Martin Sahlén
Researcher at Department of Physics and Astronomy; Astronomy and Space Physics
- Telephone:
- +46 18 471 59 70
- E-mail:
- martin.sahlen@physics.uu.se
- Visiting address:
- Ångströmlaboratoriet, Regementsvägen 10
- Postal address:
- Box 516
751 37 UPPSALA
- ORCID:
- 0000-0003-0973-4804
Short presentation
Docent in astronomy with specialization in astrophysics.
RESEARCH
2021-2026: PI, "The Galaxy – Dark Matter Connection with HST, JWST and EUCLID" (8 MSEK)
2022-2024: PI, "Searching for New Physics in the Early Universe" (1 MSEK)
2023-2027: PI, "Astronomical object classification and anomaly detection with complex spectroscopic 4MOST data sets" (4 MSEK)
TEACHING
Responsible for and teacher on the transdisciplinary course "Three Views on Cosmology" (10 hp).
Keywords
- docent
- bayesian inference
- astrophysics
- astronomy
- cosmology
Biography
Hemsida: http://www.astro.uu.se/~msahlen/
Martin Sahlén is docent and researcher in astronomy with specialization in astrophysics at Uppsala University. He studied at the Royal Institute of Technology (KTH) and Cambridge, earned his PhD from the University of Sussex in 2009, and was a postdoctoral fellow at Cambridge, Stockholm and Oxford. He was a Fulbright fellow at Johns Hopkins, and a Natural Sciences fellow at the Swedish Collegium for Advanced Study. He joined Uppsala University in 2016.
Sahlén's research focuses on the large-scale structure of the Universe, and its connection to astrophysics and fundamental physics. In particular, he is investigating the very first generations of galaxies, and late-Universe galaxy distributions. Recent work includes the demonstration of the power of galaxy clusters and cosmic voids as probes of deviations from General Relativity and to measure the mass of neutrinos, the first cosmological parameter estimation based on cosmic voids, and discovery of a powerful new test of modified gravity theories. He is member of the 4-metre Multi-Object Spectroscopic Telescope (4MOST), the BUFFALO survey, the Euclid Consortium, the SKA Observatory, and an external collaborator in the Dark Energy Survey. Sahlén also works on the philosophy of astrophysics and cosmology. His research was highlighted in “The Best Writing on Mathematics 2018”.
Research
Theoretical and observational studies of the large-scale structure of the Universe through clusters of galaxies, voids, and the first galaxies in the Universe - to understand galaxy astrophysics/star formation, dark energy, dark matter, cosmic inflation, and the reionization process in the early Universe.
Participant in the scientific projects 4MOST, BUFFALO, Euclid, and SKA Observatory. External Collaborator in the Dark Energy Survey. Also participating in the scientific exploitation of data from the Hubble Space Telescope and the coming James Webb Space Telescope.
Theoretical studies of the philosophy of cosmology, such as model inference, fine-tuning of the constants of nature, and multiverse explanations.

