Karen O'Neil, Frank Ghigo

Set-up

• L-band
• 12.5MHz Bandwidth
  
• 8192 lags
  
• 1 Quad
  
• 8 samplers
  
• 3-level
  
• Linear Polarization
• Band centers offset by 5 MHZ (IF2=13075,13080,13085,13090)
• Observing using position-switching technique

Summary

• Pointing correction was less than 1'.
• No baseline ripples were seen in either bandpass
• No calibrator source was observed. Gain from the 1N8-0A-12-9 mode (1.72 & 1.82 K/Jy) was used.
• The bandpass shapes and rms levels for the four IFs were virtually identical and equal to the theoretical prediction.
• Due to azimuth restrictions, two galaxies were observed - UGC 9179 and UGC 5572. The determined velocities and fluxes for both galaxies agreed, within errors, with those found by Rick Fisher in his Galaxy HI survey
• No significant RFI was seen, although there was significant ringing in the 1st 200 lags.
• 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
  79,80	UGC 9179	300s	RA offset=-87'
  81,82	UGC 9179	300s	RA offset=-87'
  83,84	UGC 9179	300s	RA offset=-87'
  87,88	UGC 5572	300s	RA offset=-87'
  89,90	UGC 5572	300s	RA offset=-87'
  91,92	UGC 5572	300s	RA offset=-87'

Analysis

I. Calibrator - 3C295

No calibrator was observed. Instead, gain of 1.72 & 1.82 for pol. X & Y, respectively, was taken from the earlier observations of mode 1N8-0A-12-9.

II. Galaxy 1 - UGC 9179

Three 600s positioned-switched observations were made of U9197 before the azimuth track restrictions were reached. 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 all four IFs (and combined with the U5572 observations).

The measured flux, peak, and velocity widths of UGC 9179 falls within the errors of the flux published by Rick Fisher for all IFS and all polarizations. Example spectra are below:

Fig 1. IF1, average of all scans

Fig 2. IF1, scan 80, blown up to see detail in galaxy

III. Galaxy 2 - UGC 5572

Three 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 all four IFs (and combined with the U9179 observations).

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

Fig 3. IF1, average of all scans

Fig 4. IF1, average, blown up to see detail in galaxy

IV. RMS

The rms noise for polarizations X and Y ranged from 27 - 30 mK, with no discernable difference between the four IFs. Assuming a Tsys of 18.4 K for both polarizations (taken from the average values) gives a theoretical value of 30 mK, 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 5. If2, all plots averaged, blown up for baseline details

Other baselines plots available are:

• IF1, all scans averaged, blown up to see detail in baseline
• IF2, scan 80, blown up to see detail in baseline
• IF3, scan 80, blown up to see detail in baseline
• IF4, scan 80, blown up to see detail in baseline
• IF3, all scans averaged, blown up to see detail in baseline
• IF4, all scans averaged, blown up to see detail in baseline

V. Ringing

Signigicant ringing was seen in almost all scans. The ringing occurred in the first 200-300 lags. An example of the ringing is below:

Fig 6. IF1, Scan 80, blown up to show ringing in first 200 lags.