Testing the Expanding Plasmon Model in the Galactic Center’s Black Hole

We investigate the temporal behavior of flares in the NIR and millimeter regime of Sagittarius A*, the supermassive black hole in the Galactic center, observed on 2005 July 31 at the Keck II telescope, the Very Large Telescope, and the Submillimeter Array. The time lags between a VLT NIR flare and SMA millimeter flare as well as between three quasi-simultaneous Keck NIR flares are quantified through application of the z-transform discrete cross correlation function. Through this analysis, we contribute a new value of approximately 160 minutes to the collection of NIR-mm time lag estimates and eliminate the previous outlying estimate of 20 minutes. Due to insignificant time lag estimates between inter-NIR flares, the validity of the expanding synchrotron plasmon model cannot be satisfactorily tested with current observations. We show that significant inter-NIR time lags can in principle be achieved by decreasing light curve sampling intervals.