p2111: looking at bursts from 4 objects

dec08

Intro:

p2111 used the 800 MHz mode of the wapps to monitor bursts from a 4 objects. The datataking setup was:

use the wapp spectrometer with 100 MHz bw/band, 3 level sampling, 2048 channels, full stokes. The data was sampled at 1 second intervals.
Do a 15 second cal on , 15 second cal off 12 seconds of time from the source then track the source for 600 seconds. The cycle took about 667 seconds.

The data processing was:

Input the cal scan, data scan and convert them from cross correlations to uncorrected stokes.
Create an rfi mask for the cal using calOn/caloff (this removes the bandpass). Use corblauto to excluse channels that are more than 3 sigma from the mean.
Call the corstokes to scale to kelvins with the cals and then phase correct the signal path using the cal data (hi correlated cal). There was no mueller matrix correction since the matrix we have is out of date.
Convert the data from Kelvins to Janskys using the gain curve for cband.
Computing the total power.

We have and array of 2048 channels by 600 seconds. Use corrms() (rms/mean along each chan) to make a mask where there is no rfi. Average the good chanels to get the total power.

Plotting the data:
For each source as set of plots were made:

IQUV, vs data sample and frequency band.

The horizontal axis is data sample (1 second). I have left out the 67 second gaps between each 10 minute dataset. The vertical axis is milliJy.
There are 8 frequency bands with 4 per page.
The data is plotted I:page1,2 Q:page3,4,U:page5,6, V:page7,8.
Red vertical lines are drawn at the start of each 10 minute dataset.

I data

The median value for I has been removed.
The variation is the za dependence of the gain (the SEFD is higher at large za).

U,V data

Notes:
I'm using positive and negative burst rather the left and rigtht circular. We need to use the heliax in the bowl to see which one comes out where in the data processing.

28dec08(AST)