Consistency of the Infrared Variability of SGR A* over 22yr

We report new near-infrared (NIR) measurements of the supermassive black hole at the Galactic Center, Sgr A*, using early speckle data at the Keck Observatory taken prior to 2002. The improved speckle holography technique has enabled the detection of Sgr A* in the majority of speckle epochs covering 7 years. The average observed K magnitude of Sgr A* (1995 - 2005) is 16.0, which corresponds to a dereddened flux density of 3.4 mJy. The brightness and its variability is consistent over 22 years based on extrapolation modeled from AO-based short-term variability studies (2006 - 2016). We also present that the 2001 periapse of the extended, dusty object G1 had no apparent effect on the NIR emission from accretion flow onto Sgr A*.