Two supermassive black holes in the space of a solar system

Recent research has made it possible to understand in detail one of the exotic phenomena caused in their surroundings by two black holes with a combined mass of about 40 million times that of the Sun (ten times more than that of the supermassive black hole at the center of our galaxy) that They are separated by only 26,000 million kilometers.

The study was carried out by a team led by astrophysicist Lorena Hernández García, from the University of Valparaíso in Chile. The research has been done based on observations made by NASA’s Swift space observatory.

This pair of supermassive black holes is located at the center of a galaxy called 2MASX J21240027+3409114, located one billion light-years away, in the boreal constellation of Cygnus (The Swan).

These black holes orbit each other and take 130 days to make a complete revolution. They are getting closer to each other. It is estimated that they will collide and merge within about 70,000 years.

The most striking of the effects that this pair of black holes exerts on its cosmic neighborhood is the deformation of an extensive cloud of gas.

“We believe that the gas cloud enveloped the black holes. As they orbit each other, the black holes interact with the cloud, disturbing its gas and consuming it. This produces an oscillatory pattern in the light that comes from that system,” explains Hernández García.

This pattern began to be observed after the detection of a rare flash in March 2021 by the ZTF (Zwicky Transient Facility) at the Mount Palomar astronomical observatory in California, United States.

“Although it was originally thought that this flash corresponded to a supernova, the new bursts in 2022 made us think about other explanations,” explains astrophysicist Alejandra Muñoz Arancibia, from the University of Chile and co-author of the study. “Each subsequent event has helped us improve our model of what is happening in the system.”

Since the first flash, ZTF has detected bursts from the source, cataloged with the name “AT 2021hdr”, at intervals of between 60 and 90 days. In November 2022, Hernández García and his colleagues began to observe the area where this phenomenon occurs using Swift. Thanks to Swift, they were able to determine that the binary black hole system produces oscillations in ultraviolet and X-ray light on the same time scales captured by the ZTF in the visible range.

Initially, researchers thought the signal could be the byproduct of normal activity at the galactic center. They then considered the possibility that the tearing apart of a star that got too close to one of the black holes was the cause.

Finally, they decided on another possibility: the breakup of a gas cloud, a cloud that was initially larger than the binary system itself. When the cloud encountered the black holes, gravity tore it apart, and some of the torn material formed filaments around the pair of holes. Furthermore, the friction began to heat her up. The gas became particularly dense and hot near black holes. As the holes of the binary system move along their orbital path, the complex interaction of forces expels some of the gas from the system with each rotation. These interactions produce the fluctuating light observed by Swift and ZTF.

Artistic recreation of the pair of supermassive black holes deforming and destroying the gas cloud. (Image: NASA/Aurore Simonnet/Sonoma State University)

Hernández García and his colleagues plan to continue observations of AT 2021hdr to better understand the system and improve their models. They are also interested in studying their home galaxy, which is currently merging with another nearby galaxy, as they discovered during the research.

The study is titled “AT 2021hdr: A candidate tidal disruption of a gas cloud by a binary super massive black hole system.” And it has been published in the academic journal Astronomy and Astrophysics. (Source: NASA / NCYT by Amazings)