Position displacement of diffuse interstellar bands

TL;DR

This study confirms and extends previous observations of blue shifts in diffuse interstellar bands, revealing small-scale displacements and profile broadening, with some shifts exceeding 10 km/s, using high-quality spectra.

Contribution

It provides new evidence of small-scale displacements and broadening of diffuse interstellar bands with high-resolution spectra, confirming earlier findings with different instruments.

Findings

Confirmed blue shifts in diffuse bands using new instrument

Revealed small-scale displacements up to 10 km/s

Observed significant broadening of band profiles

Abstract

We re-consider the already published phenomenon: the blue shift of diffuse interstellar bands, observed in spectra of HD34078 (AE Aur) and members of the Sco OB1 association, in particular HD152233. We have analyzed 29 diffuse bands. Part of them, already proven as blue-shifted in our earlier study, are now confirmed using another instrument: this time the 6.5m Clay telescope equipped with the MIKE spectrograph. The high signal-to-noise ratio (over 600) of our spectra allowed us to reveal even small small scale {\bf displacements} of positions (both: blue and red-shifts) of diffuse bands along the considered lines of sight. In some cases the magnitude of deviation exceeds 10 km\,s$^{-1}$. Also, we prove that profiles of many diffuse bands in spectra of HD34078 suffer significant broadening. The origin of the observed phenomena is discussed.