What: phenomgrav astrophysics seminar

When: Mar 30th, 2026, 14:00-15:00 CET

Where: Building C - Room 248  (first floor)

Speaker: Dr. Josiel Mendonça Soares de Souza -  Universidade Federal do Rio de Janeiro (Brazil)

Title: Beyond the Fisher Approximation in Gravitational Wave Data Analysis

Abstract: In the next decade, new gravitational-wave detectors (like Einstein Telescope and Cosmic Explorer) will operate with a sensitivity gain of about one order of magnitude compared to current instruments. This improvement will enable the detection of binary black hole coalescences up to redshift z∼10, as well as hundreds of merger events per month. Such capabilities will make these detectors powerful instruments for cosmology. The main challenge lies in data analysis: Bayesian inference of binary black hole signals requires exploring a 15-dimensional parameter space with highly complex waveform models. One possible way to address this problem is to rely on approximate methods, such as the Fisher approach, which assumes that gravitational-wave posteriors are Gaussian. However, this approximation fails when the posteriors exhibit multimodality or strong non-Gaussian features. This limitation can be alleviated by including higher-order terms in the Taylor expansion of the log-likelihood. In this work, we demonstrate the effectiveness of the DALI (Derivative Approximation for Likelihoods) approach, which provides reliable gravitational-wave posteriors while remaining computationally efficient.

What: Astrophysics Colloquium

When: Feb 24th, 2026, 15:00-16:00 CET 

Where: Building C - Room 131  (ground floor)

Speaker: Dr. Michele Bellazzini, INAF (Bologna)

Title: Tales of small things: dwarf galaxies as probes of galaxy formation

Abstract: Dwarf galaxies are widely studied systems as they bring key constraints on the process of galaxy formation. They are the most dark-matter dominated stellar systems and ideal sites to study the effect of internal (e.g., feedback) and external (environment) factors on the evolution of galaxies. In this talk, I will report on some dwarf galaxy projects I am carrying on, with particular emphasis on SSH, a survey aimed at searching for the signature of recent interaction/merging in isolated dwarf galaxies. The underlying goal is to begin to verify if hierarchical merging is indeed at work, also at the lowest galaxy mass scales, as predicted by the Lambda-CDM model.

What: phenomgrav astrophysics seminar

When: Jan 8th, 2026, 15:00-16:00 CET

Where: Building C - Room 248  (first floor)

Speaker: Dr. Mauro Pieroni, Instituto de Estructura de la Materia (IEM-CSIC), Madrid

Title: Simulation-Based Inference for Stochastic Gravitational Wave Background Reconstruction

Abstract: Simulation-Based Inference (SBI), also known as likelihood-free inference, is an alternative to traditional Monte Carlo techniques for performing Bayesian inference. SBI typically relies on machine learning methods to approximate the posterior distribution of model parameters given observed data. In recent years, SBI has been applied to a wide range of problems in physics, including gravitational wave (GW) astronomy. In this talk, I will review the basic principles of SBI and discuss its application to the detection and characterization of stochastic gravitational wave backgrounds with LISA.

For previous seminars, see here.