What is the ATOMDB?
ATOMDB is an atomic database useful for X-ray plasma spectral modeling. The current version of ATOMDB is primarly used for modeing collisional plasmas, those where hot electrons colliding with astrophysically abundant elements and ions create X-ray emission. However, ATOMDB is also useful when modeling absorption by elements and ions or even photoionized plasmas, where X-ray photons (often from a simple power-law source) interacting with elements and ions create complex spectra.
Our goal is to incorporate not only all relevant data, generated both from theoretical models and experiment, but also to critically evaluate this data to create recommended models. Each revision of the critically evaluated database is given a version number to aid reference.
The current release is version 1.3.2. This is an interim update to version 1.3.0, with no changes to the underlying atomic database.The only change is that the models now extend to 50 keV, and some internal keywords have been updated. Please see the the release notes for more details.
For interactive line lists and data, we provide the ATOMDB 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.
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 register@atomdb.org with subject "Register" so we can notify you when updates or corrections are made.