Atomic data for Fe-peak elements
Lead Research Organisation:
Queen's University Belfast
Department Name: Sch of Mathematics and Physics
Abstract
There is an overwhelming need for high quality atomic data for interpreting astronomical spectra. In a new era of high resolution astrophysical spectroscopy, the interpretation of observations is dependent on an ability to understand and model these spectra. While some of the atomic data can be obtained experimentally, they are frequently of insufficient accuracy or limited to a small number of transitions. Computational approaches are the only means by which data of the required quality and quantity can be obtained. In this programme it is our aim to provide high quality, reliable atomic data related to key areas of application. Our work focuses on the provision of atomic data pertaining to the astrophysically important Fe-peak elements, data which is imperative for the interpretation and understanding of observational data from key ongoing, or planned, space or ground based missions.
Publications
Cassidy C
(2012)
Ni II: A comprehensive atomic data study with emphasis on astrophysical applications
in Journal of Physics: Conference Series
Cassidy C
(2010)
Electron-impact excitation of Ni II Collision strengths and effective collision strengths for low-lying fine-structure forbidden transitions
in Astronomy and Astrophysics
Cassidy C
(2011)
ELECTRON-IMPACT EXCITATION OF Ni II: EFFECTIVE COLLISION STRENGTHS FOR OPTICALLY ALLOWED FINE-STRUCTURE TRANSITIONS
in The Astrophysical Journal
Cassidy C. M.
(2016)
VizieR Online Data Catalog: Transitions between Ni II bound states (Cassidy+, 2016)
in VizieR Online Data Catalog
Conroy A
(2018)
Towards the Provision of Accurate Atomic Data for Neutral Iron
in Galaxies
Delahaye F.
(2018)
A Quantitative Comparison of Opacities Calculated Using the Distorted-Wave and R-Matrix Methods
in Workshop on Astrophysical Opacities
Fernández-Menchero L
(2018)
Estimating the Level of Uncertainty in Electron-Impact Excitation and Photoionisation Rates of Low-Ionised Stages of Ni Ions
in Galaxies
Fernández-Menchero L
(2019)
Spectroscopic diagnostics of low-ionized iron-peak elements. Electron-impact excitation of Ni3+ and photoionization of Ni2+
in Monthly Notices of the Royal Astronomical Society
Grieve M
(2012)
Electron-impact excitation of Sc ii: collision strengths and effective collision strengths for fine-structure transitions Electron-impact excitation of Sc ii
in Monthly Notices of the Royal Astronomical Society
Grieve M
(2013)
ELECTRON-IMPACT EXCITATION COLLISION STRENGTHS AND THEORETICAL LINE INTENSITIES FOR TRANSITIONS IN S III
in The Astrophysical Journal
| Description | A complete simulation of Fe II atomic data has been completed. This includes radiative data and collisional data to include electron impact excitation and photoionization of a selection of astrophysically relevant Fe-peak ions. This data will be hugely beneficial to the astrophysics and plasma physics communities and will be used to model a variety of spectra. Errors have been estimated for all the data and convergence analysed. |
| Exploitation Route | These data will be placed in a variety of databanks around the world (CHIANTI, CLOUDY, XSTAR, STOUT, ADAS) for use by the astrophysics and plasma physics communities. |
| Sectors | Aerospace, Defence and Marine,Energy |
| Title | ADAS |
| Description | OPEN-ADAS is a system to search and disseminate key data from the Atomic Data and Analysis Structure (ADAS). ADAS is a computer program managed by the University of Strathclyde and made up of a consortium of over twenty members. The OPEN-ADAS system enables non-members, with an interest in fusion and astrophysics, to download and use ADAS data. |
| Type Of Material | Database/Collection of data |
| Provided To Others? | No |
| Impact | All of the atomic data produced by the QUB team relating to fusion research are place in this database for use by modellers in astrophysics and fusion research. |
| URL | http://open.adas.ac.uk/ |
| Title | ADAS |
| Description | OPEN-ADAS is a system to search and disseminate key data from the Atomic Data and Analysis Structure (ADAS). ADAS is a computer program managed by the University of Strathclyde and made up of a consortium of over twenty members. The OPEN-ADAS system enables non-members, with an interest in fusion and astrophysics, to download and use ADAS data. |
| Type Of Material | Database/Collection of data |
| Provided To Others? | No |
| Impact | All of the atomic data produced by the QUB team relating to fusion research are place in this database for use by modellers in astrophysics and fusion research. |
| URL | http://open.adas.ac.uk/ |
| Title | CHIANTI |
| Description | CHIANTI consists of a critically evaluated set of up-to-date atomic data, together with user-friendly programs written in Interactive Data Language (IDL) and Python to calculate the spectra from astrophysical plasmas. |
| Type Of Material | Database/Collection of data |
