the FUSE AGN Working Group

arXiv2004

Intrinsic Absorption in NGC 7469

We present results from a coordinated FUSE, HST/STIS and Chandra campaign to study intrinsic UV and X-ray absorption in the outflow of the Seyfert 1 galaxy NGC 7469. Previous non-simultaneous observations of this outflow found two distinct UV absorption components, one of which likely corresponds to the X-ray absorber. The FUSE data reveal that the O VI absorption in this component has strengthened over time, as the continuum flux decreased. We use measured H I, N V, C IV, and O VI column densities to model self-consistently the photoionization state of the absorbers. We confirm the physical picture of the outflow in which the low velocity component is a highly ionized, high density absorber located near the broad emission line region, while the high velocity component is of lower density and resides farther from the central engine.

astro-ph↗

arXiv2004

A Far-Ultraviolet Spectroscopic Survey of Low-Redshift AGN

Using the Far Ultraviolet Spectroscopic Explorer (FUSE) we have obtained 87 spectra of 57 low-redshift (z<0.15) active galactic nuclei (AGN). This sample comprises 53 Type 1 AGN and 4 Type 2. All the Type 1 objects show broad O VI 1034 emission; two of the Type 2s show narrow O VI emission. In addition to O VI, we also identify emission lines due to C III 977, N III 991, S IV 1062,1072, and He II 1085 in many of the Type-1 AGN. Of the Type 1 objects, 30 show intrinsic absorption by the O VI 1032,1038 doublet. Most of these intrinsic absorption systems show multiple components with intrinsic widths of 100 km/s spread over a blue-shifted velocity range of less than 1000 km/s. Galaxies in our sample with existing X-ray or longer wavelength UV observations also show C IV absorption and evidence of a soft X-ray warm absorber. In some cases, a UV absorption component has physical properties similar to the X-ray absorbing gas, but in others there is no clear physical correspondence between the UV and X-ray absorbing components. Models in which a thermally driven wind evaporates material from the obscuring torus naturally produce such inhomogeneous flows.

astro-ph↗