Swiss Cosmology Days 2025 - ETH Zurich

Session

H0 Measurement

Jun 5, 2025, 2:00 PM

Siemens Auditorium (HIT E 51) (ETH Zurich)

40. Opportunities and challenges in analyzing 10’000 gravitational lenses to shed light on dark matter and dark energy

Simon Birrer, Simon Birrer (Stony Brook University)

6/5/25, 2:00 PM

H0 Measurement

Strong gravitational lenses have provided great insights into the expansion history of the universe and the dark matter distribution from clusters down to sub-galactic scales.
Current state-of-the-art measurements involving strong gravitational lensing are based on samples of order a dozen gravitational lenses. This current decade, with the onset of wide and deep surveys, such as LSST, Euclid...

15. TDCOSMO 2025: Cosmological constraints from strong lensing time delays

Martin Millon (ETHZ)

6/5/25, 2:15 PM

H0 Measurement

Time-delay cosmography with lensed quasars is a one-step method for estimating the Hubble constant in the local Universe independently of the cosmic distance ladder. It does not require any intermediate calibration and relies on measuring the time delays between multiple images of strongly lensed quasars, which are inversely proportional to the Hubble constant.

In this talk, we present...

5. A consensus measurement of the local expansion rate of the Universe

Richard Anderson (EPFL)

6/5/25, 2:30 PM

H0 Measurement

The Hubble constant (H0) is crucial to the understanding of the Universe and its evolution. Hence, one would expect agreement on its value in an era of precision cosmology. However, improvements to direct H0 measurements have resulted in a growing discord with the cosmology-dependent predictions of H0 based on the Cosmic Microwave Background observed by the ESA Planck mission. Importantly,...