The Far Ultraviolet Spectroscopic Explorer Detection of Galactic O VI Emission in the Halo above the Perseus Arm
Abstract
Background observations obtained with the Far Ultraviolet Spectroscopic Explorer toward l=95.4d, b=36.1d show O VI λλ1032, 1038 in emission. This sight line probes a region of stronger than average soft X-ray emission in the direction of high-velocity cloud Complex C above a part of the disk in which Hα filaments rise into the halo. The O VI intensities, 1600+/-300 photons s-1 cm-2 sr-1 (1032 Å) and 800+/-300 photons s-1 cm-2 sr-1 (1038 Å), are the lowest detected in emission in the Milky Way to date. A second sight line nearby (l=99.3d, b=43.3d) also shows O VI λ1032 emission but with too low a signal-to-noise ratio to obtain reliable measurements. The measured intensities, velocities, and FWHMs of the O VI doublet and the C II* line at 1037 Å are consistent with a model in which the observed emission is produced in the Galactic halo by hot gas ejected by supernovae in the Perseus arm. An association of the observed gas with Complex C appears unlikely.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2003
- DOI:
- 10.1086/374731
- arXiv:
- arXiv:astro-ph/0302251
- Bibcode:
- 2003ApJ...586L..53O
- Keywords:
-
- Galaxy: Halo;
- Galaxy: Kinematics and Dynamics;
- Galaxy: Structure;
- ISM: General;
- ISM: Kinematics and Dynamics;
- ISM: Structure;
- Astrophysics
- E-Print:
- accepted for publication in ApJL, 11 pages including 3 figures