pps-analysis-suggests-a-possible-solution-to-the-discrepancy.html

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         title="Permalink to PPS analysis: suggests a possible solution to the discrepancy">PPS analysis: suggests a possible solution to the discrepancy</a></h2>
 
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    <abbr class="published" title="2010-06-21T18:17:00-06:00">
      2010/06/21
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      By <a class="url fn" href="https://keflavich.github.io/blog/author/adam-adamgginsburggmailcom.html">Adam (adam.g.ginsburg@gmail.com)</a>
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    <p>The comparisons I mentioned in the previous post are sort of done.&nbsp; They
are pretty suggestive of a solution to the &quot;flux recovery problem&quot; we
think must be true.&nbsp; However, even if it is a solution, it doesn't
really solve the problem completely.
It looks like v1.0 should be scaled up by a factor of 1.3-1.4 (not
1.5).&nbsp; v2.0 is consistent with the PPS sources to within 5%, and might
even be slightly too high.
The comparison was done by taking the flux in a 60&quot; radius aperture
(equivalent to bolocat 120&quot; diameter apertures) and subtracting off the
background measured in a 120&quot; radius annulus around the source.&nbsp; Without
the background subtraction, these numbers would look very different: in
the science fields, most of the sources sit on an extended background.
Even though the &quot;background flux&quot; isn't recovered in the PPS fields, it
should contribute to the source background because it is involved in the
atmosphere subtraction (it's sort of &quot;already subtracted&quot; so you have to
subtract from the science fields).</p>
<img alt="" src="http://3.bp.blogspot.com/_lsgW26mWZnU/TB-rPT7MLdI/AAAAAAAAFws/7oWTt3FOF-M/s320/BGPS_correction_factors.png" />
<img alt="" src="http://2.bp.blogspot.com/_lsgW26mWZnU/TB-rQId8G_I/AAAAAAAAFw0/NUJKQO_5zI4/s320/BGPS_correction_factor_histograms.png" />
<p>Next step: direct comparison between v1.0 and v2.0.&nbsp; Pixel by pixel,
aperture, and powerspectrum</p>

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