Checkout: A:1N2-0A-12-9, B:1N2-1B-12-9

Checkout of spectrometer mode A:1N2-0A-12-9, B:1N2-1B-12-9
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Karen O'Neil

Set-up

L-band
12.5MHz 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
46,47	3C295	300s	On+Off, RA offset=-87'
48,49	UGC 9179	300s	RA offset=-87'
50,51	UGC 9179	300s	RA offset=-87'
52,53	UGC 9179	300s	RA offset=-87'
54,55	UGC 9179	300s	RA offset=-87'

Analysis

I. Calibrator - 3C295

Gain inferred from this calibrator was 1.97/1.93 & 1.98/1.91 for pol. X/Y and banks A & B, respectively. RFI was seen in the calibrator scans every 5MHz. The reduced spectrum are shown below.

Fig 1. 3C295, Bank A

Fig 2. 3C295, Bank B

II. Galaxy - UGC 9179

Four 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 scans 48/495.

Fig 4.UGC 9179 in Bank B for scans 48/495.

The measured flux, peak, and velocity widths of UGC 9179 for all of the On+Off pairs falls within the errors of the flux published by Rick Fisher for all banks and all polarizations (Flux_obs = 100-110 Jy km/s; Flux_Rick=116 Jy km/s; v_obs = 307 km/s; v_Rick=304 km/s). The average of all 4 scans is below:

Fig 5. Average of all scans for Bank A.

Fig 6. Average of all scans for Bank A.

Fig 7. Average of all scans for Bank B.

Fig 8. Average of all scans for Bank B.

III. RMS

The rms noise for polarizations X and Y ranged from 0.024 - 0.025K, with no discernable difference between the banks or polarizations. The RMS of the four averaged scans, with all IFS averaged, was 12 mK for both polarizations. Assuming a Tsys of 17.5K 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.