arXiv subjects

Giona Sala

Publications and source records attributed to Giona Sala.

3 recordsLinked to original sources

arXiv2026

Cosmology beyond standard sirens: cross-correlation of gravitational waves and neutral hydrogen intensity mapping

We explore the potential of cross-correlation between gravitational wave (GW) events and neutral hydrogen (HI) intensity mapping surveys to serve as an independent cosmological probe. Focusing on the ET and the SKAO, and assuming that binary black hole mergers and HI emission are biased tracers of the underlying dark matter distribution, we use their angular auto- and cross-correlation spectra to constrain cosmological parameters. We test three different GW detector networks: ET alone, both in its $Δ$ and 2L configuration, and ET-2L together with Cosmic Explorer. We show that the cross-correlation method, by naturally mitigating tracer-specific systematics, yields robust cosmological bounds, allowing for a sub-percent ($\sim 0.5\%$) precision on the Hubble constant $H_\mathrm{0}$. Furthermore, this approach robustly constrains the cosmic expansion history throughout the post-reionization era of the Universe and, unlike conventional standard sirens, simultaneously probes the large scale distribution of matter perturbations, achieving relative uncertainties of approximately 1.3% on the total matter density $Ω_\mathrm{m}$ and 1.6% on the late-time clustering amplitude $σ_8$.

astro-ph.CO↗

arXiv2026

Inferring cosmological parameters from galaxy and dark sirens cross-correlation

The number of observed gravitational wave (GW) events is growing fast thanks to rapidly improving detector sensitivities. GWs from compact binary coalescences like Black Holes or Neutron Stars behave like standard sirens and can be used as cosmological probes. To this aim, generally, the observation of an electromagnetic counterpart and the measurement of the redshift are needed. However, even when those are not available, it is still possible to exploit these "dark sirens" via statistical methods. In this work, we explore a method that exploits the information contained in the cross-correlation of samples of GW events with matter over-density tracers like galaxy catalogues. Contrary to other currently employed dark-sirens methods, this approach does not suffer from systematic errors related to the incompleteness of the galaxy catalogue. To further enhance the technique, we implement tomography in redshift space for the galaxy catalogue and luminosity distance space for the GWs. We simulate future data collected by the array of currently existing detectors, namely LIGO, Virgo, and Kagra, as well as planned third-generation ones such as the Einstein Telescope and Cosmic Explorers. We cross-correlate these data with those from upcoming photometric galaxy surveys such as Euclid. We perform a sensitivity forecast employing a full-likelihood approach and explore the parameter space with Monte Carlo Markov Chains. We find that with this method, third-generation detectors will be able to determine the Hubble constant $H_0$ with an error of only 0.7%, which is enough to provide decisive information to shed light on the Hubble tension. Furthermore, for the other cosmological parameters, we find that the GWs and galaxy surveys information are highly complementary, and the use of both significantly improves the ability to constrain the underlying cosmology.

astro-ph.CO↗

arXiv2026

Detecting White Dwarf Binary Mergers with Gravitational Waves

Mergers of white dwarf binaries are a possible progenitor channel for Type Ia supernovae. While white dwarfs are abundant in the universe and relatively well understood, their gravitational wave signals have not yet been directly observed. In order to detect gravitational waves from merging white dwarf binaries, a detector in the mid-band between LVK and LISA appears necessary. In this paper, we compute and discuss the gravitational waves emitted by inspiraling and merging white dwarf binaries, and assess their detectability with proposed space-based atom-interferometer detectors such as MAGIS Space and AEDGE. Gravitational waves from massive white dwarf binaries can be observed for many years before merger, offering a unique early warning of their final explosion. Our projections suggest that MAGIS Space could detect signals from Type Ia supernova progenitors at least once every four years, while AEDGE could observe at least a few hundred such events annually. The prolonged gravitational wave emission captured by atom-interferometers provides precise sky localisation and can allow observation of the final explosion with electromagnetic telescopes. The combined observation with electromagnetic radiation from the white dwarf binary coalescence could open a new pathway for multi-messenger astronomy involving some of the brightest transient events in the universe.

gr-qc↗