The GrEAT (Gravitational-wave Excellence through Alliance Training) synergy program on space-based gravitational-wave research will take place in the UK in November 2019.

The program will start with a week-long school on gravitational-wave astronomy. Students will then move on to the various UK nodes to complete longer projects.

The school will feature two introductory talks each morning and hands-on sessions in the afternoons.

Slides/notebooks are available here: https://github.com/dgerosa/greatnetworkschool

Monday October 28th

Venue: Edgbaston Park Hotel (Corelli Room)

• 9.00-9.30. Registration.

• 9.30-10.30. Alberto Vecchio. Gravitational waves across the frequencies.

• 10.30-11.00. Coffee break.

• 11.00-12.00. Silvia Toonen. White dwarfs in the gravitational-wave era.

• 12.00-14.00. Lunch break

• 14.00-15.00. Elinore Roebber and Haixing Miao. Introduction to hands-on session (see below)

• 15.00-17.00. Hands-on session

Tuesday October 29th

Venue: Edgbaston Park Hotel (Corelli Room)

• 9.30-10.30. Chris Moore. Data analysis: search and parameter estimation.

• 10.30-11.00. Coffee break.

• 11.00-12.00. Andreas Freise. Simulating interferometers.

• 12.00-14.00. Lunch break

• 14.00-17.00. Hands-on session

Wednesday October 30th

Venue: Staff house (J B Priestley Room)

• 9.30-10.30. Niels Warburton. Extreme mass-ratio inspirals.

• 10.30-11.00. Coffee break.

• 11.00-12.00. Denis Martynov. Instrumental challenges.

• 12.00-14.00. Lunch break

• 14.00-17.00. Hands-on session

Thursday October 31st

Venue: Edgbaston Park Hotel (Corelli Room)

• 9.30-10.30. Sean McGee. Supermassive black holes and synergies with X-ray missions.

• 10.30-11.00. Coffee break.

• 11.00-12.00. Antoine Klein. Time delay interferometry.

• 12.00-14.00. Lunch break

• 14.00-17.00. Hands-on session

Friday November 1ST

Venue: Staff house (J B Priestley Room)

• 9.30-10.30. Geraint Pratten. Waveform modeling and numerical relativity: what do we need?

• 10.30-11.00. Coffee break.

• 11.00-12.00. Davide Gerosa. Multiband gravitational-wave (astro)physics.

• 12.00-14.00. Lunch break

• 14.00-16.00. Hands-on session (student presentations)

Hands-on Sessions

During the conference afternoons, participants will have the opportunity to concentrate on either of these two projects:

• The angular resolution of Taiji to deci-Hertz gravitational waves; Elinore Roebber. This project will adapt existing codes to perform a fully Bayesian analysis on quasi-monochromatic GW signals with frequencies all the way up to 0.1Hz in Taiji. This project will aim to quantify both the sensitivity as well as the angular resolution of Taiji to such signals. (Theory)

• Time and frequency domain simulation of gravitational-wave detectors; Haixing Miao. Gravitational-wave detectors are large scale laser interferometers. Compared to simple Michelson interferometer, they use optical cavities to enhance the detector sensitivity. This project will simulate the behaviors of a single suspended optical cavity in both time and frequency domain. In particular, we will study how to use the error signal for locking the cavity around its working point. (Experimental)

After the school, students will spend 3-4 weeks to designated UK institutions to complete longer, more ambitious projects. The following projects have been offered. Students should specify their choice(s) in the registration form.

• Gravitational waves from stellar binaries; Birmingham, Silvia Toonen and Valeriya Korol. One of the most common types of binaries is a double white dwarf. They produce ample amounts of gravitational wave (GW) emission that can be observed with future space-based GW observatories. The inevitable merger of the two white dwarfs in the system typically occurs at decihertz frequencies (inaccessible for LISA). The mergers of double white dwarfs are linked to a variety of transients, with most importantly type Ia supernovae (SNIa). Even though SNIa have served as crucial tools to measure distance on cosmological scales, and the expansion of the universe itself, the progenitors of SNIa are still a mystery. In this project, we will study how many double white dwarfs we will be able to observe at decihertz frequencies and their potential to discover the illustrious progenitors of transients.

• Detectability of stellar-mass black-hole binaries from space; Birmingham; Davide Gerosa, Christopher Moore, and Antoine Klein. The progenitors of the high-mass black-hole mergers observed by LIGO and Virgo are potential sources for future space-based gravitational-wave detectors and promising candidates for multi-band observations. In this project, we investigate the minimum signal-to-noise ratio these sources must have to be detected by various proposed space missions.

