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3mm Testing in July 2001 Tony Wong ATNF Epping CA Forum, 6 Sep.

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Presentation on theme: "3mm Testing in July 2001 Tony Wong ATNF Epping CA Forum, 6 Sep."— Presentation transcript:

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

3 3c279 128 MHz 64 chans Bandpass at 90.68 GHz

4 After bandpass calibration applied Bandpass at 90.68 GHz

5 Phase/amp stability at 90 GHz  RMS  10  but amplitude variations much greater!

6 Phase/amp stability at 90 GHz Phase cycles every  20 minutes

7 Phase/amp stability at 22 GHz Amps decreasing - worsening weather?

8 How often to calibrate? 5 min on 3c279: 10% amp fluctuation,  RMS  15 

9 System Temperatures T sys, 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.

10 System Temperatures Same observation for 87-91 GHz.

11 System Temperatures Since the “psJy” scale is derived assuming constant GT sys of 500 Jy, the visibility amplitude in psJy is anticorrelated with T sys.

12 Sensitivity Estimate, 86 GHz Assuming a flux of 8 Jy for Uranus, the observed amplitude and T sys give the geometric mean Jy/K for the two antennas.

13 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.

14 Some Science Results Molecules in IRC+10216 HCN HNC C3NC3N SiS

15 Some Science Results Dense Gas in the LMC HCN HCO + Thermal SiO in N6334 W 17.5” center


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