Radiation Pressure Confinement in Active Galaxies |
| TYPE | Astrophysics Seminar |
| Speaker: | Jonathan Stern |
| Affiliation: | Technion |
| Organizer: | Hagai Perets |
| Date: | 17.07.2013 |
| Time: | 14:30 - 15:30 |
| Location: | Lidow 620 |
| Abstract: | The pressure from the radiation of active galactic nuclei (AGN) can exceed the typical gas pressure in the interstellar medium by many orders of magnitude. We show that in luminous AGN, this radiation pressure likely confines the optically thick photoionized gas in the host galaxy. Radiation pressure confinement produces a unique hydrostatic solution, which is independent of the ambient pressure. The gas density within the photoionized gas scales as the distance from the nucleus to the power of -2. Thus, the AGN radiation pressure sets the density of the illuminated gas in the host galaxy. We show that this density vs. distance relation is observed over a dynamical range of ~10^4 in distance and ~10^8 in gas density. The unique hydrostatic solution implies a highly ionized X-ray emitting surface layer, and a lower ionization inner layer which emits optical lines. This slab structure can explain the observed overlap of the extended X-ray and optical line emission. We also compare the predicted ratios of the narrow lines strength with available observations. |