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FRBs – whence galactic epic flashes of energy?

John Healy
Supernova GRB from a magnetar
(Wiki) Image licensed under the Creative Commons Attribution 4.0 International license. Created by the European Southern Observatory (ESO), this artist’s impression shows a supernova and associated gamma-ray burst driven by a magnetar.

Epic events catch our attention. Spectacular stellar events have attracted attention since ancient times. Some events, however, cannot be observed with our eyes (visible light). Radio sources. And massive spikes in radio energy are telling astronomers something interesting.

• NASA > “Hubble Tracks Down Fast Radio Bursts to Galaxies’ Spiral Arms” (May 20,2021) [Includes YouTube video.]

(quote) Astronomers using NASA’s Hubble Space Telescope have traced the locations of five brief, powerful radio blasts to the spiral arms of five distant galaxies.

Called fast radio bursts (FRBs), these extraordinary events [can] generate as much energy in a thousandth of a second as the Sun does in a year [1]. Because these transient radio pulses disappear in much less than the blink of an eye, researchers have had a hard time tracking down where they come from, much less determining what kind of object or objects is causing them. Therefore, most of the time, astronomers don’t know exactly where to look.

The team’s Hubble results, however, are consistent with the leading model that FRBs originate from young magnetar outbursts.

Notes

[1] But no worries, as Wiki notes:

Astronomers estimate the average FRB releases as much energy in a millisecond as the sun puts out in 3 days. While extremely energetic at their source, the strength of the signal reaching Earth has been described as 1,000 times less than from a mobile phone on the Moon.

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3 thoughts on “FRBs – whence galactic epic flashes of energy?”

  1. Here’s an article about how FRBs are used to study our galactic halo, based on galaxy-formation simulations (models). Are magnetars the only source?

    • Caltech > News > “Cosmic Burst Probes Milky Way’s Halo” by Whitney Clavin (January 09, 2023) – Of the several hundreds of FRBs discovered to date, only 21 have been pinpointed to known galaxies.

    (quote) The latest findings, submitted to The Astrophysical Journal, are part of a bevy of new results from Caltech’s Deep Synoptic Array (DSA) [which began commissioning in February 2022], a National Science Foundation (NSF)-funded collection of radio dishes located in the high desert at Owens Valley Radio Observatory, east of California’s Sierra Nevada mountains.

    The scientists studied the way that the light of the so-called fast radio burst, or FRB, was dispersed as it traveled from deep space and into our galaxy as a means to estimate how much matter resides in the galaxy’s halo. This is a bit like shining a flashlight through fog to see how thick the cloud is; the more matter there is, the more the light will disperse.

    The results … [support] theories that say matter is regularly flung out of galaxies by powerful stellar winds, exploding stars, and actively feeding, or accreting, supermassive black holes.

    FRB into halo visualization

  2. Here’s an article about a study which used X-ray data from the European Space Agency’s X-ray Multi-Mirror Mission (XMM-Newton) and NASA’s Neutron Star Interior Composition Explorer (NICER).

    And standard physics models of angular momentum and conservation of energy. And magnetic fields.

    “Magnetars emit intense radiation, including X-rays and occasional radio waves and gamma rays.” Even fast radio bursts.

    • Phys.org > “Volcano-like rupture could have caused magnetar slowdown” by Jade Boyd, Rice University (January 27, 2023) – a new theory about a possible cause for the rare rotational slowdown of a magnetar – a surface vs. interior change.

    (quote) On Oct. 5, 2020, the rapidly rotating corpse of a long-dead star about 30,000 light years from Earth changed speeds. In a cosmic instant, its spinning slowed. And a few days later, it abruptly started emitting radio waves

    “People have speculated that neutron stars could have the equivalent of volcanoes on their surface,” said Baring, a professor of physics and astronomy. “Our findings suggest that could be the case and that on this occasion, the rupture was most likely at or near the star’s magnetic pole.”

    Magnetar eruption
    An artist’s impression of a magnetar eruption. Credit: NASA’s Goddard Space Flight Center

  3. FRB viz

    Active research on FRBs (fast radio bursts) continues. “… questions linger about the nature of FRBs, including why a handful seem to go off multiple times a day while others flash only once.”

    • Space.com > “Where do fast radio bursts come from? Astronomers tie mysterious eruptions to massive galaxies” by Sharmila Kuthunur (November 9, 2024) – Are FRBs linked to the formation of magnetars?

    Now, astronomers led by Kritti Sharma at the California Institute of Technology …

    By analyzing the home galaxies of 30 FRBs recorded by California’s Deep Synoptic Array-110, Sharma and her colleagues found that the bursts originated in massive, star-forming galaxies rich in “metals” — astronomer-speak for any element heavier than hydrogen and helium. Such metal-rich environments may be conducive to the formation of magnetars, which are the leading candidates for producing FRBs, according to the researchers.

    Metal-rich stars that reside in pairs in such galaxies tend to become less compact as they evolve, accelerating the transfer of mass between them and effectively initiating the timeline for a stellar merger, the researchers say. The surviving star, usually the larger of the two, is rejuvenated by burning the fuel accreted from its companion, leading to amplified magnetic fields that are hundreds of trillions of times stronger than Earth’s — a magnetar.

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