we propose to use sws on board the iso satellite to search for hidden broad line regions (blr) in a sample of seyfert 2 galaxies from intermediate resolution observations of the emission lines brackett alpha (4.05 micron) and pfund alpha (7.46 micron). the observations will allow us the detection of any broad component obscured up to 180 magnitudes in the visible (goodrich et al. 1994). this represents a significant improvement, w.r.t. previous works, in the penetration of the molecular/dust torus around the blr and continuum source predicted by the unification models and therefore the proposed observations will constitute one of the most powerful tests of such models. it is expected to extend considerably the sample of hidden seyfert 1 known to date. additionally, we will determine the reddening of the nlr and of the blr (if detected) and, from the comparison of the reddening of the detected blr with that inferred from the column densities of intervening material obtained from soft x-ray observations, we will be able to deduce several important properties of the gas such as the mean dust-to-gas ratio along the line of sight. also very important information will be extracted from the analysis of the widths of the profiles. we will search for the presence of systematic increases in the width at longer wavelengths in both the nlr and the blr by internal comparison of our data and with the optical lines. this will provide direct evidence of velocity stratification in both line-emitting regions as a function of optical depth, which can be compared with current models of cloud velocity distribution present in the literature.
Instrument
SWS02
Temporal Coverage
1996-08-05T10:06:03Z/1996-11-04T00:12:40Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds 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.
European Space Agency, PEREZ-FOURNON et al., 1999, 'SEARCH FOR HIDDEN BLR IN SEYFERT 2 GALAXIES TEST OF UNIFICATION THEORIES FOR SEYFERTS', 1.0, European Space Agency, https://doi.org/10.5270/esa-sx2djfl
