July 11 X-Ray Gratings Workshop Capella Grating Data and the Emission Line Project - An Update Priya Desai (CfA) Nancy Brickhouse Jeremy Drake Dave Huenenmoerder Randall Smith Andrea Dupree Vinay Kashyap

July 11 X-Ray Gratings Workshop Outline What is the Emission Line Project (ELP)? Some results and existing problems – Using Capella grating data Future Plans

July 11 X-Ray Gratings Workshop What is the Emission Line Project? - Collaborative effort organized by CXC -To use the calibration data to identify potential atomic data problems that can be addressed theoretically or in the laboratory-mostly Capella - Primary Goals: - to improve the plasma spectral models used to analyze and fit X-ray spectra. - catalog of observed spectral lines

July 11 X-Ray Gratings Workshop Publications related to the ELP Chen, G.X., Smith, R.K., Brichouse, N.S.,Wargelin, B.J., Phys Rev A, 2006, 74, Gu, M.F., Gupta, R., Peterson, J.R., Sako, M., 2006, ApJ, 649, 979 Keenan, F.P., Drake, J.J., Chung, S., Brickhouse, N. S., Aggarwal, K.M., 2006, ApJ, 645, 597 Ishibashi, K., Dewey, D.,Huenenmorder, D., Testa, P., ApJ, 644, L1171 Desai, P., et al,2005, ApJ, 625, L59 Ness, J.U., Brickhouse, N.S., Drake, J.J., Huenenmorder, D., 2003, ApJ, 598, 1277 Campbell,S.M., Brickhouse, N.S.,2001, AAS, C Ayres, T. R., 2001,ApJ, 549, 554A

July 11 X-Ray Gratings Workshop Some Results Fe XVIII and Fe XIX EUV to X-ray discrepancies Line Identifications Ne IX G -ratios in Capella

July 11 X-Ray Gratings Workshop Capella :X-rays LETG 355 ks HETG/HEG 300 ks HETG/MEG 300 ks -- Fe XVIII(resonance) Fe XVIII

Desai et al For the strongest lines, the codes agree: discrepancies are 30% for Fe XVIII and a factor of 2 for Fe XIX. X-ray Fe XVIII Fe XIX EUV FUV All X-ray/EUV line ratios are larger than predicted (by all codes). Fe XVIII and Fe XIX X ray to EUV discrepancies Why Capella ? Atomic Physics

July 11 X-Ray Gratings Workshop Interstellar Absorption? Partially ionized Hydrogen => more Helium Gu et al N H =1.6e18 N H =7.2e18 N H =1.6e19

July 11 X-Ray Gratings Workshop Interstellar Absorption? N H =1.8e18cm -2 N H =7.2e18 N H =1.6e19

July 11 X-Ray Gratings Workshop Fe XVI line ratios N H =7.2e18 N H =1.6e19 N H =1.8e18 Predicted line ratio (335.1/360.8 )

July 11 X-Ray Gratings Workshop Fe XVI line ratios N H =1.8e18cm -2 N H =7.2e18cm -2 N H =1.6e19cm / / /63.7

July 11 X-Ray Gratings Workshop Blending with FeXIX in the Ne IX triplet region Model Fe XIX lines from HULLAC(1% accuracy)

July 11 X-Ray Gratings Workshop Blending with FeXIX in the Ne IX triplet region With EBIT λ measurements (Brown et al. 2002, 5-10 mÅ)

July 11 X-Ray Gratings Workshop Fe XIX Model Wavelengths Kotochigova et al With this Fe XIX model we can match the positions of all features in the spectrum.

Derived T from Capella in better agreement G-ratio agrees with LLNL EBIT measurements of Wargelin (PhD Thesis 1993) New Ne IX G-ratio calculations (Chen et al. 2006, PRA) Recent Results

July 11 X-Ray Gratings Workshop New Calculated G-ratios Ness et al Ne IX G- ratios don’t predict the correct temperature Chen et al improved calculations bring it more in line with observations

July 11 X-Ray Gratings Workshop Future Plans A lot of work in theory and lab astro Catalog of emission lines Access to Users

Blending with Fe XIX in the Ne IX Spectral Region Model Fe XIX wavelengths from HULLAC (1% accuracy) With EBIT λ measurements (Brown et al. 2002, 5-10 mÅ)

Fe XIX Model Wavelengths from Dirac-Fock-Sturm Method Kotochigova, in progress With this Fe XIX model we can match the positions of all features in the spectrum.

Ne IX “R-ratio” and “G-ratio” Classic He-like diagnostics “R-ratio” = f/i is density-sensitive. “G-ratio” = (f + i)/r is temperature- sensitive. f = forbidden 1s 2 1 S 0 - 1s2s 3 S 1 i = intercombination 1s 2 1 S 0 - 1s2p 3 P 2 1s 2 1 S 0 - 1s2p 3 P 1 r = resonance 1s 2 1 S 0 - 1s2p 1 P 1

July 11 X-Ray Gratings Workshop But there still is a problem! Fe XVI calculations

July 11 X-Ray Gratings Workshop Improved wavelength calculations Provides substantial cleaning up of the Angs Ne IX region

July 11 X-Ray Gratings Workshop

July 11 X-Ray Gratings Workshop

July 11 X-Ray Gratings Workshop

July 11 X-Ray Gratings Workshop