Bandpass shape not flat after mfcal - interference?

Got a calibration problem? Discuss it here.

Moderator: Mark.Wieringa

Bandpass shape not flat after mfcal - interference?

Postby danieljohansson » Fri Mar 11, 2011 8:41 pm

Hi,
Sorry for asking a possibly simple question, but I have been struggling with this for a few days and none of my colleagues seem to know the answer.

I'm reducing 7mm data at 30.5 GHz, and I'm having some problems with the bandpass calibration. I used the source 0537-441 as bandpass-calibrator (flux density ~10 Jy @ 30 GHz).

I have attached the before and after-bandpass calibrator diagrams from uvspec to this message.

I perform the bp-cal with mfcal, stokes=xx,yy . The band is almost flat, but there are some "wiggles" at the 5% level, as well as a slope to some of the baselines. In the final spectra on my science target I can see wiggles too, perhaps coming from the bandpass shape.

Here is how the bp-cal looks in pgflag for the 1-3 baseline.
pgflag_bl13.jpg
pgflag display for the 1-3 baseline
pgflag_bl13.jpg (258.52 KiB) Viewed 41806 times


These lines may be the reason for the bandpass shape. What can I do to improve?

Cheers!
Daniel
Attachments
before_after_mfcal.zip
Bandpass calibrator before and after mfcal as two pdf's
(920.19 KiB) Downloaded 9842 times
danieljohansson
 
Posts: 3
Joined: Mon Jan 24, 2011 11:07 pm

Return to Calibration

Who is online

Users browsing this forum: No registered users and 1 guest

cron