This school aims to provide participants with a solid foundation in the analysis of stellar spectra, with particular emphasis on deriving atmospheric parameters and chemical abundances. The sessions will be structured around iSpec, a comprehensive tool designed for the treatment and interpretation of stellar spectroscopic data. As part of the learning experience, the school will also incorporate and explore recent advances in artificial intelligence.
iSpec facilitates a wide range of spectroscopic tasks, including removing cosmic rays, continuum normalization, resolution degradation, radial velocity correction, identification of telluric lines, and resampling. It also enables the determination of fundamental stellar parameters—such as effective temperature, surface gravity, metallicity, microturbulence, macroturbulence, and rotational velocity—for A, F, G, K, and M-type stars. These parameters can be derived through two complementary approaches: the synthetic spectral fitting technique and the equivalent width method.
The software integrates MARCS and ATLAS model atmospheres. It supports several widely used radiative transfer codes, including SPECTRUM (R. O. Gray), Turbospectrum (Bertrand Plez), SME (Valenti and Piskunov), MOOG (Chris Sneden), and Synthe/WIDTH9 (Kurucz/ATLAS). While iSpec offers a well-suited graphical interface for introductory use and educational purposes, its full potential is realized through its Python-based implementation. This approach is recommended for advanced scientific analyses as it ensures reproducibility and access to an extended set of features and customization options.
During the school, participants will receive a series of introductory lectures on iSpec and engage in hands-on exercises focused on determining the atmospheric parameters of A, F, G, K, and M-type stars. These exercises will use publicly available observational data and pre-computed synthetic spectra. The lecturers include the leading developer of iSpec and experienced stellar spectroscopists who have extensively used this tool (among others) and have trained numerous PhD students and postdoctoral researchers.
The course is open to PhD and master's students and early career scientists. There is no registration fee. All accepted participants will have accommodation and lunches covered during the workshop.
(all lectures and exercises will be in English)
University of Wroclaw, Wroclaw, Poland
Wroclaw Centre for Networking and Supercomputing...
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]]>The Gaia mission is revolutionizing Galactic astrophysics in many ways and, although this is not generally perceived, Gaia is also a formidable spectroscopy machine. However, the best results are obtained by combining Gaia abilities and ground based high resolution spectroscopy. Advantages and limitations must be understood for a better synergy.
The school will discuss the derivation of stellar parameters from spectroscopy and large survey pipelines using classical, high precision and data driven methods. Tutorial sessions are foreseen. The final lecture will be on publication skills. Space for participants to present their research is granted, either as poster or oral presentation.
All sessions will be on-line. Registration is free of charge, but participant number will be limited. Dead-line for registration and abstract submission: Sept. 5th, 2021
The main subjects and the speakers are:
More information at the web site:
https://indico.ict.inaf.it/event/1590/
Registration is now open!
]]>In addition, most radiative transfer codes were updated, as well as the external Equivalent Width measurement tool (ARES), and the Gaia-ESO linelist version 6 was added. Regarding the input file, pre-computed grids were re-computed using the latest radiative transfer code versions, and line selections were re-done for a resolution of 47,000.
Summary:
Access to the article preprint and the ADS record.
]]>The aim of this school is to give participants a thorough introduction into the treatment and analysis of stellar spectra, including deriving the atmospheric parameters and the chemical abundances. The tool which will be used for this purpose is the code iSpec.
iSpec is a tool for the treatment and analysis of stellar spectra. Some of the main functionalities for spectra treatment and library creation that are integrated into iSpec are the following: cosmic rays removal, continuum normalization, resolution degradation, radial velocity determination and correction, telluric lines identification, re-sampling. iSpec is also capable of determining atmospheric parameters (i.e effective temperature, surface gravity, metallicity, micro/macroturbulence, rotation) and individual chemical abundances for FGKM stars by using two different approaches: synthetic spectra fitting technique or equivalent widths method. iSpec integrates MARCS and ATLAS model atmospheres together with the following radial transfer codes: SPECTRUM (R. O. Gray), Turbospectrum (Bertrand Plez), SME (Valenti & Piskunov), MOOG (Chris Sneden), and Synthe/WIDTH9 (Kurucz/Atmos). The user-friendly interface is perfect for learning and testing. However, to take advantage of the full potential, iSpec can be used from Python. This is the recommended way to use iSpec for complex scientific studies, it ensures reproducibility and give access to a wider range of functionalities and options.
The participants of the school "Spectroscopic data analysis with iSpec" will be given introductory lectures to iSpec and some hands-on experience with determination of the atmospheric parameters of A, F, G, K, and M type stars. The exercises will be based on publicly available stellar spectra as well as on pre-computed synthetic spectra.
The course is open to PhD and master students, and early career scientists.
The master and PhD students will be required to provide a short explanation how this school will be beneficial for their future career development, and to provide a recommendation letter written by the supervisor of their master or PhD thesis.
The participants will be required to have installed and tested on their own computers all the software that will be used during the school, i.e. iSpec and python.
The instructions for installing iSpec have been provided on this web site. The organizers will distribute the needed instructions, including several ways of installing iSpec, several weeks before the beginning of the workshop, encouraging everybody to have iSpec installed. They will also provide all help that will be possible remotely.
The registration fee will be no more than 200 euros, a small fee reduction may be granted for a limited number of students that apply for it.
(all lectures and exercises will be in English)
Links: Article, Github, Documentation.
]]>In 2015, Mozilla Research released the first stable version of a new programming language named Rust. Many features make this new language attractive for the scientific community, it is open source and it guarantees memory safety while offering zero-cost abstraction.
We explore the advantages and drawbacks of Rust for astrophysics by re-implementing the fundamental parts of Mercury-T, a Fortran code that simulates the dynamical and tidal evolution of multi-planet systems.
Links: Article, Benchmark codes, Hacker news and Rust subreddit comments.
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