The X-ray mission Chandra has observed a dramatic X-ray flare – a brightening by a factor of 50 for only three hours – from Sgr A* , the Galactic Center supermassive black hole .
Sgr A* has never shown variability of this amplitude in the radio and we therefore argue that a jump of this order in the accretion rate does not seem the likely cause .
Based on our model for jet-dominated emission in the quiescent state of Sgr A* , we suggest that the flare is a consequence of extra electron heating near the black hole .
This can either lead to direct heating of thermal electrons to T _ { e } \sim 6 \cdot 10 ^ { 11 } K and significantly increased synchrotron-self Compton emission , or result from non-thermal particle acceleration with increased synchrotron radiation and electron Lorentz factors up to \gamma _ { e } \ga 10 ^ { 5 } .
While the former scenario is currently favored by the data , simultaneous VLBI , submm , mid-infrared and X-ray observations should ultimately be able to distinguish between the two cases .