This image from the Hubble Space Telescope shows MCG-01-24-014. It is a spiral galaxy with an active galactic nucleus located 275 million light-years away and is classified as a Type 2 Seyfert galaxy. Seyfert galaxies are often closer to Earth than quasars and are distinguished by their unique spectra, especially the “forbidden” emission of type 2 Seyferts.Credit: ESA/Hubble & NASA, C. Kilpatrick
this swirl hubble space telescope This image shows a bright spiral galaxy known as MCG-01-24-014, located about 275 million light-years from Earth. MCG-01-24-014 is called an active galaxy because, in addition to being a well-defined spiral galaxy, it has a very energetic core known as an active galactic nucleus (AGN) .
More specifically, it is classified as a Type 2 Seyfert galaxy. Seyfert galaxies are home to one of the most common subclasses of AGNs, along with quasars. The exact classification of AGNs is nuanced, but Seyfert galaxies tend to be relatively nearby where the host galaxy can be clearly detected alongside the central AGN, whereas quasars are always very distant AGNs and their Its incredible brightness exceeds that of its host galaxy.
Understanding Seyfert galaxies and their spectra
Both Seyfert galaxies and quasars have further subclasses. For Seyfert galaxies, the main subcategories are type 1 and type 2. They are distinguished from each other by their spectra (the pattern created when light is split into its constituent wavelengths). The spectral lines emitted by Type 2 Seyfert galaxies are particularly associated with certain so-called “forbidden” emissions.
To understand why synchrotron radiation from galaxies is thought to be forbidden, it helps to understand why the spectrum exists in the first place. Spectra look the way they do because certain atoms and molecules absorb and emit light very reliably at very specific wavelengths.
The reason is quantum physics. Electrons (tiny particles orbiting the nucleus of atoms and molecules) can only exist at very specific energies, so electrons can only lose or gain very specific amounts of energy. These very specific amounts of energy correspond to specific wavelengths of light that are absorbed or emitted.
Discharge prohibition phenomenon
Forbidden emission lines are therefore spectral emission lines that should not exist according to certain rules of quantum physics. However, quantum physics is complex, and some of the rules used to predict quantum physics use assumptions that are appropriate for laboratory conditions on Earth.
Under these rules, this release is “prohibited” and ignored because it is unlikely. But in space, in the midst of incredibly energetic galactic nuclei, those assumptions no longer apply, and “forbidden” light has a chance to shine towards us.
Source: scitechdaily.com
