ISSI Workshop 2016 April: Task List

(First person named usually indicates the lead.)

Table of Contents

A. Website.

  • (VK): Collect all presentations from April 2016 meeting and upload to Team website.
  • (VK): Obtain meeting notes from MW and upload to Team website.
  • (VK): Obtain list of action items from MW and upload to Team website.

B. Meeting notes.

  • (MW; VK HWK): Produce meeting notes and provide them to VK for upload to Team website.
  • (MW; VK, HW): Produce list of action items and provide them to VK for upload to Team website.

C. Fe-solar-moss paper.

  • The skeleton of the paper is available on Overleaf.

    • Read-only web link: (Check for 2016-Apr-23 email from HW with the read/write link.)
    • A few comments have been added on the intended content for each section.
  • Writing assignments:

    • (HW): Introduction
    • (GDZ): Uncertainties in the Atomic Data
    • (NS/DVD/DS): Inference
    • (HW/FR): Test Cases
    • (GDZ/HW): EIS Observations
    • (AF/CB): Covariance Structure
    • (HW): Discussion of Future work
    • (HW): Conclusions
  • (HW/NS): Test case #1: Blind test with specific ne, ds, with default CHIANTI model.

    • Should get back the CHIANTI default model as the most preferred one. Also try other curves to compute the intensities and see if these can also be recovered.
  • (HW/NS): Test case #2: Use FR's MHD model to blind test the solver.

    • This is a good thing to try, because (a) we have T info, and (b) the model has very different ne, ds pairs than what we were getting out of the EIS observations.
    • We must be very careful to see how well we recover the right results on the MHD model before we commit to including the results in the paper. Refer to the Testa et al. paper where they did something similar with IRIS models, and their results suggest it is not possible to meaningfully do those inversions.
    • We want to do some sort of goodness of fit check of the parameter estimates (ne, ds) to see how well they predict the data. This is complicated since the errors on the atomic models are folded in.
    • (HW; FR): Compute Fe XIII moss intensities from simulation result. Use as a test case for the analysis.
  • (DS; NS): There are still a handful of cases that are causing problems with the Hessian calculations, but working on that. But after that, the codes will be uploaded to the repository.

  • (HW): Check that all 10^6 combinations have LS solutions.

  • (DVD/NS/DS/JC): How does the data analyst extract the "best" (ne, ds) solution from the posteriors? What is "the" solution they should put into their analysis?

  • (MW; HW) How well do the "best" (ne, ds) solutions fit the data?

  • (HW; GDZ): Add Fe XIII 196.5 and 209.6 A lines to the list of intensities.

  • (HW; GDZ): Add EIS data from 20061225_225013.

    • Recompute perturbed atomic data assuming >5% and save seeds or rates.
    • Compute LS fits to all combinations of intensities and curves.
    • Run DS/NS routines to find results from Pragmatic Bayes and Full Bayes.

D. O-Capella-DEM paper.

  • (VK): Track paper development. Put outline into Overleaf and update periodically.

  • "Paper" needs more foundation work, with the following items still in an

    ambiguous state:

    • (VK; DvD) the statistical model that determines the likelihood of the data given the DEM model needs further thought. There are two options: Poisson likelihood over microbins, or sampling from predicted spectral profile.
    • (VK; CG, FA) Figure out a set of useful and convenient DEM parameterizations.
    • (VK; AF, GDZ) Figure out how and whether to include ion fraction uncertainties.
    • (CB; AF, VK) Run a large number of atomic data replicates for O VII lines.
    • (GDZ; VK, HW) CB's method does not work for O VIII. For that, use GDZ+HW method to obtain replicates.
    • (JC; VK) Explore ABC as a way to apply smooth spline modifications to nominal Capella DEM.
    • (DvD/JC/DS/NS; VK) Adapt codes to allow for vector temperatures.
    • (VK; GDZ, AF, CB) If we are forced to expand beyond the set of O VII and O VIII lines, which lines should we include?

E. Connor's work on varying fundamental quantum numbers.

  • (GDZ; HW): Provide to CB list of transitions and their wavelength windows (or variances).
  • (CB): Implement a two-stage process that rejects samples that vary in wavelength too much.
    • An alternative approach wherein Connor would introduce an intermediate step that keeps all samples but forces transition wavelengths into their windows was discouraged because it introduces inconsistencies and because then "the A-values do not form a representative sample".

F. Adam looking for correlations in Connor's runs.

  • (AF; CB): Build a covariance matrix using CB's calculations and use a multivariate Normal to draw random samples in the HW/GDZ way.

G. Look at "Loci-like" (ne, ds) curves for 5x EIS Fe XIII lines.

  • This was requested by FR.
  • (HW): Two ways to go at this: a) Show a table of observed and modeled intensities and the best-fit ne and ds; b) Showing these curves of EM = I/eps(T,n) as a function of n, with the locus representing the solution.

H. Addressing the "10,000 km thick moss".

  • (HW; MW, FR): Figure out discrepancy in solutions showing ds ~ 10,000 km.
    • It was observed in the meeting that the ds posteriors are not consistent with physical expectations. Also, Fabio's model confirms a TR thickness of maybe a ~few thousand km.
    • We should compare with a simple 1D model result.

I. CfA meeting in Autumn 2016.

  • (MW; VK, AF) Coordinate for best dates.
  • (MW; VK, AF) Reserve local resources.