Front Cover
Organized by
Laboratory for High Energy Astrophysics
NASA Goddard Space Flight Center

Scientific Organizing Committee
Manuel Bautista (NASA/GSFC), co-chair
Timothy Kallman (NASA/GSFC), co-chair
Peter Beiersdorfer (LLNL)
Nancy Brickhouse (CfA)
Duane Liedahl (LLNL)
Richard Mushotzky (NASA/GSFC)
Anil Pradhan (Ohio State Univ.)
Nicholas White (NASA/GSFC)

Local Organizing Committee
Manuel Bautista (NASA/GSFC)
Timothy Kallman (NASA/GSFC)

Atomic Data Needs
for X-ray Astronomy:

M. A. Bautista,
T. R. Kallman,
A. K. Pradhan

This publication contains written versions of most of the invited talks presented at the workshop on "Atomic Data Needs for X-ray Astronomy", which was held at NASA's Goddard Space Flight Center on December 16-17, 1999.

The idea of hosting such a workshop emerged from an imminent need to update and complete current atomic datasets in anticipation of a new era of high quality X-ray spectra starting with the launching of Chandra and XMM-Newton observatories. At first, our vision of the workshop was of a short and limited attendance event, given the specialization of the topic. But it was soon realized, from the response to the first workshop announcement, that the topic was of much interest to researchers working in X-ray spectra (physicists and astronomers). As a result, the workshop grew to approximately 120 participants from several countries.

The kind of atomic data that interests us are those parameters needed for analysis and modeling of spectra shortward of ~ 100 Å and relevant to ionic species of astronomical interest. The physical mechanisms of interest in the formation of spectra include photoionization, collisional ionization, recombination (radiative and dielectronic), collisional excitation (by electrons and protons), and radiative deexcitation. Unique to X-ray spectroscopy are the ionization and excitation processes from inner-closed shells, in addition to the challenges in interpreting the medium resolution (epsilon/deltaepsilon ~ 0.05 - 0.1) data obtained by current X-ray astronomy experiments. Line wavelengths are of interest too, particularly owing to the high resolution spectra from the new experiments.

The workshop was divided into five major areas: Observational Spectroscopy, Theoretical Calculations of Atomic Data, Laboratory Measurements of Atomic Paramenters, Spectra Modeling, and Atomic Databases.

One comforting finding from the workshop is that the enthusiasm felt by X-ray astronomers about the new observational missions seems to be shared by theoretical and experimental physicists. Talks were presented about several exciting new projects and experimental and theoretical techniques devoted to X-ray spectroscopy. Simultaneously, several new tools for spectral analysis and modeling have recently been developed, together with improved atomic databases.

These proceeding are expected to be of interests to producers and users of atomic data. Moreover, the contributions presented here have been written in a way that can be used by a general audience of scientists and graduate students in X-ray astronomy, modelling, and in computational and experimental atomic physics.


I. Observational Spectroscopy

    Spectroscopy and X-Ray Astronomy
    Stephen S. Holt   1

    Initial Results from the Chandra High Energy Transmission Grating Spectrometer
    C.R. Canizares, D.S. Davis, D. Dewey, K.A. Flanagan, J. Houck, D.P. Huenemoerder, H.L. Marshall, M.L. Schattenburg, N.S. Schulz, M. Wise   5

    First Results of the Chandra-LETGS
    P. Predehl, B. Aschenbach H. Bräuninger, W. Burkert, V. Burwitz, G. Hartner, J. Trümper   11

    Chandra and the Emission Line Project
    N. S. Brickhouse and J. J. Drake   19

II. Theoretical Atomic Calculations

    Theoretical Calculations of Atomic Data for Spectroscopy
    M.A. Bautista  25

    Distorted Wave Calculations And Applications
    A.K. Bhatia   41

    The RmaX Network: R-matrix Calculations for X-ray Atomic Processes
    K.A. Berrington   63

    The Iron Project
    A.K. Pradhan   67

    Photoionization and Recombination
    S.N. Nahar   75

    K-Shell Photoionization of Fe
    B.M. McLaughlin, D. Donnelly, K.L. Bell, M.P. Scott, and F.P. Keenan   85

    The R-matrix with Pseudostates Method
    T.W. Gorczyca, N.R. Badnell, D.C. Griffin, D.M. Mitnik, and M.S. Pindzola   97

III. Experimental Atomic Data

    Laboratory Data for X-Ray Astronomy
    P. Beiersdorfer, G.V. Brown, H. Chen, M.F. Gu, S.M. Kahn, J.K. Lepson, D.W. Savin, S.B. Utter   103

    Time-Resolved Atomic Spectroscopy with Fast-Ion Beams, Heavy-Ion Storage Rings and Ion Traps
    E. Träbert    117

    Tokamak Spectroscopy for X-ray Astronomy
    K.B. Fournier, M. Finkenthal, D. Pacella, M. J. May, V. Soukhanovskii, M. Mattioli, M. Leigheb and J. E. Rice   127

    X-Ray Photoionized Plasmas in the Laboratory
    R.F. Heeter, J.A. Emig, M.E. Foord, R.S. Thoe, P.T. Springer, J. Bailey, M. Cuneo, and C. Deeney   135

    Modeling X-Ray Photoionized Plasmas: Ion Storage Ring Measurements of Low Temperature Dielectronic Recombination Rate Coefficients for L-Shell Iron
    D.W. Savin, N.R. Badnell, T. Bartsch, C. Brandau, M.H. Chen, M. Grieser, G. Gwinner, A. Hoffknecht, S. M. Kahn, J. Linkemann, A.Müller, R. Repnow, A.A. Saghiri, S. Schippers, M. Schmitt, D. Schwalm, A. Wolf, and P.A. Závodszky   143

IV. Modeling Astronomical Spectra

    The Completeness Criterion in Atomic Modeling
    Duane A. Liedahl   151

    Coronal Plasmas Modeling and the MEKAL Code
    J.S. Kaastra and R. Mewe    161

V. Atomic Databases

    Atomic Databases
    C. Mendoza   167

For questions and comments about these proceedings, contact Manuel Bautista at

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