Use the Mauch et al. primary beam correction for mosaicing and primary beam correction

[gigjozsa]

@bnamumba found a significant difference between total HI fluxes of HIPASS sources and total HI fluxes of galaxies detected in a MeerKAT observation and primary-beam corrected using our standard Gaussian. We had a look and the difference might well be due to the fact that the Gaussian is significantly narrower than the Mauch et al. 2019 primary beam found to be more accurate for the MeerKAT primary beam. Therefore, could we implement:

fwhm = 8.783e10/(60.*nu)

            fwhm.resize((basedata.shape[0], 1, 1))
            theta = np.sqrt(datacube)
            # a = (np.cos(1.189*np.pi*(theta/FWHM))/(1-4*(1.189*(theta/FWHM))**2))**2
            datacube = pow((pow(np.cos(1.189*np.pi*(theta/fwhm))/(1-4*pow(1.189*(theta/fwhm),2)),2))/rmsbeam[i],2)

[paoloserra]

@gigjozsa Thanks for taking care of this. Could you please implement it in such a way that we have either a telescope option (e.g., MeerKAT, VLA), or a function option (e.g. gauss, mauch)?

[svw26]

👍 'Gaussian' and 'Mauchian' sounds good to me...! x

[gigjozsa]

Mauchian, that's great. The cos^6 of WSRT would be a "Brouwian"

[dane-kleiner]

Hey @gigjozsa, @paoloserra and I have decided that we need to use the Mauchian primary beam model for our paper, so unless you're (almost) ready to commit the changes, I'm happy to make and implement the changes myself.

[gigjozsa]

@dane-kleiner thank you, please go ahead, I am myself currently busy with #779 in the same context.

[dane-kleiner]

@paoloserra, please have a look at the mauchian branch to see if we can figure out those anomalous pixels before creating a PR.

[paoloserra]

#1215 should have closed this. Mauch et al. (2020) PB now available both in the line and mosaic workers.