In 1922, Mary Lea Heger, a PhD student at the Lick Observatory, identified some faint absorption features of unknown origin in the spectra of stars. Soon after, astronomers realized that they were created in the material between stars, the so-called Interstellar Medium and as such, they named them "diffuse interstellar bands" (DIBs). Almost one century after their discovery, astronomers know more than 400 of these bands. However, they have not yet identified what causes them. The best candidates are some kind of large carbon-based molecules and as such, these bands could be the footprint of the largest reservoir of organic matter in galaxies. This is, however, a extremely faint footprint, and therefore difficult to spot. Maps for some of the bands exits only for some areas of the Milky Way and only in galaxies of the Local Group has been possible to spot this footprint at several locations within the galaxy.
Using data of the new instrument MUSE at the VLT, a team of astronomers led by Ana Monreal-Ibero, at GEPI, and Peter Weilbacher at Leibniz-Institut für Astrophysik Potsdam has just detected one of the mysterious features over a large extent of the member with highest extinction in an interacting system nicknamed "The Dentist’s Chair". The galaxy, at 160 Mpc, is at a distance more than 2 orders of magnitude larger than any other galaxy with detection of these features at several locations. With this discovery, the team demonstrate that mapping of this footprint in distant galaxies is possible. Thanks to the combination of high sensitivity instruments and large telescopes, astronomers will be able to answer one day the question: At what stage in the evolution of galaxies and in which favourable conditions have emerged in organic species still mysterious?
Link to the scientific publication: http://www.aanda.org/articles/aa/abs/2015/04/aa25854-15/aa25854-15.html