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News

August 21st 2015: Bug in NEI models for XSPEC 12.9

A bug leading to spurious data the NEI models using any of the AtomDB 3 NEI models in XSPEC 12.9 has been found. See the download section for details and a fix.

August 14th 2015: AtomDB Workshop Schedule Available

See here for details.

June 17th 2015: AtomDB 3.0.2 Released

Minor bugfixes to the AtomDB 3.0.1 database, along with including the Fe I-VII emission. Now available now on the Download page.

March 31st 2015: Libreadapec v0.3 released

The C library for reading the AtomDB emissivity files has been updated. This includes minor bugfixes and significant improvements to the code. Download it here.

March 27th 2015: AtomDB Workshop and Work week 2015 announced

The 2015 AtomDB Workshop and Workweek will be combined with the 2015 Chandra Workshop. It will be held at the Harvard Smithsonian Center for Astrophysics, from 17th-21st August. Details.


Project Quick Links

There are several different sub-projects under the AtomDB umbrella. These are:


What is 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 2.0.0. This is a major update from version 1.3.2, with nearly all atomic data being replaced. Please see the the release notes for more details.

For interactive line lists and data, we provide the AtomDB WebGUIDE and an iPad app.


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 register so we can notify you when updates or corrections are made.

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