Source-intrinsic near-infrared properties of Sgr A*: Total intensity
  measurements
  We present a comprehensive data description for Ks-band measurements of Sgr
A*. We characterize the statistical properties of the variability of Sgr A* in
the near-infrared, which we find to be consistent with a single-state process
forming a power-law distribution of the flux density. We discover a linear
rms-flux relation for the flux-density range up to 12 mJy on a timescale of 24
minutes. This and the power-law flux density distribution implies a
phenomenological, formally non-linear statistical variability model with which
we can simulate the observed variability and extrapolate its behavior to higher
flux levels and longer timescales. We present reasons why data with our cadence
cannot be used to decide on the question whether the power spectral density of
the underlying random process shows more structure at timescales between 25 min
and 100 min compared to what is expected from a red noise random process.
