For those curious, this supernova is unfortunately too old to find the supernova remnant that was left behind. The most famous SNRs are Cas A [1] and M1/the Crab Nebula [2].<p>When the core of a massive star collapses, the resulting explosion launches the rest of the star surrounding the core outwards. Near to the star, this explosion proceeds as an unimpeded free expansion for a few hundred years, but the ejecta eventually impacts the gas between the stars, the interstellar medium. The ejecta then goes through two phases, an adiabatic phase (ie can't efficiently radiate away the heat) and radiative phase (ie can efficiently radiate away the heat). The adiabatic phase ends after around a couple ten thousand years, and the radiative phase ends after a few hundred thousand. As the remnant evolves, the gas becomes cooler and less dense, until eventually it's indistinguishable from the rest of the interstellar medium. So, if this supernova occurred around 2 million years ago, we shouldn't be able to observe the remnant. A shame!<p>[1] <a href="https://apod.nasa.gov/apod/ap050615.html" rel="nofollow">https://apod.nasa.gov/apod/ap050615.html</a>
[2] <a href="https://apod.nasa.gov/apod/ap150816.html" rel="nofollow">https://apod.nasa.gov/apod/ap150816.html</a>
FYI: Supernova link to ancient extinction [2002] <a href="http://physicsworld.com/cws/article/news/2002/feb/13/supernova-link-to-ancient-extinction" rel="nofollow">http://physicsworld.com/cws/article/news/2002/feb/13/superno...</a>
Here is a link to the full html article [1] and the pdf [2] The links are a bit hard to find from the abstract page. The html version has some messed up formatting but the pdf is fine. The DOI is: 10.1073/pnas.1601040113<p>[1] <a href="http://www.pnas.org/content/113/33/9232.full" rel="nofollow">http://www.pnas.org/content/113/33/9232.full</a> [2] <a href="http://www.pnas.org/content/113/33/9232.full.pdf" rel="nofollow">http://www.pnas.org/content/113/33/9232.full.pdf</a>