Physics
Scientific paper
Jan 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009eimw.confe..54r&link_type=abstract
"The Evolving ISM in the Milky Way and Nearby Galaxies, The Fourth Spitzer Science Center Conference, Proceedings of the confere
Physics
Galaxies: Ism, Galaxies: Spiral, Galaxies: Individual: Ngc 891, Methods: Numerical
Scientific paper
The sources of ionization and heating of the diffuse ionized gas in spiral galaxy disks and halos remain unclear. The usual optical diagnostic line ratios suffer from dependence on a confusing number of variables: not only the ionization state but also the temperature and abundance of the gas, as well as extinction. The Spitzer Space Telescope provides the opportunity to study the [Ne III]/[Ne II] mid-IR diagnostic, for which temperature, gas-phase abundance and extinction (although see below) effects are unimportant. Here we report the first detection of these lines in a spiral galaxy halo, and find that the ratio is enhanced in the halo relative to the disk. Using a 2-D Monte Carlo-based photo-ionization code which accounts for the effects of radiation field hardening, we find that this trend cannot be reproduced by any plausible photo-ionization model. We also report the first spectroscopic detections of PAH molecules in an external galaxy halo. Their emission suggests rough scale-heights of 300--500 pc.
Benjamin Robert A.
Rand Richard J.
Wood Kathleen
No associations
LandOfFree
Mid-IR Spectroscopy of the Diffuse Ionized Halo of NGC 891 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Mid-IR Spectroscopy of the Diffuse Ionized Halo of NGC 891, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mid-IR Spectroscopy of the Diffuse Ionized Halo of NGC 891 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1562857