Imagine a cosmic leviathan, dormant for eons, suddenly roaring to life, not just once, but repeatedly, defying everything scientists thought they knew about its behavior. That’s the extraordinary tale unfolding with a supermassive black hole, 1ES 1927+654, nestled 270 million light-years away in the constellation Draco. This colossal black hole, a staggering 1.4 million times the mass of our Sun, has utterly reshaped our understanding of these mysterious objects. It’s not just that it’s active; it’s the sheer unpredictability of its actions—launching a plasma jet at nearly a third the speed of light and flickering with strange X-ray signals right at its edge—that has astronomers scratching their heads.
For decades, the leading idea about active black holes—the “Active Galactic Nuclei (AGN) unification framework”—suggested their appearance largely depended on our viewing angle, with any changes unfolding over millions of years. But 1ES 1927+654 has thrown a cosmic curveball, drastically altering its appearance and unleashing intense radiation in mere weeks or months. This black hole first stirred in 2018 with a massive eruption of light across various wavelengths. After a period of calm, it shocked astronomers again in April 2023, igniting a powerful radio flare that has stubbornly remained elevated for over a year, 60 times brighter than before.
A Powerful Jet Emerges from the Darkness
The most astonishing discovery is the sudden appearance of a brand-new, powerful outflow of superheated gas, a “jet,” blasting from the black hole. Before 2023, radio observations showed almost nothing notable. Now, advanced telescopes reveal distinct structures extending from the black hole’s core, a clear sign of a young, high-speed jet. The fact that this jet emerged years after the initial fireworks, and continues to blast material, challenges current thinking about how these jets form and grow. It’s like a volcano that erupts years after the earthquake that triggered it, and then keeps spewing lava. This delayed radio activity is a puzzling, though increasingly observed, pattern in certain “changing-look” black holes and events where stars are ripped apart by black holes.
This powerful radio jet, appearing years after the initial outburst, is a profound discovery. It runs counter to the conventional wisdom that these jets form rapidly during the most violent phases of a black hole’s activity. The radio signals from 1ES 1927+654 resemble “gigahertz-peaked radio sources,” which are known to be young jets, typically less than a thousand years old. This observation strengthens the idea that the jet is indeed newly formed. The simultaneous increase in soft X-ray emissions, alongside the radio flare, hints that this X-ray activity might be related to gas heated by the expanding jet.
How Scientists Tracked This Cosmic Enigma
To unravel these astonishing developments, a global team of astronomers employed a vast network of observatories. The core information for this study came from various radio telescopes, including the Very Long Baseline Array (VLBA), the European VLBI Network (EVN), the Very Large Array (VLA), and others. This diverse collection allowed researchers to scrutinize the black hole across a wide range of radio frequencies and with incredible detail.
The story of this black hole’s awakening began in late 2017 with an optical outburst, where its light rapidly brightened by a factor of 100. Initially, the X-ray emissions from the black hole were wildly erratic. At one point in 2018, the hard X-ray emission—thought to come from a superheated cloud of gas around the black hole—completely vanished for about three months. Then, it flared up dramatically, becoming a thousand times brighter and exceeding the theoretical limit for a black hole of its size, a state it maintained for over a year before returning to its previous levels. These swift X-ray changes were unlike what’s typically seen in tidal disruption events, where a star is torn apart by a black hole’s gravity.
The current study particularly focused on the radio emission, which had remained relatively quiet for years after the initial optical and X-ray drama. However, a steady rise in soft X-ray emissions, spotted by NASA’s Swift Observatory, prompted a swift decision for urgent observations with the VLBA in April 2023. This quick action led to the discovery of the dramatic radio flare, where the radio brightness surged by a factor of 7. Observations continued relentlessly, with data collected regularly from April 2023 through May 2024, and monitoring is still ongoing.
A crucial breakthrough came from the high-resolution VLBA observations in July 2023. These allowed astronomers to clearly see the new jet structure, revealing two distinct extensions on either side of the black hole’s core, separated by about half a light-year. The comprehensive and continuous monitoring across multiple observatories provides a rich, multi-dimensional dataset, offering an unprecedented look at the black hole’s dynamic behavior. The long history of observations, stretching back to 2013, allowed them to trace the black hole’s evolution from a “radio-quiet” state to its current “radio-bright” state with a newly launched jet.
Redefining Black Hole Behavior
The findings from 1ES 1927+654 compel us to rethink the fundamental processes governing supermassive black holes. These aren’t just immense gravitational vacuum cleaners; they are incredibly active and dynamic systems, capable of surprising transformations on timescales we can actually observe. The universe continues to unveil its mysteries, challenging our assumptions and pushing the boundaries of scientific inquiry. The ongoing study of this unique black hole will undoubtedly provide more clues, potentially leading to a new understanding of these enigmatic cosmic giants.
Paper Summary
Methodology
This study involved extensive, long-term radio observations of the changing-look active galactic nucleus (CL-AGN) 1ES 1927+654, primarily using the Very Long Baseline Array (VLBA) and the European VLBI Network (EVN). Additional data came from the Very Large Array (VLA), Arcminute Microkelvin Imager (AMI), e-MERLIN, and the Submillimeter Array (SMA). Observations were conducted across multiple radio frequencies (5-345 GHz) and resolutions, from 2013 through May 2024, with intensified monitoring starting in April 2023.
Results
The research identified a significant radio flare in 1ES 1927+654, beginning in February 2023, which reached 60 times its previous brightness and remained elevated. Crucially, high-resolution VLBA observations confirmed the emergence of a new, high-speed radio jet with resolved structures extending from the black hole’s core. The jet’s radio characteristics suggest it is young, likely less than a thousand years old. This late-time jet emergence, years after the initial optical/X-ray outburst, challenges current models of black hole jet formation.
Limitations
The paper indicates that while the observed soft X-ray increase might relate to jet-driven gas, more observations are needed to confirm this. As the study focuses on a single, unusual object, its findings may not be immediately applicable to all changing-look AGNs. This is an initial publication, implying ongoing research.
Funding and Disclosures
The paper is open access, allowing free use with attribution. One author holds a “Neil Gehrels Fellow” position. Authors are affiliated with various universities and research institutions, including the University of Maryland Baltimore County, NASA Goddard Space Flight Center, Space Telescope Science Institute, University of Oxford, MIT, and Harvard & Smithsonian, among others.
Publication Information
The paper is titled “Late-time Radio Brightening and Emergence of a Radio Jet in the Changing-look AGN 1ES 1927+654”. It was published in The Astrophysical Journal Letters, Volume 979, Number L2, on January 20, 2025. The Digital Object Identifier (DOI) is https://doi.org/10.3847/2041-8213/ad8651.
The post Astronomers Stunned: Black Hole’s Sudden Outburst Rewrites Rulebook appeared first on SpaceChatter.