GDR CoPhy Episode 4

Session

Tuesday Afternoon

2 juin 2026, 16:30

Clermont Ferrand

57. Future missions for CMB spectral distortion measurements

Xavier Coulon (IAS-CNRS)

02/06/2026 16:30

The only precise measurement of the cosmic microwave background (CMB) spectrum to date was achieved by COBE-FIRAS in the early 1990s, showing that it is close to a perfect blackbody emission. However, both standard and non-standard physical processes inevitably generate small deviations from this spectrum, known as CMB spectral distortions. They provide a powerful and unexplored probe of the...

39. WG TOOLS

Guilhem LAVAUX (IAP, CNRS INSU)

02/06/2026 17:00

52. No supernovae? Measuring H₀ from Cepheids, TRGB stars, and masers with BORG peculiar velocities

Richard Stiskalek (Oxford University)

02/06/2026 17:30

The Hubble tension demands fresh, independent routes to H₀. I present two-rung and one-rung distance ladders that bypass Type Ia supernovae entirely, connecting Cepheid and TRGB distances, as well as geometric maser distances, directly to cosmological redshifts. The first two-rung ladder uses the SH0ES Cepheid sample with Milky Way, LMC, and NGC 4258 anchors, yielding H₀ = 71.7 ± 1.3 km/s/Mpc...

63. Simulation-Based Inference (SBI) for cosmology with type Ia Supernovae (SNe Ia).

Adam TRIGUI (IP2I)

02/06/2026 18:00

Systematic uncertainties associated to calibration, selection functions and astrophysical effects are dominating the error budget of SNe Ia cosmology. Correction methods applied to account for these systematics, and especially for the complex combination of selection functions and astrophysical variability, are questionable, particularly given the current H0 and Λ tensions for which SN Ia data...