According to new study, an object that was once believed to be a radio
galaxy is actually an active black hole that changed angles to aim straight
at Earth.
Scientists are baffled by a supermassive black hole in a far-off galaxy
that has suddenly turned sharply 90 degrees to face straight toward Earth
while spewing radiation at close to light speed.
The ravenous black holes at the centers of many other galaxies are known as
active galactic nuclei (AGN), which accrete matter and release potent
relativistic streams of high-energy particles. AGN are categorized based on
the portion that is aimed at Earth.
PBC J2333.9-2343, a massive galaxy with a diameter of 4 million
light-years, was originally categorized as a radio galaxy, which meant that
the enormous jets of radiation coming from its AGN were directed away from
Earth. However, recent study redesignates the galaxy as a blazar, meaning
the black hole's jets are now directed directly at Earth. This new
classification was made public on March 20 in the journal
Monthly Notices of the Royal Astronomical Society. This indicates a "dramatic" degree of change in the galaxy's jets,
according to the study's authors.
According to lead
study
author
Lorena Hernández-Garca, an astrophysicist at the Millennium Institute of Astrophysics, "Our
hypothesis was that the relativistic jet of its supermassive black hole had
changed its direction, and to confirm that idea we had to carry out a lot of
observations."
From radio waves to gamma rays, Hernández-Garca and coworkers witnessed PBC
J2333.9-2343 over almost the complete electromagnetic spectrum. Their
studies revealed that this galaxy exhibited blazar-like traits, including
comparable jets and brightening and dimming patterns. So, they came to the
conclusion that the item was probably a blazar.
The researchers also noticed two lobes, where some jets had earlier left
their imprint and where an AGN's jets engage with the nearby gas. The lobes
of this blazar, according to Hernández-Garca, are "very old," and "they are
the remnants of past activity, in contrast to the structures located closer
to the nucleus, which represent younger and active jets."
These inactive lobes are proof that the aircraft have indeed altered
course. The appearance of a galaxy's rockets in various locations is not
entirely unusual. However, in earlier instances, there were two pairs of
lobes, which meant that two distinct jets were going on and off. There
appears to be only one source of action for PBC J2333.9-2343, and that
source has altered its strategy.
What led to this significant shift? That is still being worked out by
astronomers. According to current hypotheses, PBC J2333.9-2343 and another
big galaxy collided, causing everything inside it to move around and undergo
a galactic merger. For this riddle to be solved, more data are
required.
