(ORDO NEWS) — We don’t know what the RAD12-B galaxy did, but it must have been something terrible.
This is because its neighboring galaxy has fired a jet of hot plasma directly at it in what seems (if we’re going to be anthropomorphic) like a targeted attack.
Discovered by a team led by astronomer Ananda Hota. from the University of Mumbai in India, this is the sixth pair of galaxies involved in this kind of plasma explosion.
But the RAD12 system is unique for several reasons, and astronomers don’t know why.
First, for the first time, we are seeing a galaxy firing a plasma torch at a larger galaxy. There is.
For the other, there is only one jet. We have seen many, many galaxies throwing plasma jets into space, and usually these jets come in pairs. Why RAD12 only has one remains a mystery.
High-speed plasma jets emitting radiation in the radio range are quite common in the Universe.
They are known as radio galaxies, and the jets are emitted from the galactic core. Scientists believe that the supermassive black hole at the center of the galaxy is to blame.
Galactic supermassive black holes are often surrounded by a huge amount of material that rotates in the disk and falls onto the black hole from the inside of the disk.
However, this accretion process is erratic; not all material from the inner edge of the disk goes beyond the event horizon.
Some of them are deflected and accelerated along the magnetic field lines around the black hole.
It is carried to the black hole’s poles, where it is launched into space at close to the speed of light in a vacuum, traversing vast distances through the intergalactic medium, acting as a synchrotron to accelerate electrons, which then emit radio waves.
We still don’t understand much about this process, but it’s commonly seen in elliptical galaxies, which are fuzzy, shapeless blobs, as opposed to the highly structured forms of spiral galaxies.
In elliptical galaxies, as a rule, there is not much star formation; most of the stars inside them are old, and they don’t contain as much star-forming material.
The jets are thought to play a role in this by providing “feedback” that suppresses star formation.
The RAD12 system can help astronomers understand these processes, as outliers place limits on what certain classes of objects can and cannot do.
In addition, rare galactic systems in which one jet collides with another may exhibit positive feedback, in which the bombarded galaxy shows signs of positive feedback or increased star formation activity.
Scientists know. that there was something unusual about RAD12, located about a billion light-years away, since the 1990s, but this was not the case until a citizen science project to analyze data collected by the Giant Meter Wave Radio Telescope (GMRT) in India , called [email protected ], which revealed all of its strangeness.
An optical image of the Legacy Survey showing the “shells” of the stars. (Hota et al., arXiv, 2023)
Two galaxies in the system are in the process of merging, their two cores separated by 414,000 light years.
Together, the entire structure is 440,000 light-years long, much larger than the jet’s host galaxy (although it is not unusual for a radio jet to be longer than the diameter of the host galaxy).
This means that the jet is crashing into RAD12-B, but unlike five other galactic systems of its type, RAD12-B does not show signs of positive feedback, i.e. increased star formation activity.
And the single jet of the parent galaxy is a real puzzle.
It is possible that something could have prevented its escape, such as the “shells” of stars around the galaxy created by a past merger that engulfed the interstellar medium and led to regions of higher density.
We have also seen cases where radio jets have been bent and deflected by powerful magnetic fields in space.
Figuring out what exactly is going on with RAD12 will require more work, including observations with multiple telescopes, but it promises to be a truly exciting case.
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