3mm Testing in July 2001

1
3mm Testing in July 2001

• Tony Wong
• ATNF Epping
• CA Forum, 6 Sep

2
Bandpass at 90.56 GHz

• 3c279
• 128 MHz
• 64 chans

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Bandpass at 90.68 GHz
3c279 128 MHz 64 chans
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Bandpass at 90.68 GHz
After bandpass calibration applied
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Phase/amp stability at 90 GHz

• ?RMS ? 10?
• but amplitude variations much greater!

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Phase/amp stability at 90 GHz

• Phase cycles every ?20 minutes

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Phase/amp stability at 22 GHz

• Amps decreasing- worsening weather?

8
How often to calibrate?

• 5 min on 3c279
• 10 amp fluctuation, ?RMS ? 15?

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System Temperatures

• Tsys, corrected for atmospheric absorption, was
  determined using the paddle while stepping in
  frequency from 84-87 GHz.
• Some of the frequency variation may be due to
  varying atmosphere.

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System Temperatures

• Same observation for 87-91 GHz.

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System Temperatures

• Since the psJy scale is derived assuming
  constant GTsys of 500 Jy, the visibility
  amplitude in psJy is anticorrelated with Tsys.

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Sensitivity Estimate, 86 GHz

• Assuming a flux of 8 Jy for Uranus, the observed
  amplitude and Tsys give the geometric mean Jy/K
  for the two antennas.

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Sensitivity Estimate, 90 GHz

• Note strong RFI at 88.160 GHz. Significant RFI
  is also found at 88.000 and 88.320 GHz, weaker at
  88.240 GHz.

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Some Science Results

• Molecules in IRC10216

HCN
C3N
HNC
SiS
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Some Science Results

• Dense Gas in the LMC

Thermal SiO in N6334
HCN
center
HCO
W 17.5