Atomic Physics Measurements in Support of X-ray Astronomy

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Andrea Montgomery
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1 Atomic Physics Measurements in Support of X-ray Astronomy Your LDRD Representative Graphic Here (Fit in this rectangle, no caption) Oct 27, 2010 Gatlinburg P. Beiersdorfer G. Brown LLNL M. Frankel LLNL* J. R. Crespo MPI Heidelberg P. Desai UC Berkeley M. F. Gu UC Berkeley J. G. Jernigan UC Berkeley J. K. Lepson UC Berkeley M. Obst UC Berkeley R. Kelley Goddard Space Flight Center C. Kilbourne Goddard Space Flight Center D. Koutroumpa Goddard Space Flight Center M. Leutenegger Goddard Space Flight Center F. S. Porter Goddard Space Flight Center S. Kahn Stanford University M. Bitter Princeton Plasma Physics Lab M. Reinke MIT *now Imperial College

Lepson UC Berkeley M. Obst UC Berkeley R. Kelley Goddard Space Flight Center C. Kilbourne Goddard Space Flight Center D. Koutroumpa Goddard Space Flight Center M.

2 Outline

3 High-resolution astrophysical observations illustrate the need for laboratory astrophysics Spectral data bases have been incomplete and cannot identify all lines

4 Evolution of argon EUV emission with beam energy

5 Controlled measurements provide comprehensive spectral catalogues of the lines in the EUV

6 The laboratory data allow us to make new identifications of L-shell lines in stellar coronae

7 Even the Fe L-shell emission spectra still need work

8 Accurate measurements are needed to calibrate outflow velocities near active galactic nuclei

9 Accurate measurements are needed to calibrate outflow velocities near active galactic nuclei

10 The iron M-shell region represents an even bigger problem Holczer et al., APJ 632, 788 (2005)

11 The calculations do not agree The lines cannot be measured in emission because the upper level evaporates by Auger decay

12 Advanced light sources coupled with an EBIT can now address these issues

15 Schematic of the Heidelberg EBIT interacting with a photon beam Photon beam: photons/s ions/cm 2 1 count/s

16 Measurements of the photoionization cross sections of Fe XV relies on ion extraction and charge analysis Fe 14+ monochromator Wien filter position sensitive detector X-ray detector Fe 15+ B E extracted ions collector electrostatic deflector photon beam: photons/s trap gun

position sensitive detector X-ray detector Fe 15+ B E extracted ions

17 Results of Fe XVI photoionization measurements on the BESSY light source 2.0 Fe XVII [a.u.] Overview photoionization spectrum Photon energy [ev] 0.6 Details of resonances Fe XVII (a.u.) Fe XVII Fe 16+ (a.u.) Photon energy (ev) Photon energy (ev) Photon energy (ev)

6 Details of resonances 0.7 0.7 Fe XVII (a.u.) 0.5 0.4 0.3 Fe XVII 0.6 0.5 0.4 0.6 Fe 16+ (a.u.) 0.5 0.4 0.3 0.

18 The comparison of Fe XV results with theory favors the recent FAC/MBPT calculations Red curve: HULLAC Black curve: FAC/MBPT Magenta: EBIT/BESSY data Wavelength (Å)

21 Interfacing the HD EBIT with an advanced light source can be done rather rapidly The next experiments are planned for the week of February 9, 2011 on the Linear Coherent Light Source (LCLS) at SLAC

22 Fe XVI lines produced by dielectronic recombination (DR) 3d > 2p DR satellite lines No 3s > 2p DR satellite lines

23 Fe XVI DR satellites are important for Chandra HETGS observations

24 The DR satellite lines are needed for best fit

25 The DR satellite line intensity depends on temperature and can be used to get the Fe XVII emission temperature

27 Ionization fractions are also being investigated theoretically and experimentally Experimental rate coefficients for dielectronic recombination for forming Fe 15+ from Fe 16+ were recently reported [Schmidt et al., JPhysCS 163, (2009)] (+ posters by Savin et al.)

28 Storage ring measurements provide new rates for both ionization and recombination

29 Time-dependent measurements of the Fe XVII spectrum allow us to measure radiative lifetimes

30 Time-dependent measurements of the Fe XVII spectrum allow us to measure radiative lifetimes

31 The measurement distinguishes among a spread of theoretical results for the Fe XVII M2 radiative rate

32 Astrophysical Fe XVII spectra have been puzzling

33 Astrophysical Fe XVII spectra have been puzzling

34 Astrophysical Fe XVII spectra have been puzzling

35 Numerous theoretical papers have tried to address these issues since the first measurements in the 70!s

36 In 2006 the Livermore group went beyond line ratios and measured excitation cross sections

37 The Livermore cross section measurements raised the bar for theory

38 A new calculation quickly changed the R-matrix results to values that agree better with measurement A subsequent paper GX Chen confirmed his 2007 calculations and suggest the measured value to be in error [GX Chen, PRA 77, , (2008)] In a companion paper GX Chen finds the theoretical values used for normalization of the measurement to be wrong by 24% - if so, this would bring experiment into agreement with his own numbers [GX Chen, PRA 77, , (2008)] Most recently, GX Chen et al. find that the previous calculations of the X-ray line polarization to be off by 30% or more [GX Chen et al., PRA 79, (2009)]

39 The Fe XVII saga continues: What if GX Chen!s 2007 & 2008 calculations were correct? Measured ratio = 2.98

40 MF Gu!s paper hints at what aspect of theory needs to be improved

41 The Fe XVII saga continues Last month Zhang, Fontes & Ballance showed the result of GX Chen et al. to be wrong and reaffirmed the 1990 results of Zhang et al. concerning X-ray line polarization [Zhang et al., PRA 82, , (2010)]

42 EUV lines also provide crucial electron density diagnostics

43 EUV lines also provide crucial electron density diagnostics

44 EUV lines also provide crucial electron density diagnostics

45 Laboratory calibration of density-sensitive line ratios Tokamak Laboratory data spans multiple decades of density

46 Laboratory calibration of density-sensitive line ratios: Comparison with Capella LETGS observation

47 Charge exchange between heavy solar ions and neutrals in a comet!s coma

48 Some recent articles on charge exchange Cross sections C q+, O q+, Ne q+ ions colliding with H 2 O, CO, and CO 2 [Mawhorter et al., PRA 75, (2007)] C q+, N q+, O q+ ions colliding with CH 4 [Djuric et al., ApJ 679, 1661 (2008)] Fe q+ ions colliding with CO and CO 2 [Simcic et al., PRA 81, (2010)] Fe q+ ions colliding with H 2 O [Simcic et al., ApJ 722, 485 (2010)] X-ray spectra Fe q+ ions colliding with N 2 [Beiersdorfer et al., ApJ 672, 726 (2008)] S 10+, S 11+, S 12+, S 13+ ions colliding with SF 6 [Frankel et al., ApJ 702, 171 (2009)] Ne 10+ ions colliding with He, Ne, Ar [Ali et al., ApJ 716, L95 (2010)] Ar 17+, Ar 18+, P 14+, P 15+ ions colliding with H 2 [Leutenegger et al., PRL 105, (2010)] + measurements (ORNL) and calculations - posters + next talk by Phil Stancil

49 Differences between collisional and charge exchanged induced spectra: L-shell sulfur emission Frankel et al., ApJ 702, 171 (2009)

50 Summary Koutroumpa et al., in preparation

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