Microlensing variability in FBQ 0951+2635: short-timescale events or a
  long-timescale fluctuation?
  We present and analyse new R-band frames of the gravitationally lensed double
quasar FBQ 0951+2635. These images were obtained with the 1.5m AZT-22 Telescope
at Maidanak (Uzbekistan) in the 2001-2006 period. Previous results in the R
band (1999-2001 period) and the new data allow us to discuss the dominant kind
of microlensing variability in FBQ 0951+2635. The time evolution of the flux
ratio A/B does not favour the continuous production of short-timescale (months)
flares in the faintest quasar component B (crossing the central region of the
lensing galaxy). Instead of a rapid variability scenario, the observations are
consistent with the existence of a long-timescale fluctuation. The flux ratio
shows a bump in the 2003-2004 period and a quasi-flat trend in more recent
epochs. Apart from the global behaviour of A/B, we study the intra-year
variability over the first semester of 2004, which is reasonably well sampled.
Short-timescale microlensing is not detected in that period. Additional data in
the i band (from new i-band images taken in 2007 with the 2m Liverpool Robotic
Telescope at La Palma, Canary Islands) also indicate the absence of
short-timescale events in 2007.
