Spinning black hole powers jet by magnetic flux

Date:
August 21, 2020
Source:
University of Wu"rzburg
Summary:
A new letter has been found in the mysterious alphabet of black
holes.



FULL STORY ========================================================================== Black holes are at the center of almost all galaxies that have been
studied so far. They have an unimaginably large mass and therefore
attract matter, gas and even light. But they can also emit matter in
the form of plasma jets -- a kind of plasma beam that is ejected from
the centre of the galaxy with tremendous energy. A plasma jet can extend several hundred thousand light years far into space.


==========================================================================
When this intense radiation is emitted, the black hole remains hidden
because the light rays near it are strongly bent leading to the appearance
of a shadow.

This was recently reported by researchers of the Event Horizon Telescope
(EHT) collaboration for the massive black hole in the giant ellipse
galaxy M87.

In quasar 3C279 -- also a black hole -- the EHT team found another
phenomenon: At a distance of more than a thousand times the shadow of
the black hole, the core of a plasma jet suddenly lit up. How the energy
for this jet could get there as if through an invisible chimney was not
yet known.

Extremely flickering gamma radiation detected This quasar has
now been observed with the NASA space telescope Fermi-LAT by the
astrophysicist Amit Shukla, who until 2018 did research at Julius- Maximilians-Universita"t (JMU) Wu"rzburg in Bavaria, Germany. He now is
working at the Indian Institute of Technology in Indore. Shukla discovered
that the core of the jet, which was found in the millimeter wavelength
range, also emits high-energy gamma radiation, but with an extremely
flickering brightness. This brightness can double within a few minutes,
as reported in the journal Nature Communications.

The special pattern of the sequence of brightness changes is
characteristic of a universal process called magnetic reconnection,
which occurs in many astrophysical objects with strong magnetic
fields. Solar activity also has to do with the dynamics of magnetic
fields and reconnection. This was recently demonstrated by observing "campfires" in the solar atmosphere with the "Solar Orbiter" mission of
the European Space Agency ESA.

Invisibly stored energy is suddenly released But back to the quasar 3C279:
"I saw how the analysis of the data revealed the special pattern of
magnetic reconnection in the light curve. It felt as if I had suddenly deciphered a hieroglyph in the black hole alphabet," says Amit Shukla
happily.

During reconnection, energy that is initially stored invisibly in the
magnetic field is suddenly released in numerous "mini-jets." In these
jets, particles are accelerated, which then produce the observed gamma radiation. Magnetic reconnection would explain how the energy reaches
the jet's core from the black hole and where it ultimately comes from.

Energy from the spinning black hole Professor Karl Mannheim, head of
the JMU Chair of Astronomy and co-author of the publication, explains: "Spacetime near the black hole in the quasar 3C279 is forced to swirl
around in corotation. Magnetic fields anchored to the plasma around
the black hole expel the jet slowing down the black hole's rotation and converting part of its rotational energy into radiation."

========================================================================== Story Source: Materials provided by University_of_Wu"rzburg. Original
written by Robert Emmerich. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. A. Shukla, K. Mannheim. Gamma-ray flares from relativistic magnetic
reconnection in the jet of the quasar 3C 279. Nature Communications,
2020; 11 (1) DOI: 10.1038/s41467-020-17912-z ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200821103858.htm

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