Karen O'Neil

Set-up

• L-band
• 50MHz Bandwidth
  
• 8192 channels
  
• 2 Quad
  
• 4 samplers (total)
  
• 1 IF/pol/bank
• 9-level
  
• Linear Polarization
• Observing using position-switching technique

Summary

• Pointing corrections was less than 1'.
• The bandpass shapes and rms levels for the four spectra were virtually identical.
• The determined velocities and fluxes for UGC 9179 agreed, within errors, with those found by Rick Fisher in his Galaxy HI survey
• This mode is ready for observing.

Observations

• Data taken on 26/27 March, 2003
  
• Data file is T_LBAND_26MAR03
  

  Scan	Source	ON time	Comments
  80,81	UGC 9179	300s	RA offset=-87'
  82,83	UGC 9179	300s	RA offset=-87'
  84,85	UGC 9179	300s	RA offset=-87'
  86,87	3C295	300s	RA offset=-87'
  88,89	3C295	300s	RA offset=-87'

Analysis

I. Calibrator - 3C295

Gain inferred from this calibrator was 1.76/1.79 & 1.78/1.80 for pol. X/Y and banks A & B, respectively. Identical gains were found for both On+Off observations. RFI was seen in the calibrator scans every 5MHz. The reduced spectrum are shown below.

Fig 1. 3C295, Bank A, Scans 86/87.

Fig 2. 3C295, Bank B, Scans 86/87.

Fig 3. 3C295, Bank A, Scans 88/89.

Fig 4. 3C295, Bank B, Scans 88/89.

II. Galaxy - UGC 9179

Three 600s positioned-switched observations were made of U9179. All of the on+off pairs showed extremely flat baselines, as shown below:

Fig 5. UGC 9179 in Bank A for scans 80/81.

Fig 6. UGC 9179 in Bank B for scans 80/81.

The measured flux, peak, and velocity widths of UGC 9179 for all of the On+Off pairs fall within 10% of the value published by Rick Fisher for all banks and all polarizations (Flux_obs = 113-116 Jy km/s; Flux_Rick=116 Jy km/s; v_obs = 307 km/s; v_Rick=304 km/s). The average of all 3 scans is below:

Fig 7. Average of all scans for Bank A.

Fig 8. Average of all scans for Bank A.

Fig 9. Average of all scans for Bank B.

Fig 10. Average of all scans for Bank B.

III. RMS

The rms noise for polarizations X and Y ranged from 0.011 - 0.012K, with no discernable difference between the banks or polarizations. The RMS of the three averaged scans, with all IFS averaged, was 7-9 mK for both polarizations. Assuming a Tsys of 17.5K for the two polarizations (taken from the average values) gives a theoretical value of 13 mK for one 600s scan and 8mK for the average of the four scans. The match is quite good.