• Time-domain simulation of gravitational-wave detectors (a continuation of the school project); Birmingham. Andreas Freise and Haixing Miao. Laser interferometric gravitational wave (GW) detectors, which recently made breakthrough discoveries, are km scale laser interferometers with kg suspended mirrors as the test masses. Compared to the interferometer first invented by Michelson, they include more mirrors to form optical cavities, which enhances the sensitivity to tiny GW signals. These cavities have a very small working range, orders of magnitude smaller than the wavelength of the light, while in reality the suspended mirrors move orders of magnitude larger than the wavelength. To bring the cavities, thereby the entire interferometer, eventually to the working point, we use sophisticated state-of-the-art sensing and control schemes. In this project, we will try to simulate highly nonlinear time-dependent behaviors of a simplified version of an interferometer, and try to understand how it transitions to the working point. This may lead to new insights into improving the control strategy. Students with general backgrounds are welcome. This project will involve both analytical and numerical analysis.

• Multi-band, multi-detector data analysis; Glasgow; Siong Heng and Chris Messenger. This project will use a Fisher matrix approach to explore the impact of multi-band analysis for a combination of space and ground based detectors. The ability for such detector networks to perform parameter estimation and localise source sky locations will be characterized.

• Exploring neutron star tides with advanced detectors; Southampton; Nils Andersson. The gravitational-wave signal from the late stages of a binary neutron star inspiral includes fine-print features associated with dynamical tides (often expressed in terms of excited neutron star oscillation modes). These features are unlikely to be detected by the instruments like advanced LIGO, but they may become relevant in the 3G era. The purpose of this project is to estimate the detectability of different proposed features for different proposed detectors configurations (Einstein Telescope, Cosmic Explorer...) and establish to what extent we will (at some point) be able to use such features to probe the physics involved.

• Ion beam deposition of SiOx and SiNx thin films for possible use in future GW detectors; Strathclyde - Glasgow; Stuart Reid, Paul Hill, Iain Martin, and Peter Murray. The aim of this project is to develop an ion beam deposition process which can be used to fabricate the next generation of mirror coatings for use in gravitational wave detectors. This will be a collaborative project managed by Strathclyde University and the University of Glasgow, with the successful student learning all steps of deposition and characterisation of thin film coatings. During the first two weeks, development of SiOx and SixNx thin film coatings will be undertaken, at Strathclyde, on one of the largest ion beam deposition tools in the world. Characterisation of these coatings will be carried out using spectrophotometry, and wavelength-dispersive x-ray spectroscopy; whilst room temperature ring down measurements will be used to determine the mechanical loss angle. In the final two weeks, the student will undertake cryogenic mechanical loss measurements (10 – 300 K) at the University of Glasgow on coated cantilever samples and absorption measurements, to investigate their suitability in any future cryogenic gravitational wave detector.

• Thin film deposition and characterisation in collaboration with UK industry; Strathclyde - Helia Photonics; Stuart Reid, Paul Hill, Caspar Clark. This project seeks to carry out optical characterisation, along with some thin film deposition, of thin film coatings relevant to laser damage applications. Significant time will be spent using a new RT Photon Spectrophotometer (195nm-5200nm) to study the bandgap and Erbach tail of typical dielectric coatings, and correlate to laser damage, mechanical loss and optical absorption.

• Mechanical loss and thin film deposition using novel evaporation and magnetron sputtering techniques at UWS; West Scotland; Carlos Garcia Nunez, Des Gibson, Shigeng Song. UWS hosts a vast array of thin film deposition techniques, and this project seeks to carry out thin film deposition and Q measurements relevant for mirror coatings for future ground based gravitational wave detectors.

• Building reduced order quadrature data for parameter estimation of super massive black hole mergers in LISA band; Cardiff; Qi and Raymond. The low frequency sensitivity on the order of 0.1mHz to 0.1 Hz in space-based GW detectors like LISA will use signals of very long durations. The high computational costs of parameter estimation with these long waveforms make it almost impossible with existing Bayesian inference pipelines. Reduced order modelling and reduced order quadrature (ROQ) integration rules have recently been exploited as promising techniques that can greatly reduce parameter estimation computational costs. In this 3-week student project, we use a recently developed Python-based ROQ building code named PyROQ to calculate the ROQ data required for the use of the ROQ rule in parameter estimation pipelines. Specifically, the student will be guided to build ROQ data for one of the LISA sources, i.e., super massive black hole mergers with black holes of masses 1e3 to 1e7 solar masses.

• Machine learning for long-duration GW transients from glitching pulsars; University of Portsmouth; David Keitel; Ian Harry ; Andrew Lundgren; Laura Nuttall. Many radio pulsars display enigmatic spin-up events, called glitches, which are also promising sources for long-duration gravitational-wave transients. However, these are likely too weak to detect with generic unmodelled searches, while matched filters based on simple models could easily miss more complicated signals. Robust machine learning / deep learning methods trained on a variety of simulated signals could be the solution. In this project, a student (ideally with some ML/DL background) will be the first to explore this novel application of methods which have already proven their promise for many other types of GWs.