Astronomers Track Jet Launch, Fluctuating X-Rays from Brink of Active Black Hole

  • Released Monday, January 13, 2025
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Active galaxy 1ES 1927+654, circled, has exhibited extraordinary changes since 2018, when a major outburst occurred in visible, ultraviolet, and X-ray light. The galaxy harbors a central black hole weighing about 1.4 million solar masses and is located 270 million light-years away.Credit: Pan-STARRSUnannotated versions available.Image description: On a mottled black background, soft circles ranging in color from blue-white to orange represent stars in our own galaxy. At center, to the right of a chain of three bluish stars, lies a softer white circle set within a grayish ellipse whose longest dimension is oriented vertically. This is 1ES 1927+654, circled in green in this image.

Active galaxy 1ES 1927+654, circled, has exhibited extraordinary changes since 2018, when a major outburst occurred in visible, ultraviolet, and X-ray light. The galaxy harbors a central black hole weighing about 1.4 million solar masses and is located 270 million light-years away.

Credit: Pan-STARRS

Unannotated versions available.

Image description: On a mottled black background, soft circles ranging in color from blue-white to orange represent stars in our own galaxy. At center, to the right of a chain of three bluish stars, lies a softer white circle set within a grayish ellipse whose longest dimension is oriented vertically. This is 1ES 1927+654, circled in green in this image.

International teams of astronomers monitoring a supermassive black hole in the heart of a distant galaxy have detected features never seen before using data from NASA missions and other facilities. The features include the launch of a plasma jet moving at nearly one-third the speed of light and unusual, rapid X-ray fluctuations likely arising from near the very edge of the black hole.

The source is 1ES 1927+654, a galaxy located about 270 million light-years away in the constellation Draco. It holds a central black hole with a mass equivalent to about 1.4 million Suns. In 2018, the black hole began changing its properties with a major optical, ultraviolet, and X-ray outburst, and astronomers have been closely watching it ever since.

After the outburst, the black hole appeared to settle down, with a lull in activity for nearly a year. But by April 2023, a months-long increase in low-energy X-rays triggered interest in new radio observations, which indicated a strong and highly unusual radio flare was underway. The scientists then began intensive observations using the NRAO’s (National Radio Astronomy Observatory) VLBA (Very Long Baseline Array), a network of radio telescopes spread across the U.S. whose signals can be combined to create what amounts to a powerful, high-resolution radio camera. This allows the VLBA to detect features less than a light-year across at 1ES 1927+654’s distance.

Radio data from February, April, and May 2024 reveals what appear to be jets of ionized gas, or plasma, extending from either side of the black hole, with a total size of about half a light-year. The launch of a black hole jet has never been observed before in real time.

Observations by ESA's (European Space Agency) XMM-Newton mission found that the black hole exhibited extremely rapid X-ray variations between July 2022 and March 2024. During this period, the X-ray brightness repeatedly rose and fell by 10% every few minutes. Such changes, called millihertz quasiperiodic oscillations, are difficult to detect around supermassive black holes and have been observed in only a handful of systems to date.

One way to produce these oscillations is with an object orbiting within the black hole’s accretion disk. In this scenario, each rise and fall of the X-rays represents one orbital cycle. If true, then the period would shorten as the object fell ever closer to the black hole’s event horizon, the point of no return. Orbiting masses generate ripples in space-time called gravitational waves. These waves drain away orbital energy, bringing the object closer to the black hole, increasing its speed, and shortening its orbital period.

Over two years, the fluctuation period dropped from 18 minutes to just 7 — the first ever measurement of its kind around a supermassive black hole. If this represented an orbiting object, it was now moving at half the speed of light. Then something unexpected happened — the fluctuation period stabilized.

Astronomers determined that this was possible if the orbiting object had fallen close enough to the black hole that tidal forces had begun stripping material from it. This could offset the orbital energy drained away by gravitational waves, stalling the object's inward motion. The best candidate for this object, they found, is a white dwarf — a stellar remnant about Earth's size.

If such a companion does exist, it's producing gravitational waves that will be detectable by LISA (Laser Interferometer Space Antenna), an ESA mission in partnership with NASA that is expected to launch in the next decade.

Radio images of 1ES 1927+654 reveal emerging structures that appear to be jets of plasma erupting from both sides of the galaxy’s central black hole following a strong radio flare. The first image, taken in June 2023, shows no sign of the jet, likely because hot gas screened it from view. Then, starting in February 2024, the features emerge and expand away from the galaxy’s center, covering a total distance of about half a light-year as measured from the center of each structure. Credit: NSF/AUI/NSF NRAO/Meyer at al. 2025An unlabeled version is available, as is an alternate version that includes radio contours and beam shape.Image description: On a navy blue and purple background, two orange and yellow shapes appear and move away from the center of the frame. The shapes show radio emission from a newly formed jet of ionized gas launched by the galaxy's supermassive black hole. The shapes are absent in the first frame, which is dated "2023-06-08" at upper left, but they appear and move apart in subsequent images labeled "2024-02-09," "2024-04-24," and "2024-05-30." At lower right, a scale bar illustrates the extent of the features with the labels "0.2 parsecs" on top and "0.65 light-years" below. The graphic is bordered by a thin white line.

Radio images of 1ES 1927+654 reveal emerging structures that appear to be jets of plasma erupting from both sides of the galaxy’s central black hole following a strong radio flare. The first image, taken in June 2023, shows no sign of the jet, likely because hot gas screened it from view. Then, starting in February 2024, the features emerge and expand away from the galaxy’s center, covering a total distance of about half a light-year as measured from the center of each structure.

