C2050 G301 Results

G301 (C2050 Candidate)

April 2009

  • Details of observations can be found here
  • G301 was observed at 33/35 GHz, 44/46 GHz, 93/95 GHz
  • Phase calibrator was 1045-62
  • Flux calibrator was Uranus at all frequencies
  • Only including data that was observed between 30 <= elevation <= 90 degrees

Reduction

  • ATLOD
  • UVSPLIT
    • options=nosource
  • UVFLAG
    • for each frequency
    • select=auto / edge=100 / common bad CABB channels
  • UVSPLIT
    • for each frequency
  • MFCAL
    • 1253-055 as bandpass calibrator
    • interval=0.1, refant=2
  • GPCOPY
    • vis=1253-055, out=uranus
  • MFBOOT
    • vis=uranus,1253-055, select=source(uranus), clip=0.5
  • GPCOPY
    • vis=1253-055, out=1045-62
  • MFCAL
    • vis=1045-62, interval=0.1, refant=2, options=nopassol
  • GPBOOT
    • vis=1045-62, cal=1253-055
  • GPCOPY
    • vis=1045-62, out=g301

33/35 GHz

Things don't look promising even at this low frequency, as it looks like this source is resolved. Here is a picture of uvdistance vs amplitude for G301 at 33 GHz:

g301_33ghz_uvdist-amp.png

Looking at the phase calibrator amplitude shows us a more constant flux (as expected), but also that the data quality isn't fantastic. Note that the weather wasn't fantastic either.

1045-62_33ghz_uvdist-amp.png

The data look identical at 35 GHz, which is reassuring.

44/46 GHz

We get much the same results from the 44 GHz data:

g301_44ghz_uvdist-amp.png
1045-62_33ghz_uvdist-amp.png

Unfortunately, a lot of the data from antennas 1 & 3 have lots of bad channels at 46 GHz, and since we're getting less interested in using this source, I don't think it's worth the effort to flag it properly.

93/95 GHz

For some reason we have lost antenna 1 at this frequency, leaving only 4 antenna and 6 baselines.

Also, the phase calibrator 1045-62 is only roughly 0.8 Jy at 3mm, and the phase accuracy isn't very good in these observations. The closure phase rms value is 32.172 degrees, whereas the theoretical value for these observations is 4.887 degrees.

Looking at the amplitudes of the data and the uvdistance vs amplitude plots as before:

g301_93ghz_uvdist-amp.png
1045-62_93ghz_uvdist-amp.png

Something is wrong with this data, but it's hard to figure out what exactly. After some communication with Kate Brooks, I reckon it is that we weren't using the paddle scan enough and the gains were inconsistent across the observation. I doubt that any of the 3mm data from April will be useful at all.

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