I combine high-resolution stellar spectroscopy and cosmological simulations to reconstruct how the Milky Way formed and where the chemical elements originate. I develop scalable, data-driven pipelines that translate spectra into precise and interpretable measurements, including applications beyond astronomy.
Dr Sven Buder is an Australian Research Council DECRA Fellow at the Australian National University. He combines high-resolution stellar spectroscopy and cosmological simulations to reconstruct the formation history of the Milky Way and to trace the origin of the chemical elements. He is principal investigator of the million-star Galactic Archaeology with HERMES Survey (GALAH) and its successor GALAH 2, and develops scalable, data-driven pipelines that translate spectra into precise and interpretable measurements for astronomy and interdisciplinary applications.
The advent of a new generation of instruments and telescopes is enabling us to investigate how galaxies like our Milky Way form and evolve by tracing the chemical and dynamical fingerprints of their stars. By decoding this fossil record imprinted in stars through high-resolution spectroscopy and cosmological simulations, we can reveal how galaxies assemble and enrich themselves with heavy elements. I am undertaking research built around three complementary but tightly interlinked themes, with stellar spectroscopy as their unifying thread. Together they form a coherent vision to connect the physics of stars with the formation of galaxies and the origin of elements, and to apply the same analytical and data-driven tools that power astrophysics to broader scientific and educational frontiers.
How did galaxies like our Milky Way build their discs and sustain star formation across cosmic time? This remains one of the central open questions in galaxy formation. While evidence points to early turbulent star formation, bar-driven evolution, and merger-induced heating, their interplay is still not understood. My research aims to quantify how these processes shaped the Milky Way and its analogues by combining resolved chemodynamical data, extragalactic surveys, and cosmological simulations in a unified framework.
These efforts will deliver observation-driven simulation tests linking merger history, satellite evolution, and disc formation.
Where and how are the elements forged? While most elements are now known to originate in stars or their explosions and mergers, major uncertainties remain in how stellar yields and binary evolution shaped the chemical makeup of the Universe throughout cosmic time. This question links every scale of astrophysics from planets to galaxies, and demands both precision spectroscopy and predictive modelling. My research combines data-driven analysis with theoretical insight to address these gaps, and complements 3D NLTE modelling efforts (Lind & Amarsi 2024). These approaches provide the dual foundations of precision and realism that are needed to map how stars create and recycle the elements that shape planets and galaxies.
By combining Veloce's precision with HRMOS-era reach and linking stellar spectroscopy to the formation of planets and galaxies, this theme is driving future key projects on the origin of the elements.
Where else can the tools we develop for stellar spectroscopy be applied to benefit science and society? Spectroscopy is a universal diagnostic of matter: the same principles that reveal the composition of stars can illuminate processes in galaxies, the interstellar medium, and even Earth's environment. This theme extends spectroscopy across wavelengths and disciplines to connect astrophysics, climate science, and education.
A key step toward bridging Galactic and extragalactic astronomy is translating high-fidelity stellar spectroscopy into integrated-light observations.
With collaborators and a postdoctoral researcher, I will develop a library of stellar-population templates from Milky Way spectra flux-calibrated with
Gaia XP data.
These abundance-variable templates will support analyses of integrated spectra from instruments such as
VLT-MUSE and
VLT-MAVIS, overcoming long-standing limitations in population-synthesis models and uniting stellar and extragalactic spectroscopy.
In a pilot project combining GALAH optical spectroscopy with ASKAP radio observations
(Nguyen, Buder et al. 2025),
I demonstrated that cross-wavelength analysis can map the interstellar medium across density regimes.
Building on this, I will expand collaborations with radio astronomers to link atomic and molecular gas phases in the Milky Way using targeted optical spectroscopy.
This work connects to upcoming large-scale surveys and prepares for the Square Kilometre Array by establishing a unified optical–radio view of the Galactic ecosystem.
Together with environmental scientists and our instrumentation team at the ANU who build a wildfire risk monitoring satellite called
OzFuel,
we have shown that we can infer carbon and nitrogen abundances from leaf reflectance spectra by applying the data-driven stellar analysis framework of
The Cannon.
Extending this to indicators such as chlorophyll and pigment ratios will show how astronomical methods can address environmental and sustainability challenges.
My vision is to establish spectroscopy as a shared quantitative language across astronomy and environmental science, and to build a cross-disciplinary training platform where students apply data-driven analysis across domains and develop end-to-end pipelines, from data collection to calibration, archiving, and reproducible analysis. These efforts will turn spectroscopy from a specialised tool into a collaborative and educational framework for data-driven, cross-disciplinary research.
