News
January 12th 2025: AtomDB Workshop 2025 Announced
The 2025 AtomDB workweek and workshop will be held August 25th-29th at the Center for Astrophysics in Cambridge, MA. More Details.
January 3rd 2025: AtomDB 3.1.0
The new version of AtomDB has been released and is now available on the download page. Documentation is being prepared and will be shared as soon as possible.
August 8th 2024: ACX2 Updated
The ACX2 model has been improved to run faster and has interface improvements, available at the Github page.
January 5th 2024: Publications
We recently published 2 papers in the Astrophysical Journal:
" New Resonance Scattering Model in AtomDB: Application to Line Suppression in Galaxy Clusters and Elliptical Galaxies" by Priyanka Chakraborty (ADS)
This paper introduces our new resonance scattering model rsapec.This model is compatible with pyXSPEC and offers an alternative to the commonly employed APEC model for fitting X-ray spectra characterized by optically thick lines. An example script to run rsapec is in the AtomDB: Example Script page.
" Investigating the impact of atomic data uncertainties on measured physical parameters of the Perseus galaxy cluster " by Priyanka Chakraborty (ADS)
This paper explores the impact of atomic data uncertainties on measured physical parameters of Perseus galaxy cluster using the atomdb tool variableapec
June 1st 2021: Publications
The AtomDB project has published 2 papers recently:
"Spectral Implications of Atomic Uncertainties in Optically Thin Hot Plasmas" by Keri Heuer (ADS)
This paper describes a method for estimating the sensitivy of line emissivities and line ratios to uncertainties in the fundamental atomic data. The code for this project is on the AtomDB Github GitHub page.
"PyAtomDB: Extending the AtomDB Atomic Database to Model New Plasma Processes and Uncertainties" by Adam Foster and Keri Heuer (ADS)
This paper describes the python interface to AtomDB, pyAtomDB, and the current data file formats in use in AtomDB.
May 26th 2020: AtomDB Workshop and Spectrscopy School Moved Online
Due to the ongoing Covid-19 situation, we have canceled the physical AtomDB Workshop and Workweek. We will instead hold a virtual meeting and spectroscopy school from August 3rd-5th. More details and registration.
January 29th 2020: AtomDB FTP Server Changes, update PyAtomDB
The AtomDB FTP server was moved, which was previously hardcoded into the PyAtomDB routines. We have completed the and released an updated PyAtomDB with the new paths. You can obtain the new version from GitHub ("git pull") or PyPI ("pip install pyatomdb"). Please contact us if you still experience any issues.
January 2020: Online Plotting Tool Released
We have been working on an online tool for plotting AtomDB Spectra. It is available here, and will be updated in the future to display more models and data types. Please provide feedback through the Github page.
November 2019: APEC model revised
Interpolation issues have been discovered in the APEC model. The exact effects of these vary significantly depending on the exact plasma being analyzed and the instrument in use. More details.
November 2019: Kappa and Electron-Electron Bremsstrahlung Model released
Models for non-Maxwellian electrons, and e- - e- collisions, created by Xiaohong Cui, are now available. These include models for including them in XSPEC.
October 2019: ACX2 updated model released
A minor update has been made to the ACX2 model to correct an indexing error in the vvacx model.
October 2019: ACX 1.0.2 model released
We have updated the AtomDB Charge eXchange model to work with HEASOFT 6.24.
Older news
Project Quick Links
There are several different sub-projects under the AtomDB umbrella. These are:
- The AtomDB atomic database (fundamental atomic data)
- The AtomDB equilibrium emissivities (used in XSPEC etc)
- PyAtomDB: an interface for obtaining and interrogating the fundamental data and resulting spectra
- The AtomDB C interfaces (for ionization balance calculation and spectrum generation)
- The AtomDB Charge Exchange Model, ACX
- WebGUIDE, providing online access to the atomic database and emissivities
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.