Credit: NSF/AUI/NSF NRAO/Meyer at al. 2025

An unlabeled version is available, as is an alternate version that includes radio contours and beam shape.

Image description: On a navy blue and purple background, two orange and yellow shapes appear and move away from the center of the frame. The shapes show radio emission from a newly formed jet of ionized gas launched by the galaxy's supermassive black hole. The shapes are absent in the first frame, which is dated "2023-06-08" at upper left, but they appear and move apart in subsequent images labeled "2024-02-09," "2024-04-24," and "2024-05-30." At lower right, a scale bar illustrates the extent of the features with the labels "0.2 parsecs" on top and "0.65 light-years" below. The graphic is bordered by a thin white line.

In this artist’s concept, matter is stripped from a white dwarf (sphere at lower right) orbiting within the innermost accretion disk surrounding 1ES 1927+654’s supermassive black hole. Astronomers developed this scenario to explain the evolution of rapid X-ray oscillations detected by ESA’s (European Space Agency) XMM-Newton satellite. ESA’s LISA (Laser Interferometer Space Antenna) mission, due to launch in the next decade, should be able to confirm the presence of an orbiting white dwarf by detecting the gravitational waves it produces. Credit: NASA/Aurore Simonnet, Sonoma State University Image description: Swirls of color ranging from orange, yellow, and white to various shades of teal, surround a black oval representing a supermassive black hole. The oval and the colored region around it tilt so that the right side is higher than the left. Half of a teal ellipse extends vertically above the oval and reperesents the black hole's X-ray-emitting corona. A conical shape, faintly outlined in teal and by small, irregular white shapes, also extends away from the black hole; it represents the start of a jet of ionized gas. Below the black hole, a white dwarf orbits within the brightly colored region representing the accretion disk. It trails a stream of reddish white debris. In the blue-black background, a smattering of distant stars can be seen.

In this artist’s concept, matter is stripped from a white dwarf (sphere at lower right) orbiting within the innermost accretion disk surrounding 1ES 1927+654’s supermassive black hole. Astronomers developed this scenario to explain the evolution of rapid X-ray oscillations detected by ESA’s (European Space Agency) XMM-Newton satellite. ESA’s LISA (Laser Interferometer Space Antenna) mission, due to launch in the next decade, should be able to confirm the presence of an orbiting white dwarf by detecting the gravitational waves it produces.

Credit: NASA/Aurore Simonnet, Sonoma State University

Image description: Swirls of color ranging from orange, yellow, and white to various shades of teal, surround a black oval representing a supermassive black hole. The oval and the colored region around it tilt so that the right side is higher than the left. Half of a teal ellipse extends vertically above the oval and reperesents the black hole's X-ray-emitting corona. A conical shape, faintly outlined in teal and by small, irregular white shapes, also extends away from the black hole; it represents the start of a jet of ionized gas. Below the black hole, a white dwarf orbits within the brightly colored region representing the accretion disk. It trails a stream of reddish white debris. In the blue-black background, a smattering of distant stars can be seen.

A possible alternative explanation for the rapid X-ray fluctuations observed in 1ES 1927+654 involves oscillations of the black hole's corona, which may be related to the base of the jet. Exactly what would drive this behavior is unknown at present. In this artist's concept, the corona/jet base (blue ellipse/surrounding conical area) rhythmically expand and contract.Credit: NASA/Aurore Simonnet, Sonoma State UniversityImage description: Swirls of color ranging from orange, yellow, and white to various shades of teal, surround a black oval representing a supermassive black hole. The oval and the colored region around it tilt so that the right side is higher than the left. Half of a teal ellipse extends vertically above the oval and reperesents the black hole's X-ray-emitting corona. A conical shape, faintly outlined in teal and by small, irregular white shapes, also extends away from the black hole; it represents the start of a jet of ionized gas. The corona and the jet base expand and contract laterally at regular intervals. In the blue-black background, a smattering of distant stars can be seen.

A possible alternative explanation for the rapid X-ray fluctuations observed in 1ES 1927+654 involves oscillations of the black hole's corona, which may be related to the base of the jet. Exactly what would drive this behavior is unknown at present. In this artist's concept, the corona/jet base (blue ellipse/surrounding conical area) rhythmically expand and contract.

Credit: NASA/Aurore Simonnet, Sonoma State University

Image description: Swirls of color ranging from orange, yellow, and white to various shades of teal, surround a black oval representing a supermassive black hole. The oval and the colored region around it tilt so that the right side is higher than the left. Half of a teal ellipse extends vertically above the oval and reperesents the black hole's X-ray-emitting corona. A conical shape, faintly outlined in teal and by small, irregular white shapes, also extends away from the black hole; it represents the start of a jet of ionized gas. The corona and the jet base expand and contract laterally at regular intervals. In the blue-black background, a smattering of distant stars can be seen.

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This page was originally published on Monday, January 13, 2025.
This page was last updated on Monday, January 13, 2025 at 2:37 PM EST.

Related papers

Late-time radio brightening and emergence of a radio jet in the changing-look AGN 1ES 1927+654
Millihertz Oscillations Near the Innermost Orbit of a Supermassive Black Hole
Multi-wavelength observations of a jet launch in real time from the post-changing-look Active Galaxy 1ES 1927+654