arXiv subjects

Raphael Bertrand-Delgado

Publications and source records attributed to Raphael Bertrand-Delgado.

3 recordsLinked to original sources

arXiv2026

Reconstructing stochastic gravitational-wave signals from flavour deconstruction with LISA

We investigate the reconstruction of a stochastic gravitational-wave background generated by a first-order phase transition in flavour-deconstruction models using the Laser Interferometer Space Antenna (LISA). In these scenarios, the spontaneous breaking of an extended flavour-non-universal gauge symmetry at the TeV scale can both generate the observed hierarchies of Standard Model fermion masses and mixing angles and induce a strong first-order phase transition. We consider representative benchmark points of the model, compute the corresponding thermodynamic transition parameters, and construct the resulting gravitational-wave spectra using a state-of-the-art sound-wave template. We then inject these spectra into simulated LISA data and perform Bayesian inference with SGWBinner, jointly reconstructing the cosmological signal, instrumental noise, and astrophysical foregrounds. We find that the strongest benchmark signal can be successfully reconstructed, whereas weaker signals are substantially degenerate with the unresolved extragalactic compact-binary foreground. We further show that tighter prior information on this foreground, motivated by observations with ground-based detectors, can reduce this degeneracy and improve signal reconstruction. Our results demonstrate that flavour-deconstruction models can produce signals accessible to LISA, while highlighting the importance of astrophysical-foreground modelling for their identification and characterization.

astro-ph.CO↗

arXiv2026

Prospects for multi-messenger discovery of the gravitational-wave background anisotropies via cross-correlation with galaxies

We present new empirically grounded forecasts for the detectability of the stochastic gravitational-wave background anisotropies assuming a population of stellar-mass compact binary coalescences as its source. We quantified the discovery potential using simulations based on the Euclid Flagship Galaxy Catalogue and LIGO-Virgo-KAGRA observational constraints in combination with detailed theoretical modelling. We considered the multi-messenger cross-correlation with galaxies as well as the gravitational wave-only cross-correlation across observation-time bins. For compact binaries up to redshift $z<3$, we found that an angular resolution of $θ= 4.1$ deg ($\ell \geq 44$) is required for discovery within five years of observation via cross-correlation with a galaxy catalogue that is complete up to limiting magnitude $i < 24.7$ and has redshift uncertainties $σ_z = 0.003 (1+z)$. Extending the time range to ten years alleviates that requirement to $θ= 6.5$ deg ($\ell \geq 28$). We also showed that binning the galaxies in redshift allows us to reconstruct the evolution of the kernel, which can be used to further constrain compact binary population models. Discovery without a multi-messenger tracer has proven significantly more challenging, requiring exclusion of the loudest events, $θ= 1.8$ deg ($\ell \geq 95$), and a favourable coalescence rate. In light of the plans being carried out in the community for ongoing and upcoming galaxy surveys, this work bodes well for the multi-messenger discovery and exploration of the stochastic gravitational-wave background in the era of next-generation observatories such as the Einstein Telescope and Cosmic Explorer.

astro-ph.CO↗

arXiv2023

Spacecraft Charging of the Morazán MRZ-SAT Satellite in Low Earth Orbit: Initial Results on the Influence of Energetic Electron Anisotropy on Differential Charging

The advent of the modular CubeSat satellite architecture has heralded a revolution in satellite missions, drastically lowering the technical and financial barriers to space. Surface charging resulting from energetic electron poses a direct risk to satellites in space, causing electric arcing and breakdowns. This risk is exacerbated for small technology demonstration CubeSats that are less resilient than larger satellites. An upcoming CubeSat launch is the first CubeSat project originating from Honduras, the Morazán satellite (MRZ-SAT), due to launch in 2024. This will carry earth observational payloads to detect natural disasters. This study conducts simulations using the Electro-Magnetic Spacecraft Environment Simulator code to study absolute and differential charging of the MRZ-SAT cube-sat in Low Earth Orbit (LEO). The MRZ-SAT hosts four antennas, an architecture which lends itself well to studying and understanding differential charging in LEO. The MRZ-SAT was first simulated in a typical benign ionospheric plasma environment. Here the antenna located in the ambient plasma wake displayed the maximum charging up to --0.9 V, 0.24 V biased to the main cube. An energetic electron population was then included and the wake antenna subsequently charged to greater values of --2.73 V, now 1.56 V biased to the main cube. The anisotropy of the energetic electrons was then varied, and this differential charging trend appeared exacerbated with anisotropies of 0.5 to 0.05 inducing absolute wake antenna voltages up to --4.5 V and differential voltage biases 50 and 100 \% greater than when an isotropic population was considered. This study highlights the importance of electron anisotropy in LEO to surface charging and identifies this property in the energetic electron distribution functions as inducing potentially greater risks to satellites of electrical arcing and breakdown.

physics.space-ph↗