An object initially mistaken as a galaxy was a black hole pointed directly at Earth

What was once formerly known as a radio galaxy has now been classified as a blazar.
Kavita Verma
An artistic illustration of blazar
An artistic illustration of blazar– a ferocious and highly luminous astronomical object, where the relentless feeding of a supermassive black hole creates powerful jets of radiation that shoot out towards Earth at nearly the speed of light. 

A team of international astronomers has recently discovered a galaxy that has undergone a classification change due to the unique activity within its core. The galaxy, formerly known as PBC J2333.9-2343, was reclassified as a giant radio galaxy measuring four million light-years across. This new finding was published in the Monthly Notices of the Royal Astronomical Society.

Not a radio galaxy but a blazar

According to the researchers, the galaxy, previously classified as a radio galaxy, is now classified as a blazar.

A blazar is an active galactic nucleus (AGN) with a relativistic jet, which travels at a speed close to that of light directed toward an observer. The blazar is an exceptionally high-energy object and is considered one of the most powerful phenomena in the universe.

Meanwhile, another object that was initially mistaken as a galaxy has been identified as a black hole pointed directly at Earth. This object, called SDSS J103027.09+052455.0, was identified using data from the Sloan Digital Sky Survey.

It was initially classified as a galaxy due to its bright nucleus, but observations from the Gran Telescopio Canarias in Spain revealed a black hole surrounded by a disk of gas.

What caused the categorization change? 

In PBC J2333.9-2343, the jet changed its direction by an angle of up to 90 degrees, going from being in the plane of the sky to pointing directly towards Earth. This led to the emission of radiation across the entire electromagnetic spectrum, and it caused the galaxy's categorization to change.

The astronomers used various electromagnetic spectrum observations to learn more about the mysterious galaxy. They observed PBC J2333.9-2343 with radio, optical, infrared, x-ray, ultraviolet, and gamma-ray telescopes.

The team then compared the properties of PBC J2333.9-2343 with large samples of blazars and non-blazar galaxies provided by the Automatic Learning for the Rapid Classification of Events (ALeRCE) project in Chile, along with data from the Zwicky Transient Facility (ZTF) and the Asteroid Terrestrial-impact Last Alert System (ATLAS).

In conclusion

The team concluded that the galaxy has a bright blazar in its center, with two lobes in the outer areas of the jet. These lobes are related to the old jets and are no longer being fed by the emission from the nucleus. They are relics of past radioactivity, whereas the structures closer to the nucleus represent younger and active jets.

The team does not yet know what caused the drastic change in the direction of the jets. They speculate it could have been a merging event with another galaxy, a relatively large object, or a strong burst of intense activity in the galactic nucleus after a dormant period.

Dr. Lorena Hernández-García, the paper's lead author and researcher at the Millennium Institute of Astrophysics, said:

"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. The fact that we see the nucleus is not feeding the lobes anymore means that they are very old. They are the relics of past activity, whereas the structures located closer to the nucleus represent younger and active jets."

The discovery of PBC J2333.9-2343 is significant because it highlights the possibility of reclassifying galaxies based on changes in the direction of their jets.

Add Interesting Engineering to your Google News feed.
Add Interesting Engineering to your Google News feed.
message circleSHOW COMMENT (1)chevron
Job Board