15mm calibration question
Posted: Mon Feb 15, 2016 3:46 pm
Hi all,
I've got another calibration recipe regarding some 15mm data I got recently. The data, in a nut shell, visited a number of sources, each with their own phase calibrator. One of the sources had 1934 as its phase calibrator, and another, by dumb luck, had 0537-441 as its phase calibrator. I observed 0537-441 at the start of the run to calibrate the array and acquire a bandpass solution (observed for 10 minutes; other sources weren't up yet). I also got 10 minutes on 1934 at the end of the run to establish a good flux density scale.
Since mfcal assumes a flat spectrum when determining the bandpass solution for sources other then 1934, extra steps should be performed to ensure that the flux scaling is as good as it can be. Reading the ATCA user manual and the ATCA Calibration database page, the approach I've taken is: mfcal/gpcal 0537, gpcopy the bandpass solution to 1934, gpcal 1934, gpboot the calibration solutions back to 0537-441, use uvfmeas to obtain an mfcal flux model and re-calibrate (mfcal/gpcal) 0537-441. At this point 0537-441 should have both a correct bandpass calibration and have a bootstrapped flux density scale.
I was hoping to confirm that once the above procedure has been complete, I can gpcopy 0537-441 to other phase calibrators (since it has both the bandpass and flux scale) and proceed as normal. I'm worried I have misunderstood something along the way and the approach isn't correct, especially since both 0537 and 1934 have been used as phase calibrators. Attached is the complete reduction I've outlined above as well as the uvfmeas fits - before and after the user supplied flux model in mfcal.
Thanks,
Tim
I've got another calibration recipe regarding some 15mm data I got recently. The data, in a nut shell, visited a number of sources, each with their own phase calibrator. One of the sources had 1934 as its phase calibrator, and another, by dumb luck, had 0537-441 as its phase calibrator. I observed 0537-441 at the start of the run to calibrate the array and acquire a bandpass solution (observed for 10 minutes; other sources weren't up yet). I also got 10 minutes on 1934 at the end of the run to establish a good flux density scale.
Since mfcal assumes a flat spectrum when determining the bandpass solution for sources other then 1934, extra steps should be performed to ensure that the flux scaling is as good as it can be. Reading the ATCA user manual and the ATCA Calibration database page, the approach I've taken is: mfcal/gpcal 0537, gpcopy the bandpass solution to 1934, gpcal 1934, gpboot the calibration solutions back to 0537-441, use uvfmeas to obtain an mfcal flux model and re-calibrate (mfcal/gpcal) 0537-441. At this point 0537-441 should have both a correct bandpass calibration and have a bootstrapped flux density scale.
I was hoping to confirm that once the above procedure has been complete, I can gpcopy 0537-441 to other phase calibrators (since it has both the bandpass and flux scale) and proceed as normal. I'm worried I have misunderstood something along the way and the approach isn't correct, especially since both 0537 and 1934 have been used as phase calibrators. Attached is the complete reduction I've outlined above as well as the uvfmeas fits - before and after the user supplied flux model in mfcal.
Thanks,
Tim
Code: Select all
# CALIBRATE BANDPASS
#—————————————————
Task: mfcal
vis = 0537-441.17000/
line =
stokes =
edge =
select =
flux =
refant =
minants =
interval = 0.1
options =
tol =
Task: mfcal
vis = 0537-441.21000/
line =
stokes =
edge =
select =
flux =
refant =
minants =
interval = 0.1
options =
tol =
#—————————————————
# CALIBRATE GAINS
#—————————————————
Task: gpcal
vis = 0537-441.17000/
select =
line =
flux =
spec =
refant =
minants =
interval = 0.1
nfbin = 2
tol =
xyphase =
options = xyvary,qusolve
Task: gpcal
vis = 0537-441.17000/
select =
line =
flux =
spec =
refant =
minants =
interval = 0.1
nfbin = 2
tol =
xyphase =
options = xyvary,qusolve
#—————————————————
# COPY TO FLUX CALIBRATOR
#—————————————————
Task: gpcopy
vis = 0537-441.17000/
out = 1934-638.17000/
mode =
options =
Task: gpcopy
vis = 0537-441.21000/
out = 1934-638.21000/
mode =
options =
#—————————————————
# CALIBRATE GAINS OF PRIMARY
#—————————————————
Task: gpcal
vis = 1934-638.17000/
select =
line =
flux =
spec =
refant =
minants =
interval = 0.1
nfbin = 2
tol =
xyphase =
options = xyvary,qusolve,nopol
Task: gpcal
vis = 1934-638.21000/
select =
line =
flux =
spec =
refant =
minants =
interval = 0.1
nfbin = 2
tol =
xyphase =
options = xyvary,qusolve,nopol
#—————————————————
# BOOTSTRAP FLUX
#—————————————————
Task: gpboot
vis = 0537-441.21000/
cal = 1934-638.21000/
select =
Task: gpboot
vis = 0537-441.21000/
cal = 1934-638.21000/
select =
#—————————————————
#—————————————————
bandpass-1.eps made here
MFCAL flux=3.8843, 17.0,-0.3042
#—————————————————
# CALIBRATE BANDPASS WITH MODEL
#—————————————————
Task: mfcal
vis = 0537-441.17000/
line =
stokes =
edge =
select =
flux = 3.8843,17.0,-0.3042
refant =
minants =
interval = 0.1
options =
tol =
Task: mfcal
vis = 0537-441.21000/
line =
stokes =
edge =
select =
flux = 3.8843,17.0,-0.3042
refant =
minants =
interval = 0.1
options =
tol =
#—————————————————
# REDO GAIN CALIBRATION
#—————————————————
Task: gpcal
vis = 0537-441.17000/
select =
line =
flux =
spec =
refant =
minants =
interval = 0.1
nfbin = 2
tol =
xyphase =
options = xyvary,qusolve
Task: gpcal
vis = 0537-441.21000/
select =
line =
flux =
spec =
refant =
minants =
interval = 0.1
nfbin = 2
tol =
xyphase =
options = xyvary,qusolve
#—————————————————
#—————————————————
bandpass-2.eps made here
#—————————————————