Complex carbon chemistry and the diffuse interstellar bands in the magellanic clouds

Our research is directed at identifying the carriers of the diffuse interstellar bands (DIBs), observed in spectra of bright reddened stars shining through interstellar clouds. These absorption features, believed to arise from complex carbon molecules, are important to understand interstellar carbon chemistry. Pending their identification, DIBs will be important diagnostic tools to probe the chemistry of. the interstellar medium (ISM). In order to study a wide range of environmental effects (such as metal content, irradiation conditions) we have initiated a search for DIBs outside our own Galaxy, in our nearby neighbours the Large and Small Magellanic Cloud (LMC & SMC), which are at 50 and 60 kpc resp. These galaxies have a much lower metallicity (factor 2.5 and 10 smaller) than our galaxy and different star-formation fields. The extreme sensitivity of the Very Large Telescope in Chile has been exploited to detect small narrow DIBs in the SMC (for the first time) and LMC. From measurements of the strengths of DIBs in our spectra we conclude that although metallicity is an important factor, other properties like the UV irradiation field and star formation activity may play an important role as well.