Population synthesis is a crucial tool for studying the predictions of binary evolution models on many astrophysical objects and transients of interest. In this study, we use the population synthesis code COMPAS to constrain the uncertain physics of binary mass transfer, using a locally complete sample of stripped-envelope supernovae. We argue that current evolutionary models are surprisingly...
Despite the increasing number of GW detections, the astrophysical origin of the Binary Black Hole (BBH) mergers detected by the LIGO and Virgo interferometers remains elusive. A promising formation channel for these BBHs is inside accretion discs around supermassive black holes, that power AGN. Investigating the spatial correlation between the positions of these potential host environments and...
Using BPASS, we have created population synthesis models for several types of stellar populations, including open clusters, globular clusters and the LMC. We focus particularly on the binaries in these populations that generate GWs which may be detectable by LISA, and we evaluate the detectability using LEGWORK. We find that MW globular clusters typically contain a few binaries in the LISA...
Recently the international pulsar timing array collaboration has announced the first strong evidence for an isotropic gravitational wave background (GWB). We propose that rapid small oscillations (wiggles) in the Hubble parameter would trigger a resonance with the propagating gravitational waves, leaving unique signatures in the GWB spectrum as sharp resonance peaks/troughs. The proposed...
We know very little about the first few seconds of the universe, beyond the very successful Big Bang nucleosynthesis. In those first instants, First Order phase transitions in the early plasma could have taken place and reshape the content of the plasma and spacetime. For the computation of baryogenesis, gravitational waves, dark matter production or even possibly PBH production, the...
We computed the spectrum of linearized gravitational excitations of black holes with substantial angular momentum in the presence of higher-derivative corrections to general relativity. We do so perturbatively to leading order in the higher-derivative couplings and to more than twelve orders in the black hole angular momentum. This allows us to accurately predict quasi-normal mode frequencies...
A major science goal of gravitational-wave (GW) observations is to probe the nature of gravity and constrain modifications to General Relativity. An established class of modified gravity theories are scalar-tensor models, which introduce an extra scalar degree of freedom. This affects the internal structure of neutron stars (NSs), as well as their dynamics and GWs in binary systems, where...
Future detections of gravitational waves originating from binary neutron star mergers or core-collapse supernovae offer the potential to gain unprecedented insights into the structure of matter at densities far beyond those probed by Earth-based experiments. In order to be able to identify the correct equation of state of matter, a template bank of waveforms has to be generated by general...
Modelling the gravitational-wave (GW) emission of core-collapse supernovae is needed to, e.g., relate a detected GW to the properties of its source or test different models. To obtain such models, we will use the GRMHD code Gmunu to study the effect of different parameters of the collapsing star on the waveforms.
Currently, calibration errors in gravitational wave detectors are often modelled through an amplitude scaling and time jittering. While this is a valid approximation for narrowband signals, it might not be sufficient for broadband signals such as core-collapse supernovae (CCSNe). In this work, we present a plugin for coherent WaveBurst that uses the most accurate estimates of calibration...
The increasing number of GW detections paves the road towards pinning down the values of the most important cosmological parameters, enabling us to do precision cosmology. This approach requires the careful mitigation of various systematic effects, which become more and more important as the accuracy of our cosmological inference grows. In this talk, I will present the UpGLADE galaxy...
Dark siren measurement of Hubble constant is one of the most exciting results in the multimessenger astronomy. Currently, the uncertainty of this measurement is dominated by the unknown gravitational wave events population. However with more events and better sensitivity of detectors, the uncertainty will shrink, therefore it is important to study impact of uncertainties from different...
Since the first detection, Gravitational Waves (GWs) have opened a new observational window on our Universe. When accompanied by an electromagnetic detection, GWs emitted by merging binaries of compact objects can be used as “standard sirens” to probe the distance-redshift relation and the standard model of cosmology. However, as in the case of light, we expect GW signals to be bent during...
In the era of large scale galaxy surveys, significant effort has been put in constraining cosmological models with unprecedented precision. In this context, gravitational waves (GW) might play a pivotal role to improve our understanding of the Universe. In particular, the clustering of gravitational waves potentially allows to constrain perturbation growth, similarly to galaxy clustering. As...
Over the past decades, observations have established a sample of more than 200 bright Active galactic nuclei (AGN), powered by accretion onto massive black holes, in the first billion years of the Universe. The James Webb Space Telescope has significantly revised this sample by yielding a sample of unexpectedly numerous and large black holes (up to a 100 million solar masses) within the first...
With the onset of next generation gravitational interferometers, we find ourselves in an era where we can peer into cosmic time and see the influence of mergers on the growth of supermassive black holes (SMBH). Here, we investigate properties of a cluster of intermediate-mass black holes surrounding a supermassive black hole. A model first proposed by Ebisuzaki et al. (2001) and for which...
GWcosmo is a package to estimate cosmological parameters using gravitational-wave observations with galaxy catalogues. Its current version for LVK Run O4 makes use of a precomputed ‘Line Of Sight Redshift Prior’, which encodes the redshift information of the galaxies and improves the computing time of the analysis.
Unresolved sources of gravitational waves can create a stochastic gravitational wave background (SGWB) which may have intrinsic or extrinsic anisotropies. The angular power spectrum is a well-suited estimator for characterizing diffuse anisotropic distributions in the sky. Here we estimate the first model-independent all-sky all-frequency SGWB angular power spectra in the 20-1726 Hz frequency...
