Interstellar H2 in M 33 detected with FUSE

Interstellar H 2 in M 33 detected with Fuse ⋆

Fuse spectra of the four brightest H ii regions in M 33 show absorption by interstellar gas in the Galaxy and in M 33. On three lines of sight molecular hydrogen in M 33 is detected. This is the first measurement of diffuse H2 in absorption in a Local Group galaxy other than the Magellanic Clouds. A quantitative analysis is difficult because of the low signal to noise ratio and the systematic e...

O-33: Serum Anti-M

Physical Conditions and Spatial Structure in the Molecular Interstellar Medium of M 33

Early studies of molecular gas in M33 used the CO J=1-0 transition to map out the total gas content in the inner kiloparsec of the galaxy and to study the properties of the giant molecular cloud population. In this review, I discuss recent detailed studies of individual molecular clouds in M33 in higher rotational transitions of CO, CO, and the fine structure line of atomic carbon. These data r...

Intermediate scale structure of the interstellar medium towards NGC 6231 in Sco OB 1 with FUSE ⋆

The FUSE far-ultraviolet interstellar spectra toward seven targets in NGC 6231 show that the molecules H 2 , HD, and CO as well as various atomic species are distributed in several clouds. The main absorption component found on the sight lines lies in the Lupus cloud region at a distance of about 150 pc, and there is a weaker second one, presumably in the Sco OB1 shell surrounding NGC 6231 (d ≃...

H2 Formation on Interstellar Grains in Different Physical Regimes

An analysis of the kinetics of H2 formation on interstellar dust grains is presented using rate equations. It is shown that semi-empirical expressions that appeared in the literature represent two different physical regimes. In particular, it is shown that the expression given by Hollenbach, Werner & Salpeter [ApJ, 163, 165 (1971)] applies when high flux, or high mobility, of H atoms on the sur...