First results from a study of DIBs with thousands of high-quality massive-star spectra

TL;DR

This study compiles the largest high-quality dataset of diffuse interstellar bands (DIBs) from multiple surveys of OB stars, revealing new DIBs and potential carriers, advancing understanding of interstellar medium properties.

Contribution

It presents the first results from a large-scale survey of DIBs, including detection of previously elusive DIBs and analysis of their properties using extensive high-resolution spectra.

Findings

Detection of two previously elusive DIBs at 4170 Å and 4591 Å.

Identification of potential carriers for the 4591 Å DIB as coronene and ovalene cations.

Compilation of a large, high-quality dataset of DIB measurements across 4100-5500 Å.

Abstract

We are using five different surveys to compile the largest sample of diffuse interstellar band (DIB) measurements ever collected. GOSSS is obtaining intermediate-resolution blue-violet spectroscopy of ~2500 OB stars, of which 60% have already been observed and processed. The other four surveys have already collected multi-epoch high-resolution optical spectroscopy of 700 OB stars with different telescopes, including the 9 m Hobby-Eberly Telescope in McDonald Observatory. Some of our stars are highly-extinguished targets for which no good-quality optical spectra have ever been published. For all of the targets in our sample we have obtained accurate spectral types, measured non-DIB ISM lines, and compiled information from the literature to calculate the extinction. Here we present the first results of the project, the properties of twenty DIBs in the 4100-5500 {\AA} range. We clearly detect a couple of previously elusive DIBs at 4170 {\AA} and 4591 {\AA}; the latter could have coronene and ovalene cations as carriers.