  We present a study of the X-ray flaring activity of Sgr A* during all the 150
XMM-Newton and Chandra observations pointed at the Milky Way center over the
last 15 years. This includes the latest XMM-Newton and Chandra campaigns
devoted to monitoring the closest approach of the very red Br-Gamma emitting
object called G2. The entire dataset analysed extends from September 1999
through November 2014. We employed a Bayesian block analysis to investigate any
possible variations in the characteristics (frequency, energetics, peak
intensity, duration) of the flaring events that Sgr A* has exhibited since
their discovery in 2001. We observe that the total bright-or-very bright flare
luminosity of Sgr A* increased between 2013-2014 by a factor of 2-3 (~3.5 sigma
significance). We also observe an increase (~99.9% significance) from
0.27+-0.04 to 2.5+-1.0 day^-1 of the bright-or-very bright flaring rate of Sgr
A*, starting in late summer 2014, which happens to be about six months after
G2's peri-center passage. This might indicate that clustering is a general
property of bright flares and that it is associated with a stationary noise
process producing flares not uniformly distributed in time (similar to what is
observed in other quiescent black holes). If so, the variation in flaring
properties would be revealed only now because of the increased monitoring
frequency. Alternatively, this may be the first sign of an excess accretion
activity induced by the close passage of G2. More observations are necessary to
distinguish between these two hypotheses.
