On correlations between diffuse interstellar bands

TL;DR

This study investigates correlations among diffuse interstellar bands (DIBs) across multiple lines of sight to infer whether they share common carriers, revealing mostly weak correlations and only one strict correlation example.

Contribution

It introduces an observational test for DIB correlations across 10 bands in 62 Galactic lines of sight, highlighting the rarity of strict correlations among DIBs.

Findings

Most DIBs do not strictly correlate, indicating different carriers.

A strict correlation was found between DIBs at 6614 and 6196 Å.

Weak correlations suggest diverse molecular carriers for DIBs.

Abstract

One way to better apprehend the problem of diffuse interstellar bands (DIBs) is to search for correlations between the bands in a large sample of spectra towards various lines of sight: a strict correlation may imply that a common carrier is at the origin of the bands, whereas a non-correlation means that different species are involved. We propose this observational test for 10 DIBs collected in up to 62 Galactic lines of sight. Strong DIBs do not strictly correlate, and sometimes the correlation is very poor. Only one example of a strict correlation has been found in our sample between the DIBs at 6614 and 6196 A, that could significate a single carrier for those two bands. The general absence of strict correlations is discussed in the context of molecular carriers for the DIBs.