Changing-look events observed in the galaxy NGC 5273

Tomasz Nowakowski is a member of the physics.org community.

Astronomers have looked at new and old observations of the active galaxies. There were so-called "changing-look" events in the active galactic nucleus. There is a paper on arXiv.org.

An AGN is a small area at the center of a galaxy that is brighter than the surrounding light. They are very energetic due to the presence of a black hole.

The emission line features are used to divide AGNs into two groups. Broad and narrow emission lines can be seen in type 1 AGNs, while only narrow emission lines can be seen in type 2 AGNs. Some AGNs were dubbed changing-look AGNs due to the fact that they transitioned between different types.

There is a low-luminosity variable in the AGN of NGC 5273. The nucleus of the AGN is not as bright as other ones. The galaxy began to increase in brightness in the late 21st century.

Jack M.M. Neustadt is an astronomer at the Ohio State University. The finding is the result of a detailed analysis of a huge amount of data obtained by various telescopes.

According to the study conducted by Neustadt's team, there was at least one changing look event. The active galactic nucleus of NGC 5273 is one of the few AGNs known to change-look in the IR.

There is evidence for historical variability prior to 2000 and a flare of AGN in the year 2014). The other flares may have been temporary changing-look events from a baselineType 1.8/1.9 intoType 1

There have been short flares in 2002 and 2016 and a long flare that started in late 2021.

The researchers concluded that the changing look events are likely due to changes in how the broad line region reprocesses the emission continuum.

The Balmer decrement or the NIR broad lines could be affected by changes in the wind.

There is more information about Once is an Instance, Twice is a Hobby. There is a book titled "arxiv.2211.03801."

Journal information: arXiv

There is a science network.

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