Incidence of Mg II absorption systems towards flat-spectrum radio
  quasars
  The conventional wisdom that the rate of incidence of Mg II absorption
systems, dN/dz (excluding `associated systems' having velocity beta*c relative
to the AGN of less than ~5000 km/s) is totally independent of the background
AGN, has been challenged by a recent finding that dN/dz for strong Mg II
absorption systems towards distant blazars is 2.2 \pm_{0.6}^{0.8} times the
value known for normal optically-selected quasars (QSOs). This has led to the
suggestion that a significant fraction of even the absorption systems with beta
as high as 0.1 may have been ejected by the relativistic jets in the blazars,
which are expected to be pointed close to our direction. Here we investigate
this scenario using a large sample of 115 flat-spectrum radio-loud quasars
(FSRQs) which too possess powerful jets, but are only weakly polarized. We
show, for the first time, that dN/dz towards FSRQs is, on the whole, quite
similar to that known for QSOs and the comparative excess of strong \mgii
absorption systems seen towards blazars is mainly confined to beta< 0.15. The
excess relative to FSRQs can probably result from a likely closer alignment of
blazar jets with our direction and hence any gas clouds accelerated by them are
more likely to be on the line of sight to the active quasar nucleus.
