Discovery of a fast, broad, transient outflow in NGC 985
  We observed the Seyfert 1 galaxy NGC 985 on multiple occasions to search for
variability in its UV and X-ray absorption features in order to establish their
location and physical properties. We use XMM-Newton to obtain X-ray spectra
using the EPIC-pn camera, and the Cosmic Origins Spectrograph (COS) on the
Hubble Space Telescope (HST) to obtain UV spectra. Our observations are
simultaneous and span timescales of days to years. We find that the soft X-ray
obscuration that absorbed the low energy continuum of NGC 985 in August 2013
diminished greatly by January 2015. The total X-ray column density decreased
from 2.1 x 10^22 cm^-2 to ~6 x 10^21 cm^-2. We also detect broad, fast UV
absorption lines in COS spectra obtained during the 2013 obscuration event.
Lines of C III*, Ly alpha, Si IV and C IV with outflow velocities of -5970 km/s
and a full-width at half-maximum of 1420 km/s are prominent in the 2013
spectrum, but have disappeared in all but Ly alpha in the 2015 spectra. The
ionization state and the column density of the UV absorbing gas is compatible
with arising in the same gas as that causing the X-ray obscuration. The high
velocity of the UV-absorbing gas suggests that the X-ray obscurer and the
associated UV outflow are manifestations of an accretion disk wind.
