Hubble Space TelescopeSTIS Ultraviolet Spectral Evidence of Outflow in Extreme Narrow‐Line Seyfert 1 Galaxies. II. Modeling and Interpretation

Abstract

We present modeling to explore the conditions of the broad-line emitting gas in two extreme Narrow-line Seyfert 1 galaxies, using the observational results described in the first paper of this series. Photoionization modeling using Cloudy was conducted for the broad, blueshifted wind lines and the narrow, symmetric, rest-wavelength-centered disk lines separately. A broad range of physical conditions were explored for the wind component, and a figure of merit was used to quantitatively evaluate the simulation results. Of the three minima in the figure-of-merit parameter space, we favor the solution characterized by an X-ray weak continuum, elevated abundances, a small column density (log(N H ) ≈ 21.4), relatively high ionization parameter (log(U ) ≈ −1.2-−0.2), a wide range of densities (log(n) ≈ 7-11), and a covering fraction of ∼ 0.15. The presence of low-ionization emission lines implies the disk component is optically thick to the continuum, and the Si III]/C III] ratio implies a density of 10 10 -10 10.25 cm −3 . A low ionization parameter (log(U ) = −3) is inferred for the intermediate-ionization lines, unless the continuum is "filtered" through the wind before illuminating the intermediateline emitting gas, in which case log(U ) = −2.1. The location of the emission regions was inferred from the photoionization modeling and a simple "toy" dynamical model. A large black hole mass (1.3 × 10 8 M ⊙ ) radiating at 11% of the Eddington luminosity is consistent with the kinematics of both the disk and wind lines, and an emission radius of ∼ 10 4 R S is inferred for both. We compare these results with previous work and discuss implications. 3 We do not know with certainty the geometrical and physical origin of the emission lines in the objects we are -3 -The strongly blueshifted C IV profile suggested that it is dominated by emission in the wind. Following Baldwin et al. (1996), we used the C IV profile to develop a template for the wind. We then used this template, plus a narrow and symmetric component representing the disk emission, to model the other bright emission lines. We inferred that the high-ionization lines N V and He II are also dominated by wind emission, and a part of Lyα is emitted in the wind. A part of Lyα and the intermediate-and low-ionization lines Al III, Si III], C III], and Mg II are dominated by disk emission. The 1400Å feature, comprised of O IV] and Si IV was difficult to model; however, it appears to include both disk and wind emission. discussing here. However, for simplicity, we refer to the highly blueshifted high-ionization lines as originating in the "wind", and the narrow, symmetric low-ionization lines as originating in the "disk".

The mass and spin of the extreme Narrow Line Seyfert 1 Galaxy 1H 0707−495 and its implications for the trigger for relativistic jets

“…Physically, this could indicate that the clouds are optically thick to electron scattering, with columns of > 10 24 cm −2 (consistent with the low ionisation broad lines forming in the disc: Collin-Souffrin et al 1980), or that the radiative acceleration only affects the front face of the cloud (Baskin, Laor & Stern 2014b). However, part of the Hβ line is clearly blueshifted (Figure 1), indicating that these objects could be so extreme that even part of the low ionisation lines (as well as the high ionisation lines such as CIV) come predominantly from a wind (see also Leighly & Moore 2004;Leighly 2004).…”

“…Both are super-Eddington, but 1H0707 is more super-Eddington that PG1244, so has a stronger wind which explains its lack of narrow optical line emission by shielding the NLR, suppressing the narrow [OIII] lines compared to PG1244 (Leighly 2004). The combination of more highly superEddington flow leading to stronger mass loss, together with higher inclination angle means that the wind is more likely to be in the line of sight for 1H0707.…”

The Intermediate-Line Region in Active Galactic Nuclei

“…Additionally, a density of 10 10.25 cm −3 was found from the study of UV intrinsic absorbers of two NLSy1 galaxies (Leighly 2004). Finally, from photoionization calculations, Różańska et al (2014) found the density of an intrinsic absorbing cloud in the bright quasar HS 1603 + 3820 to be of the order of n H ∼ 10 10 − 10 12 cm −3 .…”

Detection of Rest-Frame Optical Lines From X-Shooter Spectroscopy of Weak Emission-Line Quasars

“…High-ionization lines (like C IV) are thought of as "wind" lines, because they can show a component with non-virialized motion, often interpreted in the context of a radiatively line driven wind. Some lines can have both a disk and wind component (see, e.g., Leighly 2004, and references therein). In order to drive a wind radiatively, the balance between the number of X-ray and UV photons is critical.…”