Spontaneous Magnetic Reversal of Monster Black Hole Sparks Enigmatic Outburst

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Accretion Disk, Corona, and Supermassive Black Hole of Active Galaxy

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This illustration reveals the accretion disk, corona (pale, conical swirls above the disk), and supermassive black gap of lively galaxy 1ES 1927+654 earlier than its latest flare-up. Credit: NASA/Sonoma State University, Aurore Simonnet

NASA’s Swift Observatory Tracks Potential Magnetic Flip of Monster Black Hole

A uncommon and enigmatic outburst from an lively galaxy 236 million light-years away might have been sparked by a magnetic reversal, a spontaneous flip of the magnetic discipline surrounding its central black hole.

In a comprehensive new study, an international team of scientists links the eruption’s unusual characteristics to changes in the black hole’s environment that likely would be triggered by such a magnetic switch.

Explore the weird eruption of 1ES 1927+654, a galaxy situated 236 million light-years away within the constellation Draco. A sudden reversal of the magnetic discipline round its million-solar-mass black gap might have triggered the outburst. Credit: NASA’s Goddard Space Flight Center

“Rapid changes in visible and ultraviolet light have been seen in a few dozen galaxies similar to this one,” said Sibasish Laha, a research scientist at the University of Maryland, Baltimore County and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “But this event marks the first time we’ve seen X-rays dropping out completely while the other wavelengths brighten.”

A paper describing the findings, led by Laha, is accepted for publication in The Astrophysical Journal.

This sequence illustrates numerous options of galaxy 1ES 1927+654’s outburst, from its dramatically elevated brightness in seen and UV to the loss and restoration of the corona, the supply of high-energy X-rays. Credit: NASA’s Goddard Space Flight Center

The analysis crew analyzed new and archival observations throughout the spectrum. NASA’s Neil Gehrels Swift Observatory and ESA’s (European Space Agency) XMM-Newton satellite tv for pc supplied UV and X-ray measurements. Visible gentle observations got here from Italy’s 3.6-meter Galileo National Telescope and the 10.4-meter Gran Telescopio Canarias, each situated on the island of La Palma within the Canary Islands, Spain. Radio measurements have been acquired from the Very Long Baseline Array, a community of 10 radio telescopes situated throughout the United States; the Very Large Array in New Mexico; and the European VLBI Network.

In early March 2018, the All-Sky Automated Survey for Supernovae alerted astronomers {that a} galaxy referred to as 1ES 1927+654 had brightened by almost 100 instances in seen gentle. A seek for earlier detections by the NASA-funded Asteroid Terrestrial-impact Last Alert System confirmed that the eruption had begun months earlier, on the finish of 2017.

Magnetic Reversal Interpretation of the Eruption at the Center of an Active Galaxy

This diagram illustrates the magnetic reversal interpretation of the eruption on the heart of the lively galaxy often known as 1ES 1927+654. Yellow strains depict the preliminary path of the magnetic discipline, whereas orange strains point out the reversed polarity. In late December 2017, the accretion disk brightened up by to 100 instances in seen gentle, a results of elevated “feeding” by the supermassive black gap – probably triggered by a change of magnetic polarity within the outer disk. In August 2018, the reversed magnetic flux reached the inside accretion disk, inflicting the corona – and the high-energy X-rays it produced – to fade. In October 2018, the X-rays returned, indicating that the corona had been rebuilt, nevertheless it step by step grew to become extra intense, reaching a peak in November 2019. During this era, the magnetic discipline strengthened in its new orientation, and the next circulate of matter may attain the black gap. Present day: The black gap has settled into its 2011 pre-eruption state, however with a magnetic discipline of reverse polarity. Credit: NASA’s Goddard Space Flight Center/Jay Friedlander

When Swift first examined the galaxy in May 2018, its UV emission was elevated by 12 instances however steadily declining, indicating an earlier unobserved peak. Then, in June, the galaxy’s higher-energy X-ray emission disappeared.

“It was very exciting to delve into this galaxy’s strange explosive episode and try to understand the possible physical processes at work,” mentioned José Acosta-Pulido, a co-author on the Canary Islands Institute of Astrophysics (IAC) on Tenerife.

This video illustrates the magnetic reversal interpretation of the eruption on the heart of the lively galaxy often known as 1ES 1927+654, as proven within the diagram above. Credit: NASA’s Goddard Space Flight Center/Jay Friedlander

Most huge galaxies, together with our personal Milky Way, host a supermassive black hole weighing millions to billions of times the Sun’s mass. When matter falls toward one, it first collects into a vast, flattened structure called an accretion disk. As the material slowly swirls inward, it heats up and emits visible, UV, and lower-energy X-ray light. Near the black hole, a cloud of extremely hot particles – called the corona – produces higher-energy X-rays. The brightness of these emissions depends on how much material streams toward the black hole.

“An earlier interpretation of the eruption suggested that it was triggered by a star that passed so close to the black hole it was torn apart, disrupting the flow of gas,” said co-author Josefa Becerra González, also at the IAC. “We show that such an event would fade out more rapidly than this outburst.”

Neil Gehrels Swift Observatory

Illustration of the Neil Gehrels Swift Observatory. Credit: NASA

The unique disappearance of the X-ray emission provides astronomers with an important clue. They suspect the black hole’s magnetic field creates and sustains the corona, so any magnetic change could impact its X-ray properties.

“A magnetic reversal, where the north pole becomes south and vice versa, seems to best fit the observations,” said co-author Mitchell Begelman, a professor in the department of astrophysical and planetary sciences at the University of Colorado Boulder. He and his Boulder colleagues, post-doctoral researcher and co-author Nicolas Scepi and professor Jason Dexter, developed the magnetic model. “The field initially weakens at the outskirts of the accretion disk, leading to greater heating and brightening in visible and UV light,” he explained.

As the flip progresses, the field becomes so weak that it can no longer support the corona – the X-ray emission vanishes. The magnetic field then gradually strengthens in its new orientation. In October 2018, about 4 months after they disappeared, the X-rays came back, indicating that the corona had been fully restored. By summer 2021, the galaxy had completely returned to its pre-eruption state.

Magnetic reversals are likely to be common events in the cosmos. The geologic record shows that Earth’s field flips unpredictably, averaging a few reversals every million years in the recent past. The Sun, by contrast, undergoes a magnetic reversal as part of its normal cycle of activity, switching north and south poles roughly every 11 years.

Reference: “A radio, optical, UV and X-ray view of the enigmatic changing look Active Galactic Nucleus 1ES~1927+654 from its pre- to post-flare states” by Sibasish Laha (NASA-GSFC), Eileen Meyer, Agniva Roychowdhury, Josefa Becerra González, J. A. Acosta-Pulido, Aditya Thapa, Ritesh Ghosh, Ehud Behar, Luigi C. Gallo, Gerard A. Kriss, Francesca Panessa, Stefano Bianchi, Fabio La Franca, Nicolas Scepi, Mitchell C. Begelman, Anna Lia Longinotti, Elisabeta Lusso, Samantha Oates, Matt Nicholl and S. Bradley Cenko, Accepted, The Astrophysical Journal.
arXiv:2203.07446

Goddard manages the Swift mission in collaboration with Penn State, the Los Alamos National Laboratory in New Mexico, and Northrop Grumman Space Systems in Dulles, Virginia. Other partners include the University of Leicester and Mullard Space Science Laboratory in the United Kingdom, Brera Observatory in Italy, and the Italian Space Agency.