propagating atomic uncertainties into data analysis – Kang et al., 2004, XDAP fitting DEMs to high-resolution Chandra and EUVE grating spectra – wavelength errors, missing lines – correlated uncertainties (via MCMC) pre-compute tables of plausible ion balance Vinay Kashyap, SAOHMI/AIA Science Teams Meeting, Monterey, Feb 2006

DEM reconstruction cannot be a black box – fast, simple, robust: pick one – smoothing: a necessary evil – error bars.. bands.. bundles.. ropes – astrophysical limitations: changing densities and abundances flows and non-equilibrium ionization line opacities atomic data errors Vinay Kashyap, SAOHMI/AIA Science Teams Meeting, Monterey, Feb 2006

DEM reconstruction cannot be a black box – fast, simple, robust: pick one – smoothing: a necessary evil – error bars.. bands.. bundles.. ropes – astrophysical limitations: changing densities and abundances flows and non-equilibrium ionization line opacities atomic data errors Vinay Kashyap, SAOHMI/AIA Science Teams Meeting, Monterey, Feb 2006

coronal building blocks – moss DEM Fletcher & de Pontieu 1999; Lin et al – Sun as a star; stars as the Sun – the Capella spike at logT=6.8 Vinay Kashyap, SAOHMI/AIA Science Teams Meeting, Monterey, Feb 2006

DEM challenge: lessons learned MCMC_DEM in PINTofALE – incorrect by ~3x – always check for stability of the solution – watch out for artefacts next to sharp edges – data can be too good; proportionately more difficult to get out of local minima Vinay Kashyap, SAOHMI/AIA Science Teams Meeting, Monterey, Feb 2006