On the identification of the C-60(+) interstellar features

The identity of the carriers of the diffuse interstellar bands (DIBs) is on e of the most fascinating puzzles of modern spectroscopy. Over the last few years the number of known DIBs has grown substantially. In this paper we d iscuss the two recently discovered near-infrared weak interstellar features which have already been proposed as fingerprints of the buckminsterfullere ne C-60(+). We present and discuss measurements of the two related DIBs wit hin a larger sample of reddened targets, observed with different spectromet ers, telescopes and site conditions. We provide additional arguments in fav our of the interstellar origin of the two bands. We find evidence around th e 9577-Angstrom DIB of far-wing structures, which may affect broad-band mea surements. We estimate corrections and errors for telluric and stellar blen ds, and show that the cores of the two DIBs are well correlated with a rati o near unity within 20 per cent. Finally, we discuss their relation to the laboratory spectra of C-60(+), and the search for two expected weaker C-60( +) transitions.