we propose to test current unifying models of active galactic nuclei by searching for and studying broad mid-infrared hydrogen recombination lines in several seyfert 2/narrow line x-ray galaxies. our observations will: 1) provide a qualitative test for such unifying models by succeeding or failing to detect a classical broad line region (velocity width >3000 km/s) in each of these sources at wavelengths where the interstellar dust obscuring the nuclei likely becomes transparent; 2) give quantitative estimates of the column of obscuration for material moving at different velocities; 3) establish the physical properties of the obscuring dust particles by determining an extinction curve from line ratios. points 2) and 3) taken together will give valuable information on the location of the obscuring medium, be it a very thick, parsec scale torus, or the nuclear molecular cloud layer on 10^2 pc scale. the key lines required for this study lie at wavelengths where the earth.s atmosphere has no or poor transmission.
Instrument
PHT40 , SWS06
Temporal Coverage
1996-08-13T08:13:38Z/1998-01-29T16:24:22Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
