A search for fine structure inside high resolution profiles of weak diffuse interstellar bands

¹ Center for Astronomy, Nicholas Copernicus University, Gagarina 11, 87-100 Toruń, Poland e-mail: [kasiek;jacek]@astri.uni.torun.pl
² Korean Astronomy Observatory, Optical Astronomy Division, 61-1, Whaam-Dong, Yuseong-Gu, Daejon, 305-348, Korea e-mail: gala@boao.re.kr
³ Special Astrophysical Observatory, Nizhnij Arkhyz 369167, Russia e-mail: faig@sao.ru
⁴ International Centre for Astronomical, Medical and Ecological Research (IC AMER), Terskol, 361605, Russia e-mail: arctur@terskol.com
⁵ N.Copernicus Astronomical Center, Rabiańska 8, 87-100 Toruń, Poland e-mail: schmidt@ncac.torun.pl

Received: 7 January 2005
Accepted: 4 October 2005

Abstract

This paper presents a survey of the high-resolution profiles of selected, moderately weak diffuse interstellar bands (DIBs) between 4725 and 6730 Å. In very high signal-to-noise spectra, obtained as a result of averaging several individual exposures of reddened, early-type stars that show Doppler splitting of <2 km s^-1 in interstellar gas lines, the profiles seem to have a substructure. This supports the molecular origin hypothesis for DIBs. We studied the profiles of the diffuse interstellar bands at wavelengths of 4726.33, 4963.85, 5418.89, 5541.74, 5544.95, 5546.46, 5762.73, 5766.05, 5769.09, 6439.41, 6445.53, 6449.16, 6729.28 Å.