Matthews et al report first time-series measurements of SgrA* IR's broadband infared color

Hornstein, S. D. and Matthews, K. and Ghez, A. M. and Lu, J. R. and Morris, M. and Becklin, E. and Baganoff, F. K. and Rafelski, M. (2006)
Infrared/X-ray intensity variations and the color of Sgr A*. Journal of Physics: Conference Series, 54: 399-405, 2006. CaltechAuthors