© X-ray: NASA/CXC/Nanjing Univ./P. Zhou et al. Radio: NSF/NRAO/VLA
Composite image of X-ray data from Chandra (blue) and radio emission from the very large array (red) of Sagittarius A East. Elements detected suggest this is the first remnant of a rare type Iax supernovas found in our galaxy.
Supernova explosions seed the galaxy with
elements vital for life and serve as tracers
revealing the fate of the universe to us. Yet for all their importance, they include some sub-types we barely understand. Perhaps the most confusing are those known as Type Iax (pronounced one-ax), but the possible remnants of one of these events could provide some major clues to understanding them, and it could be the
first one ever found in the Milky Way.
Before we had any idea what caused them, supernovas - powerful, luminous stellar explosions - were categorized based on their dominant spectral lines. The most useful of these for research purposes turned out to be those known as Type Ia, which have the very convenient trait of always being roughly the same in their intrinsic brightness. By measuring how much light we see from a Type Ia supernova astronomers can get a good estimate of how far away the explosion, and therefore the galaxy in which it is housed, is from us.
This has served us well enough to reveal the fact the universe's expansion is accelerating, but between one-sixth and one-third of what at first looks like Ia supernovae aren't. Among these are a group sometimes called Type Iax supernovas, which have a spectrum marked by ionized silicon like ordinary Type Ias, but are considerably fainter.
While at the University of Amsterdam, study lead Ping Zhou observed a supernova remnant known as Sagittarius A East using the Chandra X-Ray telescope. Zhou thinks this is the first residue of an Iax supernova we have found in our galaxy.
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