The Critical 9365 Ã Diffuse Interstellar Band and C${}_{60}^{+}$ Association

Abstract

The detection of interstellar C${}_{60}^{+}$ has been debated for 30 years. The contested attribution of a weaker DIB at 9365 Ã was re-evaluated here on the basis of a Pearson correlation relative to 9577 Ã , which was previously tied to C${}_{60}^{+}$ by diverse collaborations. An assessment of 11 sightlines revealed a high correlation amongst 9365$-$9577 Ã equivalent widths ($r=0.93\pm 0.05$), after contamination from an adjacent line was mitigated using both numerical integration and Gaussian fits. In tandem with a recent separate study's high-$r$ evaluation linking 9577$-$9632 Ã across a sizable baseline: three interrelated DIBs matching C${}_{60}^{+}$ laboratory findings were independently reaffirmed (9365, 9577, 9632 Ã ). Yet further investigations are required to strengthen the case via two other weak DIBs disputedly linked to C${}_{60}^{+}$, particularly owing to potential overlapping lines arising from an expansive chemical space (PAHs).

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