The present paper describes version 2.0 of the CHIANTI database, including data for a large number of ions not included in the present version of the database, more recent transition probabilities for ions already included in the database, and a full set of data and IDL routines to calculate free-free, free-bound and two-photon continuum radiation.
The present version of the database allows a better reproduction of the optically thin spectrum for wavelengths greater than 50 Å and is able to account for most of the lines observed by the most advanced spectrometers.
In principle, there is no upper limit to the CHIANTI wavelength coverage, but beyond
1100 Å lines from neutral species begin to dominate the spectrum and neutrals are
not presently included in
the CHIANTI database. The database is still incomplete below 50 Å mostly because of
the omission of the hydrogen and helium isoelectronic sequences.
In view of the forthcoming missions such as AXAS (1-140 Å), XMM (5-35 Å) and
ASTRO-E (
Å) it is important to have also a database
covering wavelengths shorter than 50 Å: a new release of the CHIANTI database will
extend the covered spectral range to these wavelengths. It is to be noted that recently
the atomic data for the H-like sequence have been assessed and critically evaluated by
the Utrecht group (Kaastra 1998)
as part of a major update of the MEKAL code; this careful and extensive
work will be a starting point for the future extension of the CHIANTI
database. Also, the
Mewe & Kaastra (1994)
improvements to the continuum model
will be included in the next release of the CHIANTI database.
The CHIANTI database and the corresponding set of IDL programs are freely available from the following web sites:
http://wwwsolar.nrl.navy.mil/chianti.html
http://www.arcetri.astro.it/science/chianti/chianti.html
http://www.damtp.cam.ac.uk/user/e2e/chianti/chianti.html
A README file explains the procedures for copying the Unix compressed tar files to a user's computer. The IDL routines assume a Unix file structure but they could be adapted to other operating systems.
AcknowledgementsThe CHIANTI consortium also includes B.J.I. Bromage and G. Del Zanna (University of Central Lancashire) and C.D. Pike (Rutherford Appleton Labortaory) who have been involved in the software development and applications to the analysis of CDS data. The financial support of the Italian Space Agency (ASI contract 1995-RS 120) and the Italian Ministry of University and Technological Development (MURST contract 40% 1996) are aknowledged by EL and ML. HEM and PRY acknowledge the financial support of PPARC. A NATO grant has enabled the CHIANTI consortium to meet and for individuals to visit other institutes. We are grateful to Dr. R. Mewe for useful comments on the original manuscript.
Copyright The European Southern Observatory (ESO)