Publications
Recent publications
Part of Astronomy and Astrophysics, 2025
- DOI for Euclid preparation LV. Exploring the properties of proto-clusters in the Simulated Euclid Wide Survey
- Download full text (pdf) of Euclid preparation LV. Exploring the properties of proto-clusters in the Simulated Euclid Wide Survey
Euclid preparation LIV. Sensitivity to neutrino parameters
Part of Astronomy and Astrophysics, 2025
- DOI for Euclid preparation LIV. Sensitivity to neutrino parameters
- Download full text (pdf) of Euclid preparation LIV. Sensitivity to neutrino parameters
Euclid preparation: L. Calibration of the halo linear bias in Î(v)CDM cosmologies
Part of Astronomy and Astrophysics, 2024
- DOI for Euclid preparation: L. Calibration of the halo linear bias in Î(v)CDM cosmologies
- Download full text (pdf) of Euclid preparation: L. Calibration of the halo linear bias in Î(v)CDM cosmologies
Part of Astronomy and Astrophysics, 2024
- DOI for Euclid preparation: LI. Forecasting the recovery of galaxy physical properties and their relations with template-fitting and machine-learning methods
- Download full text (pdf) of Euclid preparation: LI. Forecasting the recovery of galaxy physical properties and their relations with template-fitting and machine-learning methods
Part of Astronomy and Astrophysics, 2024
- DOI for Euclid preparation XLVII. Improving cosmological constraints using a new multi-tracer method with the spectroscopic and photometric samples
- Download full text (pdf) of Euclid preparation XLVII. Improving cosmological constraints using a new multi-tracer method with the spectroscopic and photometric samples
All publications
Articles in journal
Part of Astronomy and Astrophysics, 2025
- DOI for Euclid preparation LV. Exploring the properties of proto-clusters in the Simulated Euclid Wide Survey
- Download full text (pdf) of Euclid preparation LV. Exploring the properties of proto-clusters in the Simulated Euclid Wide Survey
Euclid preparation LIV. Sensitivity to neutrino parameters
Part of Astronomy and Astrophysics, 2025
- DOI for Euclid preparation LIV. Sensitivity to neutrino parameters
- Download full text (pdf) of Euclid preparation LIV. Sensitivity to neutrino parameters
Euclid preparation: L. Calibration of the halo linear bias in Î(v)CDM cosmologies
Part of Astronomy and Astrophysics, 2024
- DOI for Euclid preparation: L. Calibration of the halo linear bias in Î(v)CDM cosmologies
- Download full text (pdf) of Euclid preparation: L. Calibration of the halo linear bias in Î(v)CDM cosmologies
Part of Astronomy and Astrophysics, 2024
- DOI for Euclid preparation: LI. Forecasting the recovery of galaxy physical properties and their relations with template-fitting and machine-learning methods
- Download full text (pdf) of Euclid preparation: LI. Forecasting the recovery of galaxy physical properties and their relations with template-fitting and machine-learning methods
Part of Astronomy and Astrophysics, 2024
- DOI for Euclid preparation XLVII. Improving cosmological constraints using a new multi-tracer method with the spectroscopic and photometric samples
- Download full text (pdf) of Euclid preparation XLVII. Improving cosmological constraints using a new multi-tracer method with the spectroscopic and photometric samples
Euclid preparation: XLVI. The near-infrared background dipole experiment with Euclid
Part of Astronomy and Astrophysics, 2024
- DOI for Euclid preparation: XLVI. The near-infrared background dipole experiment with Euclid
- Download full text (pdf) of Euclid preparation: XLVI. The near-infrared background dipole experiment with Euclid
Part of Astronomy and Astrophysics, 2024
- DOI for Euclid preparation: XLV. Optical emission-line predictions of intermediate-z galaxy populations in GAEA for the Euclid Deep and Wide Surveys
- Download full text (pdf) of Euclid preparation: XLV. Optical emission-line predictions of intermediate-z galaxy populations in GAEA for the Euclid Deep and Wide Surveys
Euclid preparation XLI. Galaxy power spectrum modelling in real space
Part of Astronomy and Astrophysics, 2024
- DOI for Euclid preparation XLI. Galaxy power spectrum modelling in real space
- Download full text (pdf) of Euclid preparation XLI. Galaxy power spectrum modelling in real space
Part of Monthly notices of the Royal Astronomical Society, p. 5267-5290, 2023
