ATOMDB 1.3.1

The Chandra X-Ray Center is pleased to introduce the ATOMDB version 1.3.1 on 3 July 2003. ATOMDB is an atomic database useful for X-ray plasma spectral modeling. Our goal is to incorporate critically evaluated data into ATOMDB. The Emission Line Project is one way we are working to benchmark and improve the data.

This is an interim release with no changes to the underlying atomic database.The only change is that the models now extend to 50 keV. Please see the the release notes for more details.

For interactive line lists and data from ATOMDB please use WebGUIDE.

ATOMDB provides improved spectral modeling capability through additional emission lines, accurate wavelengths for most strong X-ray transitions, and new density-dependent calculations. While many of the improvements are directed toward X-ray grating data analysis, some differences between ATOMDB and other models might be noticeable even at moderate (CCD) resolution.

Only for some of the strongest lines do we include lines from levels above n=5; a table of the physics underlying the ATOMDB shows the highest values used.

The atomic database ATOMDB includes the Astrophysical Plasma Emission Database (APED) and the spectral models output from the Astrophysical Plasma Emission Code (APEC). The APED files contain information such as wavelengths, radiative transition rates, and electron collisional excitation rate coefficients. APEC uses these data to calculate plasma model spectra. The APEC output models in ATOMDB are for optically-thin plasmas in collisional ionization equilibrium. APEC outputs separate continuum and line emissivity files, making it easy to model continuum and line emission separately as well as together.

The ATOMDB is used by Sherpa, GUIDE and ISIS to identify emission lines and to calculate spectra for comparison with observations. All the files in the ATOMDB are in FITS format, and can be easily read using the CIAO's Prism.

WARNING: There are a number of important caveats to this release. Despite the many improvements we have made, in some cases using the mekal or raymond models may be a better choice. Please read the caveats carefully!

If you use these models, please email rsmith@head-cfa.harvard.edu so we can notify you when updates or corrections are made.

Frequently Asked Questions

How complete are the ATOMDB energy models?

How do I use APEC in CIAO?

How do I calculate fluxes from emissivities?

How do I use APED and APEC in IDL?

Last modified: 7 March 2005

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