Hi Fady.
I would agree to little part of Mr Rajguru M Mohan that generally Gaussian filter is used as low pass filter to remove high frequency component and band limit the signals. In your Case i am not sure about if it does perform the same task but you can say that. And as far as the center frequency thing is concerned i cannot disagree with Duy Le Nguyen. Anyway thank you for bringing up a good query.
Thanks