An article published in the journal Nature Astronomy reports the results of a study of seven galaxy clusters which contain various supermassive black holes that offers evidence that outbursts generated at these black holes help cool the gas they feed on. A team of researchers used observations with multiple instruments to examine seven galaxy clusters. Outbursts in the form of jets from the supermassive black holes in those clusters cool the gas by forming thin filaments. Some of that gas will eventually flow back toward those black holes, triggering more outbursts in a mechanism in which the black holes “cook” their own meals.
Galaxy clusters can even be made up of hundreds of gravitationally bound galaxies. The image (Perseus Cluster: X-ray: NASA/CXC/SAO/V. Olivares et al.; Optical/IR: DSS; H-alpha: CFHT/SITELLE; Centaurus Cluster: X-ray: NASA/CXC/SAO/V. Olivaresi et al.; Optical/IR: NASA/ESA/STScI; H-alpha: ESO/VLT/MUSE; Image Processing: NASA/CXC/SAO/N. Wolk) shows the Perseus and Centaurus galaxy clusters observed in combinations of different electromagnetic bands. Filaments of very hot gas are detected at X-rays and represented in blue while the cooler ones detected at visible frequencies are represented in red.
The centers of galaxy clusters contain the most massive galaxies in the universe, which in turn contain supermassive black holes whose masses can be billions of times the Sun’s. Observations in various electromagnetic bands have been precious to confirm a theoretical model that predicts a mechanism in which a supermassive black hole partially feeds itself. The model predicts a relationship between the brightness of the filaments of very hot and hot gas at the centers of galaxy clusters.
X-ray observations were conducted with NASA’s Chandra X-ray Observatory, while observations at visible frequencies were conducted with the MUSE (Multi Unit Spectroscopic Explorer) spectrograph on ESO’s Very Large Telescope (VLT) in Chile and the SITELLE (Spectromètre Imageur à Transformée de Fourier pour l’Etude en Long et en Large de raies d’Emission) spectrometer at the CFHT (Canada France Hawaii Telescope).
The researchers observed the behaviors of supermassive black holes and the gas in the areas around them. The results confirm that the outbursts in the form of jets cool the gas into thin filaments and that some of that gas will eventually flow back toward those black holes, triggering more outbursts. More gas can be captured by the black holes but the mechanism is partly self-sustaining with the black holes “cooking” their own meals.
This result also shows a similarity between these filaments linked to supermassive black holes and the tails of so-called jellyfish galaxies whose gas is stripped away as they travel through the gas that surrounds them. This shows a connection between these objects and suggests that a similar process might be at work.
The processes at work around supermassive black holes have long been the subject of study for several reasons. These extreme objects allow to test cosmological models in search of advances toward a unified theory while in this case, the interest is in the interactions that occur between black holes and the areas around them. The influence of supermassive black holes on their host galaxies can be remarkable, and this study offers some new insights into this topic.
