A new study has detected two pairs of supermassive black holes in two dwarf galaxies on a collision course.
The observations were obtained from Chandra X-ray data and could provide useful insights into the evolution of black holes in the early universe.
The result was published in The Astrophysical Journal.
New study overcomes observational challenges to identify black holes in dwarf galaxies
Dwarf galaxies are small and compact galaxies containing stars with a total mass of less than about 3 billion times that of the Sun. Scientists believe that the early universe was full of dwarf galaxies that merged with each other to create larger galaxies visible today. A new study led by researchers at the University of Alabama has used a systematic survey of deep Chandra X-ray observations, compared with infrared data from the Wide Infrared Survey Explorer (Wise) and optical data from the Canada-France-Hawaii Telescope (Cfht), to overcome observational challenges in studying dwarf galaxies. The study found examples of black holes on collision courses in nearby large galaxies but had previously failed to find such evidence in dwarf galaxies due to their weak luminosity at great distances.
Since the material surrounding black holes can be heated to millions of degrees, producing large amounts of X-rays that can be detected by Chandra, the use of the space telescope has been particularly valuable. The team, as evidence of the presence of two black holes, traced bright pairs of X-ray sources in the colliding dwarf galaxies, thus obtaining the first results. "We have identified the first two distinct pairs of black holes in colliding dwarf galaxies," says Olivia Holmes of Ua and co-author of the study. "By using these systems as models, we can deepen our understanding of the first galaxies present in the primordial universe, their black holes, and the star formation caused by the collisions."
Two pairs of colliding black holes detected in distant galaxy clusters
A recent study has detected two pairs of supermassive black holes in two colliding dwarf galaxies. The observations were obtained from Chandra's X-ray data and could provide valuable information on the evolution of black holes in the early universe. The first pair of black holes was found in the Abell 133 galaxy cluster, located 760 million light-years from Earth, while the second pair was located in the Abell 1758S cluster, approximately 3.2 billion light-years away. The researchers suggest that these dwarf galaxies and black holes have evolved over billions of years through repeated mergers, with the colliding galaxies in Abell 133 already showing signs of a new galaxy formation, named "Mirabilis." The dwarf galaxies in Abell 1758S, on the other hand, were nicknamed "Elstir" and "Vinteuil" and captured in the early stages of the fusion process.
On the left, the image of the new galaxy Mirabilis, on the right, the collision between Elstir and Vinteuil. Both images were obtained by combining optical and X-band observations. Credits: NASA/CXC/Univ. of Alabama/M. Micic et al./Gemini Observatory/NSF/AURA.
These new details on black hole mergers and the activity of dwarf galaxies can provide new and important information about the past of our galaxy. Furthermore, researchers hope that further observations of these two systems will allow them to analyze the processes underlying the evolution of galaxies and their baby black holes in the early stages of the universe.
