Karen O'Neil

Set-up

• L-band
• 12.5MHz Bandwidth
  
• 8192 channels
  
• 2 Quad
  
• 8 samplers (total)
  
• 2 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
• The first pair of scans for these observations has rms noise 2x the theoretical value. All ofther scans were fine.
• 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
  34,35	UGC 9179	300s	RA offset=-87'
  36,37	UGC 9179	300s	RA offset=-87'
  38,39	UGC 9179	300s	RA offset=-87'
  40,41	UGC 9179	300s	RA offset=-87'
  42,43	UGC 9179	300s	RA offset=-87'
  44,45	3C295	300s	RA offset=-87'

Analysis

I. Calibrator - 3C295

Gain inferred from this calibrator was 1.95 & 1.87 for pol. X & Y, repectively, on both banks. RFI was seen in the calibrator scans every 5MHz. The reduced spectrum are shown below.

Fig 1. 3C295, Bank A, Scans 44/45.

Fig 2. 3C295, Bank B, Scans 44/45.

II. Galaxy - UGC 9179

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

Fig 3. UGC 9179 in Bank A for IF1, scans 34/35.

Fig 4. UGC 9179 in Bank A for IF2, scans 34/35.

Fig 5. UGC 9179 in Bank B for IF2, scans 34/35.

Fig 6. UGC 9179 in Bank B for IF2, scans 34/35.

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 = 98-117 Jy km/s; Flux_Rick=116 Jy km/s; v_obs = 308 km/s; v_Rick=304 km/s). The average of the four good scans (not including the first On+Off pair) scans is below:

Fig 7. Average of all good scans for Bank A, IF1.

Fig 8. Average of all good scans for Bank A, IF2.

III. RMS

Ignoring the first On+Off pair, the rms noise for polarizations X and Y ranged from 0.024 - 0.026K, with no discernable difference between the banks or polarizations. The RMS of the three averaged scans, with all IFS averaged, was 12-13 mK for both polarizations. Assuming a Tsys of 18K for the two polarizations (taken from the average values) gives a theoretical value of 27 mK for one 600s scan and 14mK for the average of the four scans. The match is quite good.