Karen O'Neil

Set-up

• L-band
• 50Hz Bandwidth
  
• 4096 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'.
• All thhe data in bank B (quad 2) has 50MHz ripples which are not present in the bank A data.
• The bandpass shapes and rms levels for the IFs/samplers for each bank were virtually identical.
• The determined velocities and fluxes for UGC 7322 agreed, within errors, with those found by Rick Fisher in his Galaxy HI survey

Observations

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

  Scan	Source	ON time	Comments
  90,91	3C295	300s	RA offset=-87'
  92-95	JUNK
  96,97	UGC 7322	60s	RA offset=-87'
  98,99	UGC 7322	300s	RA offset=-87'
  100,101	UGC 7322	300s	RA offset=-87'
  102,103	UGC 7322	300s	RA offset=-87'
  104,105	UGC 7322	300s	RA offset=-87'

Analysis

I. Calibrator - 3C295

Gain inferred from this calibrator was 1.78/1.81 for pol. X & Y, respectively, for both banks and all samplers. RFI was seen in the calibrator scans every 5MHz. The reduced spectrum are shown below.

Fig 1. 3C295, Bank A, IF 1.

Fig 2. 3C295, Bank A, IF 2.

Fig 3. 3C295, Bank B, IF 1.

Fig 4. 3C295, Bank B, IF 2.

II. Galaxy - UGC 7322

Four 600s positioned-switched observations were made of U7322. For bank A, all the on+off pairs showed extremely flat baselines, as shown below:

Fig 5.UGC 7322 in Bank A, IF1 for scans 98/99.

Fig 6.UGC 7322 in Bank A, IF2 for scans 98/99.

Bank B, however, showed a 40-50 MHz baseline ripple:

Fig 7. UGC 7322 in Bank B, IF1 for scans 98/99.

Fig 8. UGC 7322 in Bank B, IF2 for scans 98/99.

Fig 9. Baseline ripple in Bank B, IF1 for scans 98/99.

Fig 10. Baseline ripple in Bank B, IF2 for scans 98/99.

Fig 11. Baseline ripple in Bank B, IF1 for all scans.

Fig 12. Baseline ripple in Bank B, IF2 for all scans.

The measured flux, peak, and velocity widths of UGC 7322 falls within the errors of the flux published by Rick Fisher for all IFS and all polarizations (Flux_obs = 253 - 263 Jy km/s; Flux_Rick=259 Jy km/s; v_obs = 243 km/s; v_Rick= km/s). The average of all 4 scans is below:

Fig 13. Average of all scans for Bank A, IF=1.

Fig 14. Average of all scans for Bank A, IF=2.

Fig 15. Average of all scans for Bank B, IF=1.

Fig 16. Average of all scans for Bank B, IF=2.

III. RMS

The rms noise for polarizations X and Y ranged from 9 - 12 mK, with no discernable difference between the banks/IFs/samplers. The RMS of the four averaged scans for Bank A was 5 mK for polarizations X and Y and both IFs. The RMS of the four averaged scans for Bank B was 6 mK for polarizations X and Y and both IFs. Assuming a Tsys of 17.5K for the two polarizations (taken from the average values) gives a theoretical value of 9 mK for one 600s scan and 5 mK for the average of the four scans. The match is quite good.