I have led three major GALAH survey data releases as first author, each serving as a community benchmark dataset with strong citation impact.
| Buder, Kos, Wang et al. (2025) |
GALAH DR4 – Million-star scale and extended element coverage. Survey release · Precision spectroscopy · Synthetic spectrum interpolation with neural networks Delivered the next-generation benchmark dataset at near-million-star scale, expanding the chemical and stellar-parameter landscape for the community. |
| Buder, Sharma, Kos et al. (2021) |
GALAH DR3 – Flagship release and benchmark dataset. Survey release · Chemistry, dynamics, ages Major data release enabling large-scale Galactic archaeology and hundreds of follow-up studies across stellar, planetary, and Galactic science. This paper was the most-cited MNRAS paper in 2021 (by citation count). |
| Buder, Asplund, Duong et al. (2018) |
GALAH DR2 – First extraction of up to 23 elements. Survey release · Data-driven spectrum interpolation Delivered a major step forward in sample size and ultimately established The Cannon as innovative tool for large spectroscopic survey analysis. |
| Buder, Lind, Ness et al. (2019) |
Milky Way disc formation and bimodality. Disc evolution · Ages & multi-element chemistry Linked ages and chemistry to clarify the thin/thick disc bimodality and constrain disc formation pathways. |
| Buder, Lind, Ness et al. (2022) |
Accreted halo structure and merger history. Halo assembly · Selection biases Distinguished accreted and in-situ halo populations to test merger history and quantify observational selection effects. |
| Buder, Mijnarends, & Buck (2024) |
Accreted star identification via simulations. Simulations · Calibration Established simulation-based criteria for identifying accreted stars and calibrating observational selection methods. |
| Buder, Buck, Chen, & Grasha (2025) |
Bridging Galactic and extragalactic metallicity studies. Cross-scale comparison · Gradients Connected Milky Way and extragalactic metallicity-gradient measurements with cosmological simulations and highlighted key observational selection biases. |
| Griffith, Weinberg, Buder et al. (2022) |
Data-driven nucleosynthesis exploration. Nucleosynthesis · Abundance patterns Used data-driven residual analyses to disentangle correlated abundance patterns and constrain nucleosynthetic channels and rare populations. |
| Buck, Rybizki, Buder et al. (2021) |
Simulation–observation framework for chemistry. NIHAO-UHD · Chemical evolution Implemented a chemical-evolution framework in NIHAO-UHD zoom-in simulations, enabling direct comparisons to observed multi-element abundance patterns. |
| Owusu, Buder, Ruiter et al. (2024) |
Disc population diagnostics via sodium. Population separation · Elemental diagnostics Demonstrated sodium's diagnostic power for disentangling overlapping stellar disc populations with same age and alpha-process abundances, improving constraints on disc evolution. |
| Ness, Mendel, Buder et al. (2025) |
Pilot study bridging Galactic and extragalactic spectroscopy. Integrated light · Data-driven inference Demonstrated that data-driven spectroscopy can robustly recover chemical abundances from low-resolution, low-SNR extragalactic spectra. |
| Nguyen, Buder, Soler et al. (2025) |
Optical–radio synergy in ISM mapping. Multi-wavelength · ISM Combined optical (GALAH) and radio (GASKAP) data to map the cold interstellar medium and enable future survey synergy (4MOST, SKA). |
I am always happy to discuss potential collaborations. Please feel free to reach out if you think there may be a connection. Below is a short overview of what I bring to collaborative projects.
Scientific expertise
My research focuses on the physics and interpretation of stellar spectra and how stars encode information about
planets, galaxies, and the origin of the elements. I have worked across a broad range of topics connected to stars,
including stellar activity (relevant for exoplanet studies), stellar evolution, chemically peculiar stars, unresolved
stellar populations, and the chemical and dynamical history of galaxies. Through surveys such as GALAH and work
connecting resolved and unresolved spectroscopy, my research spans both Galactic archaeology and
extragalactic archaeology. I am particularly interested in projects that connect stellar physics,
galaxy evolution, and interdisciplinary applications where spectroscopy can reveal new physical insight.
Skills and contributions
My research is embedded in large, team-based spectroscopic surveys and instrument collaborations that map the chemical and dynamical structure of the Milky Way and other galaxies. I enjoy building bridges between surveys, facilities, and communities, and I contribute both scientific leadership and analysis infrastructure across these projects.
A snapshot of my co-author network across institutions worldwide (as of March 2026).
I am currently primary supervisor of 2 PhD students and co-supervisor of 4 PhD students. Since 2020, I have supervised 23 research students across undergraduate, Honours, and PhD levels.
