2009/12/30 by M. Kazmierczak, Marzena Kaźmierczak, M. Schmidt +4 · 2 citations
Physics and Astronomy · #Absorption spectroscopy #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Emission spectrum #Excitation #Excitation temperature #Galaxy #Interstellar medium #Mean kinetic temperature #Molecular cloud #Optics #Physics #Rotational temperature #Spectral line #Spectral resolution #Spectrograph #Stars #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1111/j.1365-2966.2009.16065.x
published as Monthly Notices of the Royal Astronomical Society, 2010, Volume 402, Issue 4, pp. 2548-2558 · 11 pages, 3 figures, MNRAS 2010
openalex publication_date 2009/12/30 · arxiv created 2010/09/27 · arxiv updated 2010/09/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Using high-resolution (∼85 000) and high signal-to-noise ratio (∼200) optical spectra acquired with the European Southern Observatory Ultraviolet and Visual Echelle Spectrograph, we have determined the interstellar column densities of C2 for six Galactic lines of sight with E(B–V) ranging from 0.33 to 1.03. For our purposes, we identified and measured absorption lines belonging to the (1, 0), (2, 0) and (3, 0) Phillips bands A1Πu–X1Σ+g. We report on the identification of a few lines of the C2(4, 0) Phillips system towards HD 147889. The curve-of-growth method is applied to the equivalent widths to determine the column densities of the individual rotational levels of C2. The excitation temperature is extracted from the rotational diagrams. The physical parameters of the intervening molecular clouds (e.g. gas kinetic temperatures and densities of collision partners) were estimated by comparison with the theoretical model of excitation of C2.