Science with the Galactic O-Star Spectroscopic Survey (GOSSS) : The relationship between DIBs, ISM, and extinction

TL;DR

This study analyzes the relationship between Diffuse Interstellar Bands (DIBs), interstellar absorption lines, and extinction using a large sample of Galactic O-star spectra to better understand their origins and correlations.

Contribution

It provides new insights into DIBs and interstellar lines by utilizing the largest Galactic O-star spectroscopic sample to date, revealing correlation patterns with extinction.

Findings

High correlation between DIBs and E(B - V)

Moderate correlation between Ca II {934} and E(B - V)

Distinct spatial distribution of Ca II {934} related to line saturation

Abstract

In this poster we show our preliminary analysis of DIBs (Diffuse Interstellar Bands) and other interstellar absorption lines with the purpose of understanding their origin and their relationship with extinction. We use the biggest Galactic O-star blue-violet spectroscopic sample ever (GOSSS, see contribution by Ma\'iz Apell\'aniz at this meeting). This sample allows a new insight on this topic because of the adequacy of O-star spectra, the sample number (700 and increasing, 400 used here), and their distribution in the MW disk. We confirm the high correlation coefficients between different DIBs and E(B - V), though the detailed behavior of each case shows small differences. We also detect a moderately low correlation coefficient between Ca II {\lambda}3934 (Ca K) and E(B - V) with a peculiar spatial distribution that we ascribe to the relationship between line saturation and velocity profiles for Ca II {\lambda}3934.