My group is part of a larger RSAA community with a joint weekly meeting called GASP (Galactic Archaeology and Stellar Populations). GASP brings together multiple group leaders and their teams, including faculty members Melissa Ness and Luca Casagrande, and emeritus professors Ken Freeman and Gary Da Costa, as well as their postdoctoral researchers, PhD students, and selected undergraduate researchers. This structure provides students with broad feedback, collaboration opportunities, and exposure to diverse methods across Galactic and stellar astrophysics.
“Working with Sven through the verification of GALAH DR4 abundances was one of the highlights of my PhD.
He played an integral part in my AAT globular cluster observing proposal, which laid the foundation for my Hubble Fellowship.”
— Dr Madeleine McKenzie, who kindly suggested adding this anecdote.
Jump to:
I supervise student projects for ANU students at multiple levels (ASTR3005, Honours, and PhD) that combine scientific questions, real data, and reproducible software. Projects can be astronomy-focused or method-focused. Please reach out if you are interested in stars, the Milky Way, and spectroscopy as a transferable skill.
I place strong emphasis on accessibility and initiative. I make time for my students and encourage them to ask questions early and often. Scientific progress rarely happens in isolation, and I am always happy to discuss ideas, results, or difficulties—especially when something interesting emerges.
At the same time, I expect students to take ownership of their projects. Successful research requires curiosity, persistence, and proactive communication. I encourage students to contact me as soon as they obtain new results, identify unexpected behaviour, or refine a question. Regular interaction and momentum are key ingredients of productive projects.
I pay particular attention to clarity of presentation and reproducibility. High-quality figures, clear scientific storytelling, and transparent, version-controlled code are central components of my supervision. Students work with Git and GitHub from early on, and projects are structured to be fully reproducible. I provide a dedicated project template that includes minimal code examples, a structured report format, and an annotated MNRAS manuscript template: template_student_projects (GitHub) . Clear expectations and constructive feedback are an integral part of my supervision, and projects are designed to be ambitious but achievable.
Projects are typically designed to lead to a publication where appropriate. For PhD students, the programme is structured around multiple publishable research outputs. For Honours students, publication is possible but depends on scope and project development.
Domestic PhD students admitted to ANU typically receive full funding through competitive scholarships. International applicants can find detailed information about entry requirements and funding options at:
I contribute to the following ANU courses:
ANU ASTR2013 field trip to Murriyang (The Dish) and the Anglo-Australian Telescope.
My teaching practice is grounded in evidence-based, research-aligned pedagogy that fosters critical thinking, clear reasoning, and hands-on engagement with scientific data. I aim to create inclusive learning environments in which students develop the analytical, computational, and collaborative skills required for modern astrophysics and for data-driven careers beyond academia.
My approach combines structured and visual explanation with interactive dialogue. I use guided questioning, inspired by the Socratic method, to help students express concepts in their own words, recognise assumptions, and compare approaches. I openly discuss how scientific understanding develops through testing, revision, and learning from mistakes, including my own, to normalise iteration and build intellectual independence.
A second core principle is preparing students for diverse career paths. My secondment as a Research Software Engineer in climate modelling strengthened my understanding of the skills valued outside academia—collaborative coding, version control, reproducibility, and communication across disciplines. These elements now form an integral part of my course design.
Beyond formal teaching, mentoring students is an important part of my role as a researcher and educator. I aim to support students in developing their own scientific ideas while building practical research skills, including programming, data analysis, and scientific communication.
At the Research School of Astronomy & Astrophysics I also contribute to the broader support structure for graduate students by serving on Thesis Oversight Committees. In this role I provide independent advice and guidance to PhD students as they develop and carry out their research projects.
I enjoy helping students refine research questions, navigate technical challenges, and gain confidence in their scientific approach. If you would like to discuss your current work or broader career questions in and outside of astronomy, you are welcome to reach out.
I am also committed to fostering an inclusive and supportive research environment and contribute to initiatives that broaden participation in astronomy.
I coordinate a monthly Skillshare at my institute. This format provides an informal but structured space to share practical research skills, professional development strategies, and effective workflows that are often learned implicitly rather than taught explicitly. Topics include refereeing, ADQL/SQL, GitHub workflows, python packaging, proposal writing, and effective collaboration.
The goal is to foster a collaborative and skill-driven research culture, where students and early-career researchers gain confidence in both technical and professional aspects of academia. Materials are added throughout the year.
I enjoy communicating science to broad audiences, from public talks to interviews. My goal is to make science exciting and approachable for everyone.
On 2 October 2024, I spoke with ABC News Australia about the GALAH Data Release 4, mapping almost one million stars across the Milky Way. The segment highlighted how stellar chemistry reveals the formation history of our Galaxy. You can watch it here.
I regularly give public talks and outreach presentations across Australia, including:
These talks focus on: