Cosmic Flows 2025: Probing the Universe with Peculiar Velocities

Session

Session 4

4 Feb 2025, 08:30

Tamborine Mountain Glades (Brisbane, Australia)

Conveners

Session 4: Tuesday

• Jenny Sorce

47. Peculiar Velocity Reconstruction from Simulations and Observations Using Deep Learning Algorithms

Yuyu Wang

04/02/2025, 08:30

In this paper, we introduce a U-Net model of deep learning algorithms for reconstructions of the 3D peculiar velocity field, which simplifies the reconstruction process with enhanced precision. We test the adaptability of the U-Net model with simulation data under more realistic conditions, including the redshift space distortion effect and halo mass threshold. Our results show that the U-Net...

13. Identification of basins of attraction in the local Universe & more

Aurélien Valade

04/02/2025, 09:00

Scarce, anisotropic, extremely noisy and prone to various biases: peculiar velocity surveys are not trivial to interpret. In this talk, I'll present HAMLET, a powerful GPU-oriented code that implements a field-level forward modeling method, which enables the reconstruction of the matter distribution in the Local Universe and the large scale motion associated to it. An application to the 38,000...

58. From Initial Conditions to Peculiar Velocities: A Bayesian Field-Level Approach to the Nearby Universe

Prof. Jens Jasche (Stockholm University)

04/02/2025, 09:30

The study of peculiar velocities provides a unique window into the dynamics of the nearby universe, allowing us to probe the non-linear regime of cosmic structure formation and test fundamental physics related to the Universe's expansion. As observational data quality and scale improve, modeling the nearby universe becomes more complex, requiring techniques that capture the non-linear dynamics...

9. Cosmicflows-4 Cosmography

Daniel Pomarède

04/02/2025, 10:00

The Cosmography inferred for the Cosmicflows-4 Catalog of 56000 peculiar velocities is presented, expanding on the HMC reconstruction recently published in Valade et al, Nature Astronomy (2024). Beside the 3D mapping of the overdensity and velocity fields, a map of the V-Web is constructed by analysis of the eigenvalues of the shear tensor. Earlier findings in the structure of the Cosmic...