The 131-140th REM talks

The 132nd REM: Jun. 5th, 2025

Time: 11:00-12:00

Speaker: Ignacio Magaña Hernandez (Carnegie Mellon University)

Title: "Gravitational Wave Lensing: Current Status and Future Prospects"

Abstract:

Since the first detection of gravitational waves (GWs) from the merger of two stellar-mass black holes in 2015, the LIGO-Virgo-KAGRA (LVK) Collaboration has accumulated over 90 observations of mergers involving neutron stars and black holes. With upcoming observing runs for the LVK network of GW detectors, many more binary mergers are expected to be detected. The increasing size of gravitational wave catalogs has enabled the study of their population and its cosmic expansion history. In this talk, I will discuss the latest constraints on the BBH population, focusing on models that search for astrophysical subpopulations driven by various formation channels with both parametric and fully data-driven methods. Then, I will explain how the BBH mass spectrum can be used as a calibrating scale to measure cosmology—providing a GW data-only way to do cosmology. Lastly, I will demonstrate how using galaxy survey information as a prior on potential galaxy hosts for BBH mergers can improve our cosmological measurements.

The 131st REM: May. 19th, 2025

Time: 15:00-16:00

Speaker: Naoki Aritomi (U Tokyo)

Title: "Advanced LIGO detector performance in the fourth observing run"

Abstract:

I will talk about the LIGO detector performance in O4 based on the recently published paper, Phys. Rev. D 111, 062002 (2025).