EDP Sciences
Free Access
Volume 414, Number 3, February II 2004
Page(s) 949 - 954
Section Interstellar and circumstellar matter
DOI https://doi.org/10.1051/0004-6361:20031663

A&A 414, 949-954 (2004)
DOI: 10.1051/0004-6361:20031663

On the relation between diffuse bands and column densities of H $\mathsf{_{2}}$, CH and CO molecules

T. Weselak1, G. A. Galazutdinov2, 3, F. A. Musaev2, 3 and J. Krelowski4

1  Kazimierz Wielki Academy, Faculty of Physics, Weyssenhoffa Sqr. 11, 85-072 Bydgoszcz, Poland
    e-mail: towes@ab-byd.edu.pl
2  Special Astrophysical Observatory, Nizhnij Arkhyz 357147, Russia
    e-mail: gala@sao.ru
3  Isaac Newton Institute of Chile, SAO Branch
    e-mail: faig@sao.ru
4  Center for Astronomy, Nicolaus Copernicus University, Gagarina 11, 87-100 Torun, Poland
    e-mail: jacek@astri.uni.torun.pl

(Received 7 February 2003 / Accepted 11 September 2003 )

Mutual relations between column densities of H 2, CH and CO molecules as well as between the latter and strengths of the major 5780 and 5797 diffuse bands are presented and discussed. The CH radical seems to be a good H 2 tracer, possibly better than CO. It is also demonstrated that the molecular fraction of the H 2 molecule is correlated with an intensity ratio of 5797 and 5780 DIBs, suggesting the possible formation of narrow DIB carriers in denser clouds, dominated by molecular hydrogen and reasonably shielded from ionizing UV radiation by small dust grains.

Key words: ISM: molecules

Offprint request: T. Weselak, towes@ab-byd.edu.pl

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