Green Bank Telescope - NGC5044 HI observation 2020

We have successfully completed 2 sessions observations on NGC5044, total observing time is 6 hours.

Primary calibrator: 3C286

L-band pointing calibrator used : 1320+1743, and 1311-2216

Off-position : 13:17:47 -15:47:08

1st session : 30 Apr 23:45 ET - 1 May 2:45 ET

2nd session : 1 May 23:45 ET - 2 May 2:45 ET

For the first session: we have completed 42 pairs of OnOff scans on NGC5044, total on target time is 63 mins. Second session, we have 43 pairs, total 64.5 mins on target. Two sessions resulted in 127.5 mins observation on target.

Weather during both observations were good, cloudy and temp at few degree Celsius, wind is below 10 mph.

In both sessions, pointing and focusing solution are good as verified by the operator.

For second session:

Within 1.401 - 1.415 GHz, i.e. -1500 to 1500 km/s , there are two RFI in Y polarisation. one at -582 km/s (1.41 GHz) and another at -160 km/s (1.408GHz) as shown in the figure below

During the observation, only 1 scan is problematic, scan 25 of second session as shown in the figure below. It was caused by lower counts in the on-subscan, hence this on-off pair must be disregarded. This occurs in both polarisation.

Figure below shows the pale blue box indicating the region to fit for baseline , the white curve shows the shape of the baseline fitted.

After the baseline subtraction

smooth to 20 km/s:

For the first session:

only the -582 km/s RFI is present. There are no apparent bad scans.

Result is very similar to the second session.

Combining both observations