This contribution presents preliminary results from IceCat-2, the second public catalog of IceCat Alert Tracks, which plans to build and improve upon the first release, IceCat-1. The initial catalog included all real-time alerts issued since 2016, as well as events observed by IceCube since the start of full-detector data collection in 2011 that would have triggered an alert if the program had...
After years studying broadband spectral distributions and trying to constrain theoretical models, a physicist can fall into a valley of scientific frustration. The recent multi messenger events brought a lot of excitement and new energies to face the old and new challenges of this often very abstract field of research. What can we learn from the past multiwalenght efforts and tools and what...
Since Virgo joined the O4 run in April 2024, the h(t) strain signal that may contain any gravitational wave signal has been reconstructed with a 2% accuracy in the 20-2000 Hz frequency band thanks to a good estimation of the interferometer optical response and the construction of accurate models of the mirrors actuators. I will present this h(t) reconstruction and how its current improvements,...
Observations of the early X-ray afterglow phases of Gamma-Ray Bursts (GRBs) using the Swift X-ray Telescope (XRT), which operates in the 0.3 to 10 keV energy range, have revealed distinct temporal features beyond those predicted by the standard forward shock afterglow model. Components in the XRT light curve, such as steep decay, flares, and plateaus, suggest more complex afterglow physics....
Accurate modeling of the early X-ray emission in short GRBs is essential for probing the GRB engine, understanding jet physics, and improving electromagnetic follow-up of gravitational wave signals from binary neutron star mergers in the context of multi-messenger astronomy. Thanks to the operation of the Swift satellite over the last 20 years, we now have access to an extensive archive of GRB...
We performed a study of the short gamma-ray burst (sGRB) population using a hierarchical Bayesian framework to constrain the (hyper-)parameters of the population model. We considered both an empirical luminosity function model and a more complex quasi-universal structured jet model of the luminosity distribution of the events across the population. Under the assumption of a compact binary...
The brightest Gamma-ray burst (GRB) ever, GRB 221009A, displays ultra-long GRB (ULGRB) characteristics, with a prompt emission duration exceeding 1000 s. To constrain the origin and central engine of this unique burst, we analyse its prompt and afterglow characteristics and compare them to the established set of similar GRBs. To achieve this, we statistically examine a nearly complete sample...
The nature of the remnant formed by the coalescence of two neutron stars (NS), is highly sensitive to both the initial mass and the equation of state of the progenitors. Traditionally, accreting black holes formed in the aftermath of NS mergers have been the prevailing central engine model to power short duration gamma-ray bursts (GRBs). However, this framework fails to explain the...
GW170817 is the first binary neutron star merger detected with gravitational and electromagnetic waves, and its afterglow is still detectable 7 yr post-merger. Some previous studies of the X-ray afterglow have claimed the onset of a new afterglow component or raised concerns about the data processing techniques. Motivated thus, we present here a reanalysis of X-ray afterglow data for GW170817...
