Is it possible to apply a gaussian filter to rasters in ArcMap without applying a calculation or otherwise program it yourself?
You can apply a Gaussian filter using the focal function with the
NbrWeight arguments to designate an ASCII kernel file representing the desired Gaussian Kernel distribution. You will have to look at the help to see what format the kernel file has to be in as, it is quite specific.
We have a Gaussian Smoothing tool in the Geomorphometry & Gradient Metrics Toolbox that will construct the kernel file using a specified kernel size (window) and sigma (standard deviation). The tool is under "Geomorphometry & Gradient Metrics > Statistics > Gaussian Smoothing"
ESRI provides two methods in the resample function which apply Gaussian filters to rasters. These are listed as Gauss Blur and Gauss Blur Plus.
See Resample Function in the ESRI help.