Swiss Cosmology Days 2025 - ETH Zurich

Session

LSS Measurements

Jun 5, 2025, 10:00 AM

Siemens Auditorium (HIT E 51) (ETH Zurich)

26. Impact of Line-of-Sight Structure on Galaxy Cluster Weak Lensing Mass and Concentration

Felix Vecchi (EPFL)

6/5/25, 10:00 AM

LSS Measurements

The all sky telescope, Euclid, will use weak lensing measurements of the distribution of matter in galaxy clusters to constrain cosmology. However, lensing is sensitive to all mass projected along the line-of-sight, meaning that intervening structures introduce systematic uncertainties. In this talk, I will show how we use the highest-resolution FLAMINGO hydrodynamical simulation to construct...

6. A Webb View of the COSMOS Field

David Harvey (EPFL)

6/5/25, 10:15 AM

LSS Measurements

The 2 square degree COSMOS field has been responsible for a host of exciting scientific discoveries, including some of the first studies of tomographic weak lensing. Now with the next generation James Webb Telescope we are able to see the COSMOS in a whole new light. With unprecedented depth, JWST enables weak lensing galaxy densities of over 120 galaxies per square arc-minute and unparalleled...

9. Toward Robust Measurements of Relativistic Effects in Galaxy Clustering with DESI and Euclid

Francesca Lepori (University of Zurich)

6/5/25, 10:30 AM

LSS Measurements

Gravitational redshift and Doppler effects give rise to an antisymmetric component of the galaxy correlation function when cross-correlating two galaxy populations or different tracers. Relativistic effects can be isolated from density and redshift space distortions (RSDs) clustering signals by splitting the galaxy population into two catalogs and using adapted estimators, such as the dipole...

33. Multi-Probe Large-Scale Structure Cosmology with Simulation-Based Inference and Deep Learning

Jozef Bucko (ETH Zurich)

6/5/25, 10:45 AM

LSS Measurements

Progress in computing and machine learning has enabled an efficient extraction of information from cosmological fields beyond the Gaussian regime. In our work, we investigate the potential of combining non-Gaussian information from weak lensing and galaxy clustering observations to improve constraints on cosmological parameters. We develop a forward model based on the CosmoGrid simulation...

25. The Dark Energy Survey Year 6 3x2pt: Multi-Probe Modeling Strategy and Validation

David Sanchez Cid (University of Zurich)

6/5/25, 11:00 AM

LSS Measurements

The Dark Energy Survey (DES) is preparing to release its Legacy cosmological analysis based on six years of observations, comprising shape and position measurements for over 130 million galaxies across 5,000 square degrees. This unprecedented dataset enables a powerful joint study of weak gravitational lensing and galaxy clustering—commonly referred to as the 3×2pt analysis—to robustly...

21. DESI Part 1: Overview of the DESI survey and clustering measurments from DR1&DR2

Antoine Rocher (EPFL)

6/5/25, 11:15 AM

LSS Measurements

The Dark Energy Spectroscopic Instrument (DESI) collaboration is conducting a five-year redshift survey of over 40 million galaxies. By targeting four different galaxy tracers, bright galaxies, luminous red galaxies, emission line galaxies and quasars across a large redshift range 0.1<z<3.5, DESI is designed to measure the expansion history of the Universe using Baryon Acoustic Oscillations...

22. DESI Part 2: Cosmological Implication of DR1&DR2 measurements

Rafaela Gsponer (EPFL)

6/5/25, 11:30 AM

LSS Measurements

The Dark Energy Spectroscopic Instrument (DESI) is conducting a five-year spectroscopic survey of 40 million galaxies and quasars, designed to map the cosmic expansion history and the growth of large-scale structure across the redshift range 0.1<z<3.5. Over the past year, the collaboration has released measurements of the baryon acoustic oscillation (BAO) scale from galaxies, quasars, and the...

31. Reconstructing the dark energy density in light of DESI BAO observations

Maria Berti

6/5/25, 11:45 AM

LSS Measurements

In light of the evidence for dynamical dark energy (DE) found from the Dark Energy
Spectroscopic Instrument (DESI) baryon acoustic oscillation (BAO) measurements, we perform
a non-parametric, model-independent reconstruction of the DE density evolution. To do so, we
develop and validate a new framework that reconstructs the DE density through a third-degree
piece-wise polynomial...

34. Robust cosmology through combined probes

Alexander Reeves (ETHZ)

6/5/25, 12:00 PM

LSS Measurements

As wide-field surveys yield increasingly precise data, multiprobe analyses offer significant advantages. In this talk, I will discuss our study in which we use a previously developed framework to analyze combinations of three CMB (Planck PR3, Planck PR4, and ACT+WMAP) datasets, DESI Y1 Baryon Acoustic Oscillation (BAO) data, and a 9 × 2pt low-z dataset comprising KiDS-1000, BOSS DR12, and...