Anish M. Amarsi

Biography

I am a researcher at Uppsala University (since 2021; docent since 2023). Before that, I was a postdoc here (2019 -- 2021), and before that I was a postdoc at MPIA in Germany (2016 -- 2019). Earlier, I was a PhD student at ANU in Australia supervised by Martin Asplund and Remo Collet (2013 -- 2016), and a BA/MSci student at the University of Cambridge in the UK (2009 -- 2013).

Research

The central focus of my research is on making accurate models of the light that emerges from stars like the Sun. By comparing these models against real observations of stars, it is possible to infer essential properties of the stars --- in particular, their chemical compositions. To a good approximation, the present-day chemical compositions of Sun-like stars reflect the compositions of the gas from which the stars formed at their respective times of birth. Thus, by studying stars of different ages and different orbits in this manner, it is also possible to learn about the history and evolution of our Galaxy and the cosmos.

Keywords include:

• Atomic processes
• 3D non-LTE radiative transfer
• Spectroscopic models of late-type stars
• The solar chemical composition
• Stellar parameters and chemical compositions
• Galactic chemical evolution

Funding

My funding comes from the Swedish Research Council (Starting Grant, Accurate compositions of Sun-like stars, VR2020-03940), and the Royal Swedish Academy of Sciences (Crafoord Grant, The nature of neutron-star mergers via high-accuracy stellar abundances, CR2024-0015).

Teaching and supervision

I was previously responsible for the Bachelor's course Astrophysics I, and the Master's course The Physics of Stars. Currently I am responsible for the Master's course The Physics of Galaxies. I (co-)supervise(d) several PhD students: Irene Amateis, Sema Caliskan (lead supervisor), Cis Lagae (thesis), Jack Mallinson (thesis), and Xudong Gao (thesis). I also supervise one or two Bachelor's or Master's projects each year. If you are interested in developing astrophysical methods and codes, or in running and analysing computer simulations, or in using these models to analyse and interpret observed stellar spectra, then feel free to reach out!

Gallery

Photos of a few conferences and visits from over the years.

Publications

List of publications in a PDF document

List of publications on NASA ADS

Google scholar profile

ORCID profile

Link to PhD thesis

Data

1D non-LTE departure coefficients (different "versions" for different elements and models)

3D non-LTE line profiles and abundance corrections for Ca2 in metal-poor stars (Lagae+ 2025)

1D non-LTE abundance corrections for Cu1 (Caliskan+ 2025)

3D non-LTE abundance corrections for Mg1 (Matsuno+ 2024)

3D non-LTE abundance corrections for Fe1 and Fe2 (Amarsi+ 2022)

3D non-LTE abundance corrections for C1, O1, Fe2 (Amarsi+ 2019)

1D non-LTE abundance corrections for K1 (Reggiani+ 2019)

3D non-LTE line profiles for H-alpha, H-beta, and H-gamma (Amarsi+ 2018)

1D non-LTE abundance corrections for Si1 (Amarsi & Asplund 2017)

1D/Mean-3D non-LTE abundance corrections for Fe1 and Fe2 (Amarsi+ 2016)

3D non-LTE equivalent widths and abundance corrections for O1 (Amarsi+ 2015,2016)

Links

Homepage of the Atomic Astrophysics group at UU

VR project description

1D non-LTE abundance corrections via INSPECT

WebSME for online spectral synthesis (and 1D non-LTE abundance corrections -- experimental)

PySME for spectral synthesis (can use pre-computed departure coefficients for 1D non-LTE analyses)

Atomic data and codes via Paul Barklem's github page

UU Astronomy/Space Physics seminars

Talk for the IAU G5 seminar series

Talk for the IReNA seminar series