Variable Reddening and Broad Absorption Lines in the Narrow-line Seyfert
  1 Galaxy WPVS 007: an Origin in the Torus
  We report the discovery of an occultation event in the low-luminosity
narrow-line Seyfert 1 galaxy WPVS 007 in 2015 February and March. In concert
with longer timescale variability, these observations place strong constraints
on the nature and location of the absorbing material. Swift monitoring has
revealed a secular decrease since ~2010 accompanied by flattening of the
optical and UV photometry that suggests variable reddening. Analysis of four
Hubble Space Telescope COS observations since 2010, including a Director's
Discretionary time observation during the occultation, shows that the
broad-absorption-line velocity offset and the CIV emission-line width both
decrease as the reddening increases. The occultation dynamical timescale, the
BAL variability dynamical timescale, and the density of the BAL gas show that
both the reddening material and the broad-absorption-line gas are consistent
with an origin in the torus. These observations can be explained by a scenario
in which the torus is clumpy with variable scale height, and the BAL gas is
blown from the torus material like spray from the crest of a wave. As the
obscuring material passes into our line of sight, we alternately see
high-velocity broad absorption lines and a clear view to the central engine, or
low-velocity broad absorption lines and strong reddening. WPVS 007 has a small
black hole mass, and correspondingly short timescales, and so we may be
observing behavior that is common in BALQSOs, but is not typically observable.
