Astronomers Have Calculated How Much Energy The Milky Way's Core Generates.
American astrophysicists first calculated how much light and heat the core of the milky Way produces and found on its periphery an energy source of unknown nature that actively ionizes hydrogen atoms. This was reported on Friday by the press service of the Embry-riddle Aeronautical University, with reference to an article in the journal Science Advances.
"Prior to our discovery, the nearest galaxy with such a region was the Andromeda Nebula. It is a neighbor of the milky Way, but it is still located millions of light-years away. The core of the Galaxy is only a few tens of thousands of light-years away from us, which allows us to study this area in detail and look for possible sources of this radiation," said Matthew Haffner, associate Professor at Embry - riddle Aeronautical University in Daytona (USA), whose words are quoted by the press service of the University.
At the center of presumably all the galaxies of the universe, there is one or even several supermassive black holes. Unlike other objects of this kind in some nearby galaxies, which are constantly attracting and absorbing matter, the black hole in the center of the Milky Way is in a kind of hibernation. Because of this, it does not produce powerful plasma emissions and remains invisible to virtually all telescopes except radio-wave and x-ray observatories.
This feature of the core of the milky Way, as well as the surrounding thick "coat" of dust and gas, does not allow scientists to see what is happening in the Central regions of the Galaxy, and understand how much energy it generates and what objects generate it. This is crucial for understanding what the milky Way would look like to observers outside of it.
Haffner and his colleagues obtained the first data of this kind by analyzing information collected by the Wisconsin H-Alpha mapper telescope over the past two decades. It was built in Chile in the mid-1990s to observe the glow of ionized hydrogen atoms discovered in intergalactic space above and below the disk of the Galaxy back in the late 1970s.
A unique chance for astronomy
Using its images, astronomers were able to measure how strongly ionized interstellar matter is in different regions of the milky Way's core, as well as determine the sources of its ionization. On the one hand, these measurements showed that in the immediate vicinity of Sgr A*, the main source of energy was young stars, which corresponds to current ideas about the appearance of the Galaxy.
On the other hand, scientists found that this was not the case on the outskirts of the milky Way's core. Atoms of hydrogen and other elements were ionized here by some unknown source of energy, the nature of which is not yet clear to astrophysicists. At the same time, as it turned out, the spectrum of radiation produced by it was very similar to the glow that generates a special class of objects, which scientists call LINER-galaxies.
Their main feature is that most of the radiation in their Central regions are generated by relatively weakly ionized or even neutral atoms of hydrogen, oxygen, nitrogen, sulfur, and other elements. LINER includes about a third of nearby galaxies, but scientists still do not know what exactly produces this glow and where it occurs. For example, some researchers believe that its source is supermassive black holes, while others suggest that it occurs in regions of star formation. The mechanism of ionization of atoms is not clear, nor is it clear why the number of" liners " includes galaxies of all types and sizes.
The discovery, Haffner notes, gives astronomers a unique chance to study the sources of this mysterious radiation and understand what role they play in shaping the appearance and evolution of LINER galaxies.