Science Tools Working Group

We met this week and expect to return to an every-other-week schedule for the foreseeable future.

The current version of ScienceTools remains v8r0p4. This should be considered the 'Service Challenge 2' release unless we come up with another name for Service Challenge 2 (like obssim2 or The Empire Strikes Back).

Data products: Jim has implemented the 2 changes to the FT2 FITS specification that came out of the Pointing and live time history discussion.

Databases and related utilities

No news. It looks like for SC2 we'll have the FT1 data available from both the GSSC data server (Tom S.) and the Astro Data Server at SLAC (Tony). For ASP testing, it also will be ingested (most likely as orbit-sized 'runs') into the Data Catalog at SLAC (also Tony).

Likelihood analysis

Jim reports that he has made gtfindsrc more robust against the rare circumstance that the likelihood surface near maximum has a jump in it that otherwise stalls the amoeba search algorithm.

Work is still continuing on understanding the differences in results (parameter values and TS values) between binned and unbinned likelihood analyses. Contributors include Jim, Vincent Le Biez, Florian Kraft, Benoit, Jean, Ludovic, Toby, and Vincent Lonjou. Space does not permit an adequate summary here. The likelihood Test Statistic values for unbinned analysis are coming out significantly less than for binned analysis, a factor of ~1.4, increasing (or possibly not) with decrease source flux. There's some prejudice to believing the binned TS values, possibly because they are larger. The fluxes reported by unbinned likelihood may (or might not) be slightly biased on the low side. I'm trying to give the impression here that we are getting somewhere but still getting there.

GRB tools

Jim reported a problem with the gtrspgen - actually from Nicola and Nukri - that has to do with getting an exception from the integrator (dgauss8) for the energy dispersion. This is in a part of the code that is checking accuracy and seems to get hung up way out in the tails (e.g., at ~16 GeV when the central energy for a convolution was 160 MeV). Jim thinks that a workaround can be implemented via the irfs package, where the energy dispersions are looked up.

Pulsar tools

James reports that he and Masa are working on consolidating the base classes in the pulsar tools and should have this done by the end of the current build cycle (~1 week from now). This will allow the planned barycenter-on-the-fly feature to be implemented in a relatively straightforward way.

Observation simulation

James reports that Richard ran into a segmentation fault problem with the microquasar source, which was traced to it trying to query for events after the last source gave its last photon. Jim and Toby helped to sort out the resolution.

User interface and infrastructure (& utilities)

James reports that at the GSSC they are working on the HEASARC aspects of the build system for the science tools (for when they get into the business of supporting and delivering the science tools for guest investigators. Larry Brown had made a lot of progress toward automatically getting the science tools built using the HEASARC's hmake - involving parsing CMT requirements files. If we do away with CMT, as seems fairly likely, their Perl scripts presumably will need updating, and some care will need to be taken to minimize the effect of the change from the perspective of getting the tools to build under hmake. Jim and James are going to consult about this.

James has been in communication with the developers of ds9 regarding the possibility of modifying ds9 to make proper region-of-interest selections (that could then be passed back to something like ModelEditor. It isn't an easy problem.

Dave Davis posted proposed name changes for some of the science tools that came out of the discussions at the GSSC-LAT Science Tools Meeting at SLAC, April 2007. He's requesting feedback in the next week. The new names are in general shorter and more uniform; yes, we're keeping 'gt'. For a couple of the tools, 2 possible new names are proposed.

Source Catalog

Did not meet this week.

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