Calculation of Fe II Atomic Data Required For the Modeling of HST Observations

The atomic data we calculate will be of immediate benefit to our STIS observations of RR Tel (GO-S09S), as they are urgently required to reliably model the Fe II emission line spectrum of this object. However, our collisional rate calculations will also be of benefit to the analysis of all HST observations which contain Fe II features. These will include e.g. stellar spectra, circumstellar observations (such as planetary nebulae and supernovae), as well as HST results for extragalactic sources, including active galaxies. Hence our work will be applicable to a very large portion of the current HST Archive, as well as future observations. During the first year of our program, we will include Fe II states in our PRMAT calculations arising from the additional 3d 4d configuration, allowing us to derive accurate atomic data for transitions among other levels, widely detected in UV spectra from HST. During this time we will also undertake modifications to the PRMAT code to allow fine-structure rates to be generated from the results in LS-coupling. In the second year, we will extend our PRMAT calculations to include states arising from other configurations, permitting the emission lines from these levels in HST spectra to be reliably modelled. Our atomic data will be made available to the astronomical community in two ways. Firstly, the atomic data will be placed on our websites, and also on other relevant websites, such as Dima Verner's Atomic Data for Astrophysics at www.pa.uky.edu/ verner/atom.html where they may be freely accessed by anyone who wishes to use the results in their modelling work. The availability of the atomic data will be advertised via the usual channels, namely presentations at conferences and refereed papers, with all conference/refereed papers also placed on abstract servers (such as astro-ph). Secondly, one of us (Ferland) will include the atomic data in his CLOUDY code www.pa.uky.edu/gary/cloudy which is used extensively by the astronomical community. This is illustrated by the fact that currently over 100 papers are published each year which employ CLOUDY. Inclusion of our Fe II atomic data in CLOUDY will ensure that our results will be employed very quickly by the community to analyse their HST observations of a wide variety of astronomical sources. This proposal represents a new dimension to our numerical quantitative spectroscopy program at the University of Kentucky in Lexington. Ferland is the developer of the widely-used spectral simulation code CLOUDY. These simulations rest on a foundation of basic atomic data. The simulations and the atomic data are a two-way street-the simulations make new demands on the atomic data, and advances in atomic physics point to new avenues of research in astrophysics. Our work in Lexington has been strongly supported by our Center for Computational Sciences (CCS). CCS has a HP Superdome SDX 54-way processor, which is among the twenty most powerful computers in academic institutions in the USA. Access to this machine is provided to all University of Kentucky researchers free of charge. We plan to employ Dr. Cathy Ramsbottom at Lexington for a 2-year period, to port the PRMAT code from Queen's University Belfast (QUB) to Lexington, and use the SDX to perform the Fe II calculations detailed in the Scientific Justification. Dr. Ramsbottom has extensive experience in PRMAT calculations for Fe II and is part of the core consortium at QUB which has developed the PRMAT code. A period of foreign activity, here in the USA, would be part of the normal professional development for Dr. Ramsbottom, leading to an eventual permanent job in the United Kingdom. Her working in the USA will create additional infrastructure that will have impact beyond the specific application we propose, since Dr. Ramsbottom will train others in the use of the PRMAT code.