Long-term X-Ray Stability and Ultraviolet Variability of the Ionized Absorption in NGC 3783
Abstract
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 show a strong, nonvarying 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 out ~ -655 km s-1 in both epochs. The narrow iron Kα 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2014
- DOI:
- 10.1088/0004-637X/797/2/105
- arXiv:
- arXiv:1410.4569
- Bibcode:
- 2014ApJ...797..105S
- Keywords:
-
- galaxies: active;
- galaxies: individual: NGC 3783;
- galaxies: Seyfert;
- X-rays: galaxies;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 20 pages, 10 figures, 5 tables. Accepted for publication in ApJ