Black Hole Jets Seen Forming in Real-Time
January 22, 2025 by Matt Williams
A short time ago, astronomers observed a distant supermassive black hole (SMBH), located in a galaxy 270 million light-years away in the constellation Draco. For years, this galaxy (1ES 1927+654) has been the focus of attention because of the Active Galactic Nucleus (AGN) at its core. It all began in 2018 when the SMBH’s X-ray corona mysteriously disappeared, followed by a major outburst in the optical, ultraviolet, and X-ray wavelengths. Astronomers began watching it closely, but what they saw next was completely unexpected!
As highlighted in previous observations, the SMBH's behavior suggested that it was consuming a stellar remnant, which was likely a white dwarf. In addition, astronomers noted a dramatic increase in radio emissions and the formation of plasma jets extending from the black hole, a phenomenon that all occurred over the span of a year. A new paper, led by the University of Maryland Baltimore County (UMBC), describes how they tracked a plasma jet forming in real time, a groundbreaking observation in the realm of astrophysics.
The team’s research was published in the Astrophysical Journal Letters and led by UMBC associate professor Eileen Meyer. She was joined by multiple colleagues from UMBC’s Department of Physics and Astronomy, the Joint Space-Science Institute (JSI), and the Center for Space Science and Technology (CSST). The research team also included scholars from the Space Telescope Science Institute, the Technion Israel Institute of Technology, and the Joint Institute for Laboratory Astrophysics (JILA), along with researchers from the Institute for Space Astrophysics and Planetology and NASA Goddard Space Flight Center.
Forming a Jet
Astronomers have previously observed jets emanating from the poles of several SMBHs throughout the Universe. In several cases, these jets have been shown to accelerate gas and dust particles to velocities that approach the speed of light, earning the designation "relativistic jets." In some scenarios, astronomers have documented jets that extend thousands, or even hundreds of thousands of light-years from their respective host galaxies. These jets eject material over incredible distances, and in some cases, they even catalyze the formation of new stars along their pathways.
In the current observation of 1ES 1927+654, the jet materialized following a period of variable activity, characterized by the AGN consuming significant amounts of matter and becoming over 100 times brighter within just a few months—an extraordinary shift that typically transpire over thousands or millions of years in other contexts. After witnessing nearly a year of consistently high X-ray emissions, the black hole eventually quieted down throughout 2020, only to ramp up its activity once again in 2023. During this resurgence, it began to emit radio waves at an intensity 60 times greater than its previous emissions, a scenario that has never before been documented in real time for an SMBH.
Significant Observations
Using radio observations from telescopes such as the Very Large Array (VLA) and the Very Large Baseline Array (VLBA), the team was able to obtain high-resolution radio imaging of the SMBH housed at the core of 1ES 1927+654. These images clearly illustrated the formation of two plasma jets extending outward from the black hole's poles between 2023 and 2024. Notably, scientists have recently identified a category of "changing-look AGNs," referring to supermassive black holes that exhibit far greater radio frequency activity compared to when they were first observed.
In previous examples, astronomers had largely presumed that major shifts must have occurred in the interim since their observations were years or decades apart. However, in this instance, astronomers were able to witness these transformations happening in real time, shedding light on the processes responsible for such changes. Meyer elaborated:
“We have very detailed observations of a radio jet ‘turning on’ in real-time, and even more exciting are the VLBI observations, which clearly show these plasma blobs moving out from the black hole. That shows us that this really is an outflow jet of plasma that’s causing the radio flare. It’s not some other process causing increased radio emission. This is a jet moving at likely 20 to 30 percent of the speed of light originating very near a black hole. That’s the exciting thing.”
Comparative Analysis of Jet Structures
While the jets being formed in this scenario are relatively diminutive compared to the giant jets previously detected from some of the most potent AGNs within the cosmos, scientists surmise that these types of jets are likely to be more commonplace throughout the Universe. While the most expansive jets can extend far beyond their host galaxies and persist over millions of years, researchers have recently become aware of smaller, transient jets—termed “compact symmetric objects” (CSOs). In this context, the jets observed in 1ES 1927+654 present a unique opportunity to gain further insights into how these structures originate and develop over time.
Researchers plan to continue monitoring 1ES 1927+654 as any tidal disruptions may indicate the ongoing presence of a white dwarf star being steadily consumed. Professor Meyer and her colleagues propose that the emergence of these jets could correlate with a solitary event involving the ingestion of a star or a gas cloud; the researchers suggest that a singular tidal disruption event may initiate the mechanisms powering short-term CSOs, lasting potentially around 1,000 years. Meyer concluded:
“We still don’t really understand, after all these decades of studying these sources, why only a fraction of accreting black holes produce jets and exactly how they launch them. Until recently, we could not literally look into that innermost region to see what’s happening—how the accretion disk surrounding the black hole is interacting with and producing the jet. And so there are still a lot of open questions there.”
Future Observational Directions
Despite the many unanswered questions, several promising models have been proposed regarding the formation and development of these jets. These groundbreaking observations may pave the way for collaborative efforts between observational astronomers and theorists to derive meaningful interpretations from this vast array of data, thus enabling the refinement of existing models. Meyer expressed optimism about future research:
“There’s a lot of theoretical work to be done to understand what we’ve seen, but the good thing is that we have a massive amount of data. We’re going to keep following this source, and it’s going to continue to be exciting.”
For More Information
For further insights into astronomical phenomena and the nature of black holes, consider referencing works published in the various journals dedicated to astrophysics and related scientific studies.
