Sgr A East is a supernova remnant at the very centre of the Milky Way, an elongated shell that wraps around the black hole Sgr A* from behind.
At a glance
| type | supernova remnant |
|---|---|
| distance from the Sun | 26,700 light-years (8.18 kpc) |
| its light left it | 26,700 years ago |
| size in the piece | about 27 light-years acrossmodel |
Read off the piece’s own catalogue, the same values it draws with. Model marks a property of the piece’s galaxy model rather than a measurement.
About Sgr A East
The radio source Sagittarius A breaks up into parts: the black hole Sgr A*, the spiral of gas around it called Sgr A West, and a larger shell, Sgr A East. The shell is a supernova remnant, and radio measurements show that it lies behind the black hole as we look at it from Earth.
X-ray telescopes see hot gas filling its centre, rich in heavy elements such as iron, the product of a stellar explosion. The remnant is pressing into the dense molecular gas of the Galactic centre and is thought to have pushed against the circumnuclear disc around the black hole. Few remnants are known in such an extreme environment, packed with stars, gas and strong magnetic fields.
What you see in the piece
Fly to the Galactic centre and switch to radio or X-ray: in visible light the thick dust in between makes the whole region dark from here.
Measured or modelled
How energetic the explosion was and how much it has shaped the gas near Sgr A* are still debated. The extent shown in the piece is modelled.
Questions
What is Sgr A East?
It is the remnant of a supernova that exploded near the centre of the Galaxy, seen in radio and X-rays as a shell lying just behind the black hole Sgr A*.
How far away is Sgr A East?
Sgr A East is about 26,700 light-years (8.18 kpc) from the Sun, at the Galactic centre.