Symmetries are ubiquitous in modern physics. They not only allow for a more simplified description of physical systems but also, from a more fundamental perspective, can be seen as determining a theory itself. In the present paper, we propose a new definition of asymptotic symmetries that unifies and generalizes the usual notions of symmetry considered in asymptotically flat spacetimes and...
The spectral siren method is a promising new way to constrain cosmological parameters, providing a way to break the redshift degeneracy from cosmic distance measurements obtained from Gravitational Wave observations by using information from the mass distribution of the BBH population. There has been a recent development in MCMC methods to jointly constrain the cosmological and BBH population...
The Dark Energy Equation of State is not a direct observable. Some authors have suggested a connection between the Hubble tension and dynamical dark energy models, $w(z)$, supported by the recent DESI results, e.g., the CPL parameterization. Model-independent reconstructions — implemented with cubic splines, Gaussian processes, etc. — also suggest a dynamical behavior and generally make use of...
The Hubble constant is one of the most important cosmological parameters. However, current estimates diverge significantly: local measurements (e.g., SH0ES) suggest $H_0 \approx 73$ km/s/Mpc, while CMB-based results (e.g., Planck) yield $\approx 67$ km/s/Mpc — a tension of $4$–$5\sigma$. Several endeavors have been made to reconcile the two results. One of these attempts is the use of...
This work investigates cosmological parameters in the context of intrinsically symmetric models, a class of solutions in General Relativity that preserve local spatial symmetries while allowing for inhomogeneities and anisotropies. Unlike the standard model based on the FLRW metric, these models naturally include heat flux, anisotropic pressure, and dissipative effects, which can alter...
Laser Interferometer Gravitational Wave Observatories are instruments designed to detect gravitational waves. The detections made by LIGO confirmed the last remaining prediction of General Relativity and ushered in a new era of gravitational wave astrophysics. In order to improve sensitivity by an additional factor of two and to halve the low-frequency cutoff to 10 Hz, an upgrade to the LIGO...
This presentation provides an overview on the feasibility analysis of a novel suspension for the cryogenic test-mass mirrors of the low-frequency detector of the Einstein Telescope. To overcome the severe limitation imposed on traditional suspensions by the tensile stress for simultaneously achieving low thermal noise, safer mechanical margins and high thermal conductance, this configuration...
This work details a preliminary statistical analysis of non-gaussian noise anomalies, or glitches, within the Virgo observatory's data from the third observational run (O3). The methodology focuses on characterizing these glitches by analyzing their frequencies over time, signal-to-noise ratios (SNR), and frequency ranges to identify correlations and prevalent types. The primary goal is to...
The analysis of gravitational wave data requires precise methods for identifying and extracting astrophysical signals from instrumental noise. In this work, we employ open-source tools such as GWpy and PyCBC to process real data from the LIGO–Virgo collaboration. For the GW170817 event, associated with the merger of two neutron stars, we applied the Q-transform for time–frequency...
We analytically investigate the effects of gravitational waves on the Casimir force between two uncharged metallic plates. The gravitational contribution to the electromagnetic vacuum energy is computed using covariant path integral quantization in a gravitational wave background. Our findings reveal that gravitons are absorbed by the cavity, inducing a repulsive correction to the Casimir...
Following the detection of GW150914 by LIGO, General Relativity (GR) has solidified its status as a definitive theory of gravity. However, in certain regimes—particularly at high energies—modifications to the Einstein-Hilbert action have been proposed. Terms such as the Starobinsky correction ($R^2$), as well as higher-order contributions like $R\Box R$, can robustly describe phenomena such as...
The Robinson-Trautman metrics represent the simplest scenario that can describe the emission of Gravitational Waves from a bounded source. Lowest-order perturbations of the Schwarzschild metric have been previously investigated by Kramer (1988) and several others, particularly in order to demonstrate that the radiating gravitational field is well-behaved and free of irregularities. But little...
The Advanced LIGO detectors are highly sensitive instruments designed for detecting gravitational waves. A critical challenge in maximizing detector uptime is the occurrence of "locklosses," which happen when the interferometer loses light resonance in one or more of its optical cavities, resulting in significant downtime required for re-acquisition. While some locklosses are attributed to...
Gravitational-wave (GW) astronomy has progressed steadily since the first detection of a signal from a binary black-hole coalescence in 2015, and in parallel, machine-learning techniques have become increasingly valuable allies in this field, enabling more effective searches for different signal types and improving characterization of detector noise. Although all confirmed detections to date...
General Relativity (GR) has been consolidated as the most successful theory to describe gravitation, having been confirmed by numerous experiments, most notably the direct detection of gravitational waves. However, GR presents limitations in different regimes: on cosmological scales, dark matter and dark energy are invoked to explain observational phenomena; on microscopic scales, the absence...
We report new developments in the L2D+GWPM procedure
for sky localization using two detectors and gravitational-wave
polarization modes measurement.
We review the new findings presented in
https://doi.org/10.1007/s10509-025-04465-0,
where we report the first direct measurement
of spin-2 gravitational-wave polarization modes.
We present validation of the procedure using injected...
The detection of gravitational waves (GWs) by detectors such as LIGO has opened a new path for the observation of astrophysical objects [1].
In this context, we highlight compact stars as a source of GWs via their pulsation modes, in particular the non-radial f-mode which is very sensitive to the equation of state (EoS) of the star, which is composed of ultra-dense matter [2]. This means that...
As electromagnetic and gravitational-wave observations expand our ability to study compact objects such as black holes and neutron stars, considerable effort has been devoted to testing general relativity and its alternatives in the strong-field regime that characterizes their vicinities. A paradigmatic phenomenon in this context is the scalarization effect, in which the scalar field present...
The last decade saw huge progress in gravitational wave astronomy. The recent observed signals — from LIGO to NanoGrav — have opened a new window with rich information regarding our universe, while also allowing to test and constrain cosmological models. In this context, we analyze the production of Primordial Gravitational Waves (PGW's) from the vacuum fluctuations of a pre-Big Bang...
A equação de Klein-Gordon-Fock (KGF) em espaços-tempo curvos fornece insights cruciais sobre as interações entre matéria e geometria dinâmica. Em ondas gravitacionais, soluções analíticas revelam fenômenos curiosos: Gibbons (1975) demonstrou que ondas planas exatas preservam simetrias de Killing, suprimindo completamente a produção de partículas do vácuo. Duas décadas depois, Garriga &...
Gravitational wave (GW) events have raised important and challenging questions for models of stellar and binary evolution. While diverse results have provided valuable insights into the formation of compact binaries, a complementary approach is to investigate the properties of the host galaxies where these events are more likely to occur. This perspective can help us constrain formation...
