'Tuple defining the default ``bounding_box`` limits,
``(x_low, x_high)``.
Parameters
factor : float
The multiple of FWHM used to define the limits.
Default is chosen to include most (99%) of the
area under the curve, while still showing the
central feature of interest.'

def bounding_box(self, factor=25):

    x0 = self.x_0
    dx = (factor * self.fwhm)
    return ((x0 - dx), (x0 + dx))
