[AG Abs.18 Pxx]

ORFEUS II Echelle Spectra: 
Slicing the Galactic Interstellar Medium at l=270°

Using high resolution Far-UV absorption line spectra from the ORFEUS II mission
in Nov./Dec. 1996 towards 15 stars, we analyse the Galactic disk interstellar
medium (ISM) in a strip in the sky extending from the northern to the southern
Galactic pole at roughly l=270°. Copernicus targets located in this direction
contribute additional information.

The target stars are rather nearby objects, however most of them are well beyond
the boundaries of the Local Bubble. Thus, mainly cold Galactic disk gas is
probed. With sight lines covering the whole sky between the Galactic poles, we
are then able to analyse the distribution of the interstellar gas in the
direction perpendicular to the plane of the Milky Way.

We derive column densities of molecular hydrogen for rotational excitation
states up to J=7 and of the main ionisation states of various metals (Si II, 
Fe II, S II, O I, N I, N II, P II, Ar I). Excitation temperatures range from 42
to 160 K. In addition, Voigt profile fits to the Lyman series absorption lines
provide column densities for H I.

A preliminary analysis of the spectra indicates a homogeneous distribution of 
the metals with typical disk-like column densities. In contrast, the abundance
of H_2 varies strongly over the various sight lines. Molecular gas in
significant amounts (log N > 17) is detected on about half of the lines of
sight.