Cosmic Flows 2025: Probing the Universe with Peculiar Velocities

Session

Session 13

7 Feb 2025, 11:00

Tamborine Mountain Glades (Brisbane, Australia)

Conveners

Session 13: Friday

• Agne Semenaite (Swinburne University of Technology)

44. Investigating beyond $\Lambda$CDM using the state-of-art supernova sample from the Dark Energy Survey

Ryan Camilleri (The University of Queensland)

07/02/2025, 11:00

Type Ia Supernovae act as standard candles which provide a fundamental way to probe the expansion history of the Universe. While the standard cosmological model fits current data well, uncertainty remains. This uncertainty has led to a wealth of exotic cosmological models being proposed. In my work, I constrain a variety non-standard models using the DES 5-year sample - the largest single...

11. Understanding the role of peculiar velocities in void cosmology

Giulia Degni

07/02/2025, 11:20

Cosmic voids, large under-dense regions in the Universe, serve as promising laboratories for extracting cosmological information. They offer opportunities to explore deviations from $\Lambda$CDM and provide insights into dark energy and modification of gravity. Upcoming surveys will enable detailed void analyses, allowing access to a huge number of voids. Voids' significance lies in their...

5. The Cosmic Dipole Problem

Geraint Lewis

07/02/2025, 11:40

I will present our recent results exploring the integrity of the cosmological principle, the idea that, on sufficient scales, the universe is homogeneous and isotropic. Recent tensions have arisen between the dipole of cosmological sources and its interpretation from the CMB as a kinematic departure from the local Hubble Flow, bringing the cosmological principle into doubt. With a...

4. Measuring the growth rate from the SDSSv survey using auto- and cross- power spectrum of the galaxy density and momentum fields

Dr Fei Qin (CPPM)

07/02/2025, 12:00

The large-scale structure of the Universe and its evolution over time contains an abundance of cosmological information.One way to unlock this is by measuring the density and momentum power spectrum from the positions and peculiar velocities of galaxies, and fitting the cosmological parameters from these power spectrum.In this work, we will explore the cross power spectrum between the ...

18. Measuring the growth rate of structure from the Pantheon+ supernova sample

Anthony Carr (Korea Astronomy and Space Science Institute)

07/02/2025, 12:20

At low redshift, peculiar velocities are particularly well-suited to studying the nature of dark energy through the growth rate of structure. Supernovae Ia are precise distance indicators, and we can estimate peculiar velocities from their Hubble residuals at low-redshift, i.e., roughly their departure from motion caused purely by expansion. The Pantheon+ supernova sample is currently the most...