- DOI for The XMM cluster survey: exploring scaling relations and completeness of the dark energy survey year 3 redMaPPer cluster catalogue
- Download full text (pdf) of The XMM cluster survey: exploring scaling relations and completeness of the dark energy survey year 3 redMaPPer cluster catalogue
Euclid: Forecasts from redshift-space distortions and the Alcock-Paczynski test with cosmic voids
Part of Astronomy and Astrophysics, 2022
Velocity dispersions of clusters in the Dark Energy Survey Y3 redMaPPer catalogue
Part of Monthly notices of the Royal Astronomical Society, p. 4696-4717, 2022
Part of Monthly notices of the Royal Astronomical Society, p. 3030-3044, 2022
- DOI for Conditions for detecting lensed Population III galaxies in blind surveys with the James Webb Space Telescope, the Roman Space Telescope, and Euclid
- Download full text (pdf) of Conditions for detecting lensed Population III galaxies in blind surveys with the James Webb Space Telescope, the Roman Space Telescope, and Euclid
Euclid: cosmological forecasts from the void size function
Part of Astronomy and Astrophysics, 2022
- DOI for Euclid: cosmological forecasts from the void size function
- Download full text (pdf) of Euclid: cosmological forecasts from the void size function
Part of Monthly notices of the Royal Astronomical Society, p. 657-674, 2022
- DOI for The XMM Cluster Survey: an independent demonstration of the fidelity of the eFEDS galaxy cluster data products and implications for future studies
- Download full text (pdf) of The XMM Cluster Survey: an independent demonstration of the fidelity of the eFEDS galaxy cluster data products and implications for future studies
Environmental dependence of X-ray and optical properties of galaxy clusters
Part of Monthly notices of the Royal Astronomical Society, p. 1953-1963, 2021
Galaxy population constraints on cosmology and star formation in the early Universe
Part of The Astrophysical Journal, 2021
Part of \mnras, p. 4591-4606, 2020
- DOI for Stellar mass as a galaxy cluster mass proxy: application to the Dark Energy Survey redMaPPer clusters
- Download full text (pdf) of Stellar mass as a galaxy cluster mass proxy: application to the Dark Energy Survey redMaPPer clusters
Part of Publications Astronomical Society of Australia, 2020
Part of Monthly notices of the Royal Astronomical Society, p. 855-870, 2020
4MOST: Project overview and information for the First Call for Proposals
Part of The Messenger, p. 3-11, 2019
4MOST Consortium Survey 5: eROSITA Galaxy Cluster Redshift Survey
Part of The Messenger, p. 39-41, 2019
4MOST Consortium Survey 8: Cosmology Redshift Survey (CRS)
Part of The Messenger, p. 50-53, 2019
Mass variance from archival X-ray properties of Dark Energy Survey Year-1 galaxy clusters
Part of Monthly notices of the Royal Astronomical Society, p. 3341-3354, 2019
Part of Monthly notices of the Royal Astronomical Society, p. 1-17, 2019
- DOI for Galaxies in X-ray selected clusters and groups in Dark Energy Survey data - II. Hierarchical Bayesian modelling of the red-sequence galaxy luminosity function
- Download full text (pdf) of Galaxies in X-ray selected clusters and groups in Dark Energy Survey data - II. Hierarchical Bayesian modelling of the red-sequence galaxy luminosity function
Dark Energy Surveyed Year 1 results: calibration of cluster mis-centring in the redMaPPer catalogues
Part of Monthly notices of the Royal Astronomical Society, p. 2578-2593, 2019
Cluster-void degeneracy breaking: Neutrino properties and dark energy
Part of Physical Review D. Particles and fields, 2019
Cluster-void degeneracy breaking: Modified gravity in the balance
Part of Physical Review D. Particles and fields, 2018
The XXL survey: First results and future
Part of Astronomical Notes - Astronomische Nachrichten, p. 334-341, 2017
Part of Montly notices of the royal astronomical society, p. 413-428, 2016
The XMM Cluster Survey: the halo occupation number of BOSS galaxies in X-ray clusters
Part of Monthly notices of the Royal Astronomical Society, p. 1929-1943, 2016
Articles, review/survey
Fundamental physics with the Square Kilometre Array
Part of Publications Astronomical Society of Australia, 2020
Chapters in book
On Probability and Cosmology: Inference Beyond Data?
Part of The Philosophy of Cosmology, p. 429-446, Cambridge University Press, 2017