Astronomers have discovered two supermassive black holes in the galaxy 2MASX J21240027+340911 that are increasingly spiraling closer together while simultaneously pulling in interstellar material.
The galaxy 2MASX J21240027+340911 has been known to host an active core for about a decade. At its center, a supermassive black hole is consuming interstellar material, whether gas or dust, as it approaches too closely. Recently, astronomers detected a repeating signal from this object, indicating a more complex structure: not just one, but two supermassive black holes are situated at the core of this galaxy – and they are sharing a meal together.
Simulation of the monstrous black hole pair swirling in a gas cloud NASA/Aurore Simonnet. (Photo: Sonoma State University).
The total mass of this pair of black holes is 40 million times that of the Sun, and they are separated by about a light-day, equivalent to approximately 26 billion kilometers. This pair of black holes is predicted to collide in about 70,000 years, and they are spiraling closer together with a cycle of 130 days. It is this orbital motion that has created the observed repeating phenomenon.
In a study published in the journal Astronomy & Astrophysics, lead author Lorena Hernández-García, an astrophysicist at the Millennium Institute of Astrophysics and the University of Valparaíso in Chile, stated that this is a very unusual event. “We believe that a gas cloud has enveloped the black holes. As they orbit each other, these black holes interact with the cloud, disturbing and consuming its gas. This creates an oscillating pattern in the light emitted from the system.”
The research team considered several possibilities. This could be a common behavior in an active core. Alternatively, it might be a star that comes too close to a supermassive black hole, gets torn apart, and is subsequently consumed slowly. However, the scenario of a pair of supermassive black holes enveloped in a gas cloud, “dining” while orbiting each other, is the most convincing hypothesis.
The research team intends to continue monitoring this event to better model what is happening, as well as to study the host galaxy undergoing the merger process. This galaxy is located 1 billion light-years away from Earth.
