A 'matryoshka' in the interstellar medium

As if it were one of the known Russian dolls, a group of astronomers, led by researchers at the Instituto de Astrofísica de Canarias, (IAC) has found the first known case of three supernova remnants one inside the other. Using the programme BUBBLY, a method developed within the group for detecting huge expanding bubbles of gas in interstellar space, they were observing the galaxy M33 in our Local Group of galaxies and found example of a triple-bubble. The results, which were published yesterday...