33GHz flux discrepancy
Posted: Wed Aug 14, 2019 1:02 pm
Hi,
I've reduced 7mm observations (6A config) and have attempted to image the result. The obs had nice weather with an average seemon rms of 150. Before I uvcat the 33GHz and 35GHz vis files into a 34GHz file I image each separately. For natural weighting, the 35GHz vis data produces an expected image with an rms of 1.74348E-05 and maximum value of 8.898955E-05 (using histo on restors output) however, the 33GHz vis data has an rms of 9.18948E-03 and a maximum value of 2.978523E-02. This is discrepancy is similar with each respective image, the 35GHz shows an expected image with an elongated beam (attached) whereas, the 33GHz image displays diagonal bands (attached). Obviously then once I uvcat the vis files into 34GHz the 33GHz values dominate over the 35GHz readings and my image is full of diagonal bands.
My reduction steps are as follows:
(1) mfcal on the bpcal with int=0.1
(2) gpcopy (1)'s sol onto the phase cal and flux cal
(3) mfcal on the flux cal with int=0.1 and options=nopassol
(4) mfcal on the phase cal with int=0.1 and options=nopassol
(5) gpboot phasecal with flux cal
(6) gpcopy (5)'s sol onto the targets
My images steps are as follows:
(1) invert with imsize=3,3,beam cell=5,5,res sup=$sup options=mfs,double
(2) clean with cutoff=5*rms
(3) restor
and cgdisp to view
This target has been previously imaged "nicely" at 34GHz (attached) and I'm unsure why I'm getting this large readings for the 33GHz vis files. Any suggestions?
Thanks,
Brodie
I've reduced 7mm observations (6A config) and have attempted to image the result. The obs had nice weather with an average seemon rms of 150. Before I uvcat the 33GHz and 35GHz vis files into a 34GHz file I image each separately. For natural weighting, the 35GHz vis data produces an expected image with an rms of 1.74348E-05 and maximum value of 8.898955E-05 (using histo on restors output) however, the 33GHz vis data has an rms of 9.18948E-03 and a maximum value of 2.978523E-02. This is discrepancy is similar with each respective image, the 35GHz shows an expected image with an elongated beam (attached) whereas, the 33GHz image displays diagonal bands (attached). Obviously then once I uvcat the vis files into 34GHz the 33GHz values dominate over the 35GHz readings and my image is full of diagonal bands.
My reduction steps are as follows:
(1) mfcal on the bpcal with int=0.1
(2) gpcopy (1)'s sol onto the phase cal and flux cal
(3) mfcal on the flux cal with int=0.1 and options=nopassol
(4) mfcal on the phase cal with int=0.1 and options=nopassol
(5) gpboot phasecal with flux cal
(6) gpcopy (5)'s sol onto the targets
My images steps are as follows:
(1) invert with imsize=3,3,beam cell=5,5,res sup=$sup options=mfs,double
(2) clean with cutoff=5*rms
(3) restor
and cgdisp to view
This target has been previously imaged "nicely" at 34GHz (attached) and I'm unsure why I'm getting this large readings for the 33GHz vis files. Any suggestions?
Thanks,
Brodie