Supermassive black holes are found deep within the massive galaxies at the center of galaxy clusters. The atmospheres of galaxy clusters are full of plasma and extremely hot – about 50 million degrees Celsius – but these temperatures typically decrease over time, allowing new stars to form. In a process known as feedback, the black hole occasionally reheats the gas around it by ejecting violent bursts from its center, preventing cooling and star formation.

The National Science Foundation’s Green Bank Telescope (GBT) has revealed new information about mysterious radio bubbles surrounding a supermassive black hole. In a new study, scientists watched one of the most energetic outbursts ever seen from a supermassive black hole.

Jack Orlowski-Scherer, a lead author of this publication, said: “This is what happens when you feed a black hole and violently expel it with a gigantic amount of energy.”

The Sunyaev-Zeldovich (SZ) effect, a subtle distortion of the cosmic microwave background (CMB) caused by scattering by hot electrons in the cluster gas, was used by the astronomers to image MS0735 using the MUSTANG-2 receiver on the GBT. For reference, the CMB was produced 380 thousand years after the Big Bang. The SZ effect signal, where MUSTANG-2 senses, mainly monitors thermal pressure.

Tony Mroczkowski, an astronomer at the European Southern Observatory who was part of this new research, said: “With the power of MUSTANG-2, we can look into these cavities and determine exactly what they’re filled with and why they don’t collapse under pressure.”

These new results confirm previous findings that at least some pressure support in the cavities is due to non-thermal sources, including relativistic particles, cosmic rays and turbulence, as well as a small contribution from magnetic fields. They represent the deepest high-fidelity SZ imaging of the thermodynamic state of voids in a galaxy cluster to date.

Co-author Tracy Clarke, an astronomer at the US Naval Research Laboratory and VLITE Project Scientist, said: “We knew this was an exciting system when we studied the radio core and lobes at low frequencies, but we’re only now beginning to see the full picture.”

Contrary to previous studies, new imaging made by the GBT considers the idea that the pressure support within the bubbles may be more complex than initially believed, combining thermal and non-thermal components. The scientists also used pre-existing X-ray measurements from NASA’s Chandra X-ray Observatory, which provide an additional perspective on the gas detected by MUSTANG-2.

Orlowski-Scherer said: “This work will help us better understand the physics of galaxy clusters and the cooling current feedback problem that has been vexing many of us for some time.”

Magazine reference:

  1. John Orlowski-Scherer, Saianeesh K. Haridas et al. GBT/MUSTANG-2 9″ resolution imaging of the SZ effect in MS0735.6+7421. Astronomy and astrophysics. DOI: 10.1051/0004-6361/202244547