| Provided To Others? | No |
| Impact | All of the atomic data created at QUB are stored in the CHIANTI database for use by the astrophysics and plasma physics communities. |
| URL | http://www.chiantidatabase.org/ |
| Title | CLOUDY/STOUT |
| Description | Cloudy is a spectral synthesis code designed to simulate conditions in interstellar matter under a broad range of conditions. It is provided for general use under an open source License. |
| Type Of Material | Database/Collection of data |
| Provided To Others? | No |
| Impact | The modelling code CLOUDY, developed by Ferland (University of Kentucky), is employed by astrophysicists worldwide to analyse the spectra of a myriad of astronomical sources, ranging from gaseous nebulae to high- redshift quasars. An essential component of any plasma modelling code is highly accurate atomic data for a range of processes, including radiative rates and electron-impact excitation cross sections. For most of these atomic processes, experimental results are not widely available, and theoretical data must be employed. |
| URL | http://www.nublado.org/ |
| Description | ADAS-EU: |
| Organisation | University of Strathclyde |
| Department | Department of Civil and Environmental Engineering |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Dr Ramsbottom is an active members of the ADAS-EU consortium. ADAS-EU is a support activity for implementation of atomic data in plasma diagnostics and modelling at fusion laboratories throughout Europe, for management of databases of relevant fundamental and applied data and for promotion of key fundamental atomic data calculation and measurement. It will enable improved effectiveness of analysis of existing fusion experiments and prepare for ITER. Members of this group hail from Universities worldwide, from the USA, UK, Europe and Japan. |
| Collaborator Contribution | As above |
| Impact | Publications |
| Start Year | 2010 |
| Description | Atomic Physics for Astrophysics |
| Organisation | Kentucky State University |
| Department | Department of Physics and Astronomy |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Dr Ramsbottom has established a major collaboration with Prof G Ferland of Kentucky University relating to the use of Fe II emission lines as a chronometer for high red-shift quasars. The high red-shift quasars are the most distant objects we can observe spectroscopically and the emission we observe was produced when the Universe had an age of roughly 1 Gyr. This youth limits and simplifies the amount of nucleosynthesis that can have occurred. This innovative project aims to fully simulate the physical conditions within Fe II emitting gas and predict the resulting spectrum. The numerical simulations will be used to deduce iron abundances from Fe II emission in high-redshift quasars. This, in conjunction with predictions of stellar evolution and galactic nucleosynthesis, will result in a chronometer measuring the redshift when the universe passed through an age of 1 Gyr, thus constraining cosmological parameters and the onset of star formation. For this work to be successful, it is imperative that the Fe II scattering model be as large and as complete as possible. Two PhD students have already been supported by the Prof. James Caldwell travel scholarship (QUB) to visit Auburn University, USA and The University of Kentucky, USA to strengthen and initiate new collaborations with international members of the astrophysical community. The group at QUB is responsible for the atomic data generation for this exciting project. |
| Collaborator Contribution | The contribution made to the project from Kentucky state University is their expertise in the development, use and experience in the CLOUDY modelling code. Our collaborator Prof G. Ferland is the founder of this internationally used modelling code. |
| Impact | Joint publications Prof Ferland spent 10 months at QUB funded by a Leverhulme visiting program |
| Start Year | 2008 |
| Description | The International Iron Project: |
| Organisation | University of Strathclyde |
| Department | Department of Physics |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Dr Ramsbottom is a member of the International Iron Project and indeed has been a full and active contributor since 2002. This group of collaborators meet at least once per year to discuss issues relating to the production of accurate atomic data for use in plasma and astrophysical applications. Members hail from Universites in the USA (Auburn, Ohio, Rollins Florida, Venezuela)), the UK (QUB, Strathclyde, UCL, Daresbury) and Europe (Munchen Germany, Nice, Observatoire de Paris France). The next meeting is to be held in Paris France in April 2016. |
| Collaborator Contribution | This group of collaborators meet at least once per year to discuss issues relating to the production of accurate atomic data for use in plasma and astrophysical applications. |
| Impact | Joint publications Regular meetings |