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In this paper we examine properties of the variable source Sgr A* in thenear-infrared (NIR) using a very extensive Ks-band data set from NACO/VLTobservations taken 2004 to 2009. We investigate the variability of Sgr A* withtwo different photometric methods and analyze its flux distribution. We findSgr A* is continuously emitting and continuously variable in the near-infrared,with some variability occurring on timescales as long as weeks. The fluxdistribution can be described by a lognormal distribution at low intrinsicfluxes (<~5 mJy, dereddened with A_{Ks}=2.5). The lognormal distribution has amedian flux of approximately 1.1 mJy, but above 5 mJy the flux distribution issignificantly flatter (high flux events are more common) than expected for theextrapolation of the lognormal distribution to high fluxes. We make a generalidentification of the low level emission above 5 mJy as flaring emission and ofthe low level emission as the quiescent state. We also report here thebrightest Ks-band flare ever observed (from August 5th, 2008) which reached anintrinsic Ks-band flux of 27.5 mJy (m_{Ks}=13.5). This flare was a factor 27increase over the median flux of Sgr A*, close to double the brightness of thestar S2, and 40% brighter than the next brightest flare ever observed fromSgr~A*.

The two states of Sgr A* in the near-infrared: bright episodic flares on top of low-level continuous variability