17 minutes

The black hole at the center of the galaxy emits flares, and with
careful analysis, the people at the VLT say:
>>
The most striking result is an apparent 17-minute periodicity in the
light curves of two of the detected flares
<<

Something rotating with 1/17 minutes has a maximum radius if we assume
that its border (the circumference) can't travel faster than light.

At (vacuum) light speed, this is 18 360 000 000 Km, the distance light
travels in 17 minutes. The maximum circumference of the center can't
go beyond that, and the radius is that divided by 2*pi = 2 922 084 755
Km or 19.46 AU.

Is this reasoning correct?

Thanks

jacob

[Mod. note: reformatted -- mjh]