[alma-config]My point of view

[Bryan Butler]

On 2002.01.30 12:42 Mark Holdaway wrote:

> >
> > and the signal coming from the direction of the max PSF
> > be attenuated by the PB at PB(de)
> 
> But IS there any signal coming from that direction?

i think leonia's argument is that there MIGHT be - in this sense it
is a worst case analysis.

> 
> > So the modified PSF (PSFmod) when we clean the component from the direcrion
> de
> > can be described by the following equation:
> >
> > PSFmod(e) = PSF(e) * PB(e+de) / PB(de)   (1)
> 
> I don't understand why you are dividing by the PB?
> In the mosaic process, you never divide by the PB.

i think this is like an 'effective SNR' argument.  if you take the 'signal' as
the flux density of the source you observe, then it is attenuated by being
down on the PB.  the 'noise' is the confusing source signal, which is the
actual source strength X sidelobe level X PB at the confusing source location.
so leonia's eqn. 1 is like the effective SNR in the dirty map.

i don't completely agree with this formalism because it completely ignores
deconvolution.  again, as i see it, it's a worst case analysis - pathological
source placement and no deconvolution...


	-bryan