Not only once: the amazing gamma-ray activity of the blazar PKS 1510-089
  PKS 1510-089 is a powerful Flat Spectrum Radio Quasar at z=0.361 with
radiative output dominated by the gamma-ray emission. In the last two years PKS
1510-089 showed high variability over all the electromagnetic spectrum and in
particular very high gamma-ray activity was detected by the Gamma-Ray Imaging
Detector on board the AGILE satellite with flaring episodes in August 2007 and
March 2008. An extraordinary activity was detected in March 2009 with several
flaring episodes and a flux that reached 500 x 10^{-8} photons cm^{-2} s^{-1}.
Multiwavelength observations of PKS 1510-089 seem to indicate the presence of
Seyfert-like features such as little blue bump and big blue bump. Moreover,
X-ray observations suggested the presence of a soft X-ray excess that could be
a feature of the bulk Comptonization mechanism. We present the results of the
analysis of the multiwavelength data collected by GASP-WEBT, REM, Swift and
AGILE during these gamma-ray flares and the theoretical implications for the
emission mechanisms.
