Strengthening the Link Between Fullerenes and a Subset of Diffuse Interstellar Bands

Abstract

A debate persists regarding the correlation between the DIBs 9577 and 9632 à , and whether they share a common molecular carrier (i.e., C${}_{60}^{+}$). A robust high correlation determination emerges after bridging the baseline across an order of magnitude ($\simeq 50-700$ mà , $r=0.93\pm 0.02$), and nearly doubling the important higher equivalent width domain by adding new Mg II-corrected sightlines. Moreover, additional evidence is presented of possible DIB linkages to fullerenes, whereby attention is drawn to DIBs at 7470.38, 7558.44, and 7581.47 à , which match the Campbell experimental results for C${}_{70}^{+}$ within 1 à , and the same is true of 6926.48 and 7030.26 à for C${}_{70}^{2+}$. Yet their current correlation uncertainties are unsatisfactory and exacerbated by expectedly low EWs (e.g., $\overline{EW}=4$ mà for 6926.48 à ), and thus further observations are required to assess whether they represent a bona fide connection or numerical coincidence.

To appear in publication