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

Understand

In this paper we examine properties of the variable source Sgr A* in the near-infrared (NIR) using a very extensive Ks-band data set from NACO/VLT observations taken 2004 to 2009.

• We investigate the variability of Sgr A* with two different photometric methods and analyze its flux distribution.
• We find Sgr A* is continuously emitting and continuously variable in the near-infrared, with some variability occurring on timescales as long as weeks.
• The flux distribution can be described by a lognormal distribution at low intrinsic fluxes (<~5 mJy, dereddened with A_{Ks}=2.5).