James Webb Space Telescope sees an ancient black hole dance with colliding galaxies

The James Webb Space Telescope (JWST) has captured a fascinating celestial spectacle, showcasing the dynamic interaction between a supermassive black hole and merging galaxies dating back less than a billion years after the Big Bang. This groundbreaking observation has profound implications for our understanding of the early universe, shedding light on the growth of galaxies and supermassive black holes during their infancy.

Utilizing the advanced capabilities of JWST, astronomers observed an intriguing phenomenon referred to as the "dance" between a supermassive black hole and two satellite galaxies. Remarkably, these observations provide valuable insights into the cosmic processes that drove the formation and evolution of galaxies and their central supermassive black holes.

The targeted supermassive black hole in question is actively feeding on its surrounding matter, effectively generating a bright quasar known as PJ308-21. From the perspective of JWST, this quasar appears to us as it existed less than one billion years after the formation of the universe. Designated as an active galactic nucleus (AGN), PJ308-21 resides in a galaxy presently undergoing a merging process with two massive satellite galaxies.

The research team not only determined that this black hole boasts a mass equivalent to two billion suns but also discovered that both the quasar and galaxies involved in this merger display a high level of evolution. The prevailing assumption had been that such advanced entities should not exist in the early cosmos, making this finding a truly surprising revelation. In essence, the convergence of these three galaxies is expected to deliver substantial amounts of gas and dust to the supermassive black hole, fueling its growth and sustaining PJ308-21's luminosity.

Roberto Decarli, the team leader from Italy's National Institute for Astrophysics (INAF), emphasized the significance of their study, stating that it exposes the remarkably efficient and turbulent growth experienced by the black holes at the centers of early quasars, as well as the galaxies hosting them. This growth is aided by the rich galactic environments within which these sources originated.

Obtained in September 2022 using JWST's Near InfraRed Spectrograph (NIRSpec) as part of the 1554 Program, these data point to a significant milestone in astronomical advancements. The investigation of the merger involving PJ308-21's host galaxy and its two satellite galaxies demanded resourcefulness and perseverance from the team, ultimately resulting in images with pixel-level accuracy exceeding 99%.

The phenomenon of a quasar arises when a supermassive black hole, with a mass millions or billions of times that of our sun, becomes enveloped by an abundance of gas and dust. This material coalesces into a flattened structure known as an accretion disk, swirling around the black hole while inexorably feeding it.

Powered by the intense gravitational forces within the black hole, the accretion disk grows exceptionally hot, generating temperatures of up to 120,000 degrees Fahrenheit (67,000 degrees Celsius). Consequently, the incandescent accretion disk radiates energy across the electromagnetic spectrum, often exceeding the combined luminosity of all the stars in the surrounding galaxy. Thus, quasars like PJ308-21 assume a place as some of the most luminous objects recorded in the universe.

While black holes themselves lack distinctive features indicating their level of evolution, their associated accretion disks (and consequently the quasars) possess such attributes. Similarly, galaxies can be classified in terms of "age" based on this same principle.

During the early stages of the universe, hydrogen and a small amount of helium constituted its elemental composition. These elements provided the foundation for the formation of the first stars and galaxies. Over time, as these celestial bodies completed their life cycles, they generated heavier elements, commonly referred to as "metals," via supernova explosions. The dispersion of these metals shaped future generations of stars and galaxies. It resulted in a steady increase in the metallicity of stars and, by extension, galaxies throughout the universe's history.

Evaluating PJ308-21, the team discovered that the active central region is rich in metals, sharing a similar characteristic with most AGNs. Additionally, gas and dust in its vicinity undergoes a process called "photoionization," where photons emitted by surrounding particles supply the energy needed for electrons to escape atoms, creating charged ions.

One of the merging satellite galaxies also exhibits metal-rich properties, with part of its matter undergoing partial photoionization driven by the electromagnetic radiation emitted by the quasar. In contrast, the second satellite galaxy appears metal-poor and experiences photoionization due to a burst of rapid star formation.

A key asset in exploring this early universe quasar is JWST's infrared capability. Due to the universe's expansion, the light signals emitted by PJ308-21 during its over 12-billion-year journey have experienced substantial redshift, shifting their wavelengths toward the red end of the electromagnetic spectrum. JWST's exceptional sensitivity to infrared light enables it to capture and analyze these "high-redshift" or "high-z" phenomena, including PJ308-21, offering insights into their origins and characteristics.

Federica Loiacono, an astrophysicist from INAF and a team member, emphasizes the vital role played by JWST in extending knowledge and paving the way for exceptional observations. By harnessing the near and mid-infrared sensitivity of JWST, scientists can conduct exceptionally precise studies of the quasar's spectrum and its companion galaxies, acquiring invaluable data on distant cosmic systems and pushing the boundaries of our comprehension.

Publishing their findings in June 2024 in the journal Astronomy & Astrophysics, the team's research carries profound implications for further unraveling the mysteries of the early universe and the cosmic dance between supermassive black holes and merging galaxies. With its remarkable capabilities, the James Webb Space Telescope has revolutionized our understanding of our cosmic origins and continues to astound scientists with its remarkable discoveries.