Spatially resolved studies of Diffuse Interstellar Bands in Galaxies beyond the Local Group
Diffuse Interstellar Bands (DIBs) are non-stellar weak absorption features of unknown origin found in the spectra of different astronomical objects when they are viewed through one or several clouds of Interstellar Medium. Galaxies other than ours offer the opportunity of study the behavior of DIBs under physical (e.g. radiation field) and chemical (e.g. metallicity and relative abundances) different to those typically found in the Milky Way. This can in turn, put further constrains on the nature of the agents creating these features. Because of their weakness, studies targeting extragalactic DIBs are relatively scarce. This is a research that will certainly blossom at the E-ELT era. However, we can already start paving the way.
In this talk, we will illustrate how MUSE can help us in this quest. I will use as examples some results on two highly reddened systems. In the first one, AM 1353-272, we established a gradient of DIB strength in a galaxy at more than 150 Mpc (Monreal-Ibero et al. 2015, A&A, 576, 3). In the second one, The Antennae Galaxy, we measured the strength of the l5780 and l5797 DIBs in more than 100 independent line of sights, thus mapping these DIBs in a system outside the Local Group for the first time (Monreal-Ibero et al. 2017, A&A, 615, 33). The distribution of DIB strength was compared with that of atomic hydrogen, molecular gas, and PAHs as traced by the emission in the mid-infrared. In both cases, DIB strength correlates well with extinction, similar to results for the Milky Way.
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