What does "Sgr A*" mean?
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Sgr A* is a supermassive black hole located at the center of our Milky Way galaxy. It is surrounded by a disk of gas and dust, and its gravitational pull is so strong that not even light can escape from it.
Observations and Activity
Scientists study Sgr A* using various telescopes that capture light across different wavelengths, from radio waves to X-rays. These observations have shown that Sgr A* can become very active, exhibiting flares that release massive amounts of energy.
Accretion Flow
The material falling into Sgr A* forms what is known as an accretion flow. Scientists have noticed features within this flow that suggest hotspots where energy and particles are being emitted. These can be tracked over time, giving researchers important clues about the behavior of the black hole and its surrounding environment.
Cosmic Rays and Galactic Activity
Sgr A* has likely gone through several active phases in the last few million years, which may have created large structures in the galaxy. Scientists have looked into whether activity from Sgr A* could significantly affect the cosmic rays—high-energy particles that travel through space—near Earth.
Recent studies suggest that while cosmic rays from the Galactic Center exist, their influence on the local cosmic ray environment is limited, particularly in the very high-energy range. This implies that past activities of Sgr A* may not have a noticeable impact on cosmic rays detected in our vicinity.