Changes between Version 8 and Version 9 of IPP_Progress_Report_20100927

Timestamp:

Oct 6, 2010, 8:51:33 AM (16 years ago)

Author:

eugene

Comment:

--

IPP_Progress_Report_20100927

@@ -5 +5 @@
 
 === Eugene Magnier ===
+
+ I spent the week at Harvard for the 'photfest'.  This involved folks from 
+both the CfA/JHU transient team and the QUB transient team.  We had a specific 
+set of skycells from MD07 and MD08 with known events.  I generated new nightly 
+stacks, and ran the difference images for those stacks against an appropriate 
+reference stack.  Mark Huber ran the photpipe code to generate difference images 
+as well, and we spent the week comparing the results.  
+
+The most important result from 'photfest' was that the CfA/JHU group 
+are now willing to use at least the IPP-produced difference image pixels, if we set
+the Medium Deep nightly stack-stack diffs to use SINGLE direction convolution on the reference stack. 
+We agreed that this produces results essentially 
+indistinguishable from the photpipe difference image analysis.  They
+also convinced me that, for the stack-stack diffs where we have a deep
+reference stack, it is OK to always choose the deep reference
+stack as the convolution target -- the occasional instances of small
+amounts of de-convolutions are acceptable given the high S/N of the
+reference stack and the over-sampling.  
+
+We also agreed that the IPP-produced detection lists are close to ready (and may already
+be acceptable), but that more tests need to be made of the false-positive rates (after 
+appropriate exclusions are applied) and the false negative rates.
+
+We (mostly they -- Mark Huber, Micheal Wood-Vasey, and Ken
+Smith) are looking at the detections produced by the IPP, along with
+the feedback I gave them on the flags and exclusions, to see if (with
+appropriate filtering) the false positives and false negatives are
+acceptable and if the photometry is is consistent with the photpipe
+equivalent.  The quick look at the last point was positive, but they
+are doing more checks on this.  Mark Huber has promised a report on 
+the conclusions of 'photfest'.
+
+We also agreed that the DUAL
+convolution is at worst equivalent to an optimal SINGLE convolution
+plus an additional smoothing, and it may be the case that the DUAL
+convolution is acceptable or can be made acceptable.  I am going to continue 
+work on this for the near term.
+
+I also worked closely with Eddie Schlafly to bring up up to speed on 
+the issues related to the star/galaxy/cosmic-ray separation process.  
+He is using exposures with good SDSS overlap to explore the application 
+of the various measurements available (moments, various fluxes) to improve 
+the star/galaxy/cosmic-ray identifications.
 
 === Serge Chastel ===