Difference: SpirePhotometerBeamProfileAnalysis2 (4 vs. 5)

Revision 52015-03-23 - BernhardSchulz

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Figure 3: Difference maps of Neptune and shadow maps for PSW without any correction (left) and with a small shift by 1.8" in spacecraft X-direction and Gaussian smoothing of the shadow map with sigma=0.1" before the subtraction (right).
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With the advent of the shadow maps, previous efforts involving detection and subtraction of point sources, and fitting of a warped background plane, became unnecessary.
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With the advent of the shadow maps, previous efforts involving detection and subtraction of point sources, and fitting of a warped background plane, became unnecessary. Removing the warped plane still gives the best agreement between the radial profiles of three arbitrary sectors chosen around the source, yet lacking a good motivation for either, removal of a warped plane or a flat tilted plane is missing now. The solid angles derived by integrating over the beam profile after removing optimized versions of a warped plane, a flat tilted plane, and a simple median are in Table 2.

  PSW PMW PLW
Removed warped plane 448 800.4 1700.0
Removed flat tilted plane 447.1 801.8 1700.0
Removed median 447.2 800.9 1700.6
Table 2: Variations in integrated solid angle due to different background removal procedures.

The subtraction of the background observations has minimized the differences delivered by these various methods. Thus we choose removing the simple median of all data points outside the 600" radius around the center.

 

Looking for "Triton Contamination"

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Neptune's moon Triton could in principle affect the beam profile by adding flux to one side. Overplotting the positions of Triton during the observational time of all four maps over a contour plot of the reconstructed beam profile reveals no obvious deformation that could have been caused by its Submm emission. The FWHM of the beam is rather more narrow towards the moon's position.
 
Figure 4: Overplot of Triton positions during the observation over PSW isophotes of the Neptune map as thick black trace. The levels are in Jy and the small tick marks on the side are arc seconds.
 
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