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. 2006

– 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