Karen O'Neil, Frank Ghigo

Set-up

• L-band
• 12.5MHz Bandwidth
  
• 8192 lags
  
• 2 Quad
  
• 4 samplers
  
• 9-level
  
• Linear Polarization
• Band centers offset by 5 MHZ (IF2=13075,1380)
• Observing using position-switching technique
• DCR was on simultaneously during observations (on accident)

Summary

• Pointing correction was less than 1'.
• No baseline ripples were seen in either bandpass
• The bandpass shapes and rms levels for the two IFs were virtually identical and equal to the theoretical prediction.
• The determined velocities and fluxes for UGC 5572 agreed, within errors, with those found by Rick Fisher in his Galaxy HI survey
• No significant RFI was seen.
• Ringing was seen in the first 200 channels of most scans.
• DCR did not appear to affect observations
• This mode is ready for general use.

Observations

• Data taken on 19 Feb, 2003
  
• Data file is T_LBAND_19FEB03
  

  Scan	Source	ON time	Comments
  99,100	UGC 5572	600s	RA offset=-87'
  101,102	UGC 5572	300s	RA offset=-87'
  103,104	UGC 5572	300s	RA offset=-87'
  105,106	UGC 5572	300s	RA offset=-87'
  107,108	UGC 5572	300s	RA offset=-87'

Analysis

I. Calibrator

No calibrator source was observed. A gain of 1.72 & 1.82 for pol. X & Y, respectively, was used (taken from 3C295 observations taken the same night in different modes).

II. Galaxy - UGC 5572

One 1200s and four 600s positioned-switched observations were made of U5572. Unfortunately, the 5MHz shift between IFs resulted in the source not lying in the band for any but the 1st IF. Rms calculations, though, could be done for both IFs.

The measured flux, peak, and velocity widths of UGC 5572 falls within the errors of the flux published by Rick Fisher for IF1 and both polarizations. Example spectra are below:

Fig 1. IF1, average of all scans

Fig 2. U5572, IF1, scan 100

III. RMS

The rms noise for polarizations X and Y was 0.018 for the 1200s scans, and ranged from 0.026 - 0.034 for the 600s scans. No discernable difference was seen between the two IFs. Assuming a Tsys of 18.9 K for both polarizations (taken from the average values) gives a theoretical value of 0.29 mK (for the 600s observations), in good agreement with the measured values. The RMS of the averaged scans also followed the thoeretical 1/(sqrt(t) behavior as the scans were averaged. Plots of the baselines are below.

Fig 3. If1, all plots averaged, blown up for baseline details

Fig 4. IF2, averaged over all scans, blown up to see detail in baseline