A gigantic dormant black hole triggers star formation

Image credit: DERF/NC

American astronomers have detected an unusual number of stars in the distant galaxy cluster SpARCS1049. The lack of control in their formation is due to the inactivity of the supermassive black hole that must regulate them in that sector of the universe.

A team of scientists from NASA’s Chandra X-ray Observatory has concluded that the overpopulation of stars that can be seen in the galaxy cluster called SpARCS1049 has its origin in the lack of activity of a supermassive black hole, which precisely fulfills the function of regulate star formation. According to a press release, the discovery could shed light on the consequences of black hole inactivity in different circumstances.

SpARCS1049 is exactly 9.9 billion light years distant from Earth. It is a galaxy cluster, that is, a structure made up of hundreds or thousands of galaxies, endowed with hot gas and with large X-ray emissions. Usually, a supermassive black hole is located in the central galaxy of the cluster, producing energy that allows you to control the formation of stars.

However, previous observations made with NASA’s Hubble Space Telescope and the Spitzer Space Telescope had indicated that in SpARCS1049 stars were born at an impressive speed, well above the known average. The formation of around 900 new mass suns per year was recorded, a rate 300 times faster than that observed in our galaxy, the Milky Way.

The astronomers indicated that with this speed all the stars found in the Milky Way could form in around 100 million years. On the contrary, it is known that our galaxy has an age that exceeds ten billion years, consequently being an extremely short period for the formation of all the stars that compose it.

Denser and colder gas
From these data, astronomers began to wonder about the reasons for this anomaly in the galaxy cluster SpARCS1049. Something would have to be wrong for the rate of star formation to be so explosive and inordinate. Looking for more details, the specialists determined that the unusual stellar production takes place about 80 thousand light years away from the center of SpARCS1049, in a region far from any of the galaxies that are part of the cluster.

The data provided by the Chandra X-ray Observatory allowed us to solve this question. It was found that in the sector where there is a greater generation of stars, the gas is denser than in the average for the area and has cooled to a temperature of around 10 million degrees, when the usual temperature in the cluster of galaxies studied it is located at 65 million degrees.

The lower temperatures allow a greater production of stars, explaining the increase in rhythm and quantity. But the astronomers also concluded that the cooling is due to the inactivity of the supermassive black hole located at the center of SpARCS1049, which should regulate stellar production by emitting energy to its surroundings.

A starving sleeping black hole
Everything indicates that the giant black hole has fallen asleep due to the absence of a fuel source that powers its activity. It is that the denser gas that could feed it has moved considerably away from the center of the galaxy cluster, due to a collision produced at some point between two smaller groups of galaxies. Precisely this clash allowed the creation of SpARCS1049.

Finally, scientists believe that a better understanding of this type of supermassive black holes without activity could increase the knowledge of specialists about the conditions of formation of the first stars in the universe.