Workshop on Gravitational Wave Modelling

10 Oct 2022, 09:00 → 11 Oct 2022, 17:00 Europe/Madrid

Tomas Andrade

This workshop is devoted to the development and implementation of waveforms for gravitational wave data analysis, with particular emphasis on binary black hole mergers. We aim to push state of the art models used by the Ligo-Virgo-Kagra collaboration for detection and parameter estimation in preparation for the observing run O4.

 

Acknowledgements

This event is part of the grant CEX2019-000918-M funded by MCIN/AEI/10.13039/501100011033.

 

 

 

 

 

 

 

 

 

 

 

 

Organized by The Institute of Cosmos Sciences

 

 

 

 

 

Formulari_de_registre._Informacio_detallada_en.docx

Monday 10 October

1 Overview of gravitational-wave modelling

To date, all gravitational-wave detections accomplished by the LIGO-Virgo-KAGRA collaboration are compatible with compact binary merger events involving black holes and neutron stars in all three possible combinations. Signals from binary black hole (BBH) coalescences, however, are by far the most common and their modelling will be the focus of this presentation. The detection of BBH merger signals strongly relies on the use of template waveform banks against which conduct matched-filtering searches. Likewise, those templates are essential to infer the astrophysical properties of the sources generating the gravitational waves. This talk will present an overview of the approaches routinely employed in the complicated task of waveform modelling of BBH coalescences, both involving analytical relativity and numerical relativity, and will briefly discuss on possible alternative routes and the challenges awaiting just around the corner.

Speaker: Jose Antonio Font (University of Valencia)

talk-2022-Barcelona-Font.pdf

2 Rates and populations of dynamically formed binary black holes

In this contribution I present a fast population synthesis code for binary black holes (BBHs) formation and evolution in globular clusters (GCs) and use it to determine the redshift evolution of the merger rate density and masses of BBHs, with a particular focus on eccentric BBHs. A comparison to the merger rate reported by LIGO-Virgo shows that a scenario in which most of the detected BBH mergers with primary masses > 20Msun are formed in GCs is consistent with current constraints and requires initial GC half-mass densities >10^4 Msun/pc^3. The models can reproduce the masses in the pair-instability gap (> 50 Msun) with hierarchical mergers, if initial BH spins are negligible.

Speaker: Prof. Mark Gieles (ICC)

gw_iccub_mgieles.pdf

11:00 Coffee Break

3 Numerical information in analytical models

Speaker: Simone Albanesi (University of Turin, INFN section of Turin)

slides.pdf

4 Status TEOBResumS

Speaker: Rossella Gamba (Friedrich Schiller University Jena)

TEOB UB.pdf

13:00 LUNCH

5 Understanding analytical uncertainties within effective-one-body models

Speaker: Alessandro Nagar (INFN Torino)

6 Hands on

Speaker: Rossella Gamba (Friedrich Schiller University Jena)

Link to hands-on repo

TEOBResumS repository

Tuesday 11 October

7 A numerical-relativity gravitational-wave catalogue of spinning Proca-star collisions

I will present a systematic study of the dynamics and gravitational-wave emission of head-on collisions of spinning vector boson stars, known as Proca stars. To this aim we build a catalogue of about 800 numerical-relativity simulations of such systems. We have found that the wave-like nature of bosonic stars has a large impact on the gravitational-wave emission. In particular, we show that the initial relative phase ∆\epsilon = \epsilon_1 − \epsilon_2 of the two complex fields forming the stars (or equivalently, the relative phase at merger) strongly impacts both the emitted gravitational-wave energy and the corresponding mode structure. This leads to a non-monotonic dependence of the emission on the frequency of the secondary star ω2, for fixed frequency ω1 of the primary. This phenomenology, which has not been found for the case of black-hole mergers, reflects the distinct ability of the Proca field to interact with itself in both constructive and destructive manners. We postulate this may serve as a smoking gun to shed light on the possible existence of these objects.

Speaker: Dr Nicolas Sanchis-Gual

GW_Workshop_UB.pdf

8 Parameter estimation using the Newman-Penrose scalar and its applications: searching for boson-star mergers in LIGO-Virgo data

The detection and analysis of gravitational-wave signals relies on the comparison of the gravitational strain observed by the detectors (e.g. LIGO and Virgo) to theoretical templates for strain produced by given sources, e.g. black-hole mergers. Numerical simulations of compact-mergers, however, do not typically output the gravitational strain but a quantity known as the Newman-Penrose (NP) scalar. The obtention of the strain from the NP scalar is subject to well known systematic errors that are not trivial to ease. In this talk I will present a formalism that allows for the comparison of the detector data to the NP templates outputted by numerical simulations, which qualitatively removes a complete layer of errors. As an observational application, I will show a systematic comparison of high-mass events from LIGO and Virgo to numerical simulations of exotic compact objects known as (vector) boson stars, or Proca stars, providing estimates of the mass of the ultra-light bosons building up the stars together with a preliminary population study.

Speaker: Juan Calderon Bustillo (University of Santiago de Compostela)

11:00 Coffee Break

9 Black Hole Close Hyperbolic Encounters

There is evidence and theoretical reasons to believe that Black Holes can be densely clustered. Black holes in these dense clusters can gravitationally scatter off each other in hyperbolic encounters, emitting gravitational waves that could be observed by current detectors. In this talk we will discuss about the properties of these encounters as well as about the gravitational waves that are emitted and the signal we expect to observe in the network of gravitational wave detectors currently on Earth. We will also talk about how black holes can acquire a significant spin during these close hyperbolic encounters and its possible implications

Speakers: Gonzalo Morrás Gutiérrez (Universidad Autonoma de Madrid), Santiago Jaraba (IFT UAM-CSIC)

Slides Santiago Jaraba

WorshopGWModelling_BCN221011_GonzaloMorras.pdf

10 Numerical simulations for highly eccentric black hole binaries

Speaker: Tomas Andrade

13:00 Lunch

11 Discussion

15:30 Coffee End Sessions