previously quiet galaxies now showing sharp and nearly strong periodic pulses in X-rays. These things are very rare: so far, in fact. “, Only two sources with similar properties were known. Since this new type of source only appears strange in x-rays, we decided to use the eRosita mission data and immediately found two more.”

The eRosita Telescope currently scans the entire sky with X-rays and the data it constantly collects is ideal for searching for transient events, just like these energy revolutions. Both new sources discovered by eRosita showed significant X-ray contrast within a few hours, a feature confirmed by following observations with space telescopes. Xmm-Newton e The most beautiful. Unlike the two similar objects known to date, the galaxies of these new sources discovered by eRosita were until now thought to host quiet black holes. “These two galaxies look completely normal, with somewhat limited mass and no indication of any prior strange activity -” explains Andrea Merloni of Mpe, lead researcher for eRosita. Without these sudden and repeated bursts of X-rays we would have been ignoring them.

A quasi-cyclic emission like the one discovered by e-Rosita is usually associated with binary systems. The data indicate that if these explosions were caused by an object orbiting the black hole, then its mass should be much smaller than it, such as the mass of a star or even a white dwarf. These celestial bodies can interact with the black hole and surrounding materials during each orbit.

“We do not yet know what could trigger the eruption of these x-rays – Arkodia confirms – but we do know that the areas around the black hole were quiet until recently, so it is not necessary to assume that an accretion disk like the disk surrounding black holes in active galaxies to move These phenomena. Additional X-ray monitoring campaigns for these organisms will help confirm or exclude this scenario. ”If the origin of these explosions is A Binary system, It will be an interesting solution because in the future it will allow us to combine both observations of electromagnetic waves and gravity, thus opening new horizons.Multiple letter astrophysics– Concludes Gabriel Ponti, INAF Researcher in Milan.