Changes between Version 22 and Version 23 of Notes/ExampleReduction

Timestamp:

03/31/09 15:32:18 (15 years ago)

Author:

JamieStevens

Comment:

--

Notes/ExampleReduction

@@ -321 +321 @@
 images, and this is because the primary beam of the antenna gets smaller with increasing frequency.
 
+So we can compare these results with the other methods of imaging, we make some rough measurements of flux of each source.
+According to NED, SUMSS J054003-663939 has a flux of 1.27 mJy at 843 MHz, and SUMSS J054125-664307 has a flux of 0.94 mJy
+at 843 MHz.
+
+We get our fluxes using kvis, by taking the sum of the flux in 9 pixels (3x3) centred on the brightest pixel of each source.
+This should be approximately 1 beam, so we can normalise the flux in the images. The table below shows how the flux of the
+sources varies with frequency. Note that at a frequency of 5692 MHz the sources are right on the edge of the image, so
+no measurements are done at frequencies higher than this.
+
+|| Central Freq (MHz) || J054003-663939 || J054125-664307 ||
+|| 4540               || 1.0 +- 0.2     || n/a            ||
+|| 4668               || 1.0 +- 0.2     || 1.0 +- 0.2     ||
+|| 4796               || 1.1 +- 0.3     || 1.0 +- 0.3     ||
+|| 4924               || 1.1 +- 0.4     || 0.8 +- 0.4     ||
+|| 5052               || n/a            || 1.3 +- 0.3     ||
+|| 5180               || 1.0 +- 0.4     || n/a            ||
+|| 5308               || 1.2 +- 0.4     || 1.2 +- 0.4     ||
+|| 5436               || 1.6 +- 0.3     || 1.2 +- 0.3     ||
+|| 5692               || 1.2 +- 0.4     || 0.9 +- 0.4     ||
+
+The sources don't appear to vary in flux much with frequency, at least within the errors of measurement. That would
+suggest that using mfclean instead of clean might not produce a different result.