Long-term X-ray stability and UV variability of the ionized absorption
  in NGC 3783
  We present the results of recent Chandra High-Energy Transmission Grating
Spectrometer and Hubble Space Telescope Cosmic Origins Spectrograph
observations of the nearby Seyfert 1 galaxy NGC 3783 which shows a strong,
non-varying X-ray warm absorber and physically related and kinematically
varying UV absorption. We compare our new observations to high-resolution, high
signal-to-noise archival data from 2001, allowing a unique investigation into
the long-term variations of the absorption over a 12 yr period. We find no
statistically significant changes in the physical properties of the X-ray
absorber, but there is a significant drop of ~40% in the UV and X-ray flux, and
a significant flattening of the underlying X-ray power-law slope. Large
kinematic changes are seen in the UV absorbers, possibly due to radial
deceleration of the material. Similar behavior is not observed in the X-ray
data, likely due to its lower velocity resolution, which shows an outflow
velocity of v ~ -655 km/s in both epochs. The narrow iron K-alpha emission line
at 6.4 keV shows no variation between epochs, and its measured width places the
material producing the line at a radial distance of ~0.03 pc from the central
black hole.
