Exploring the environment of black holes merger and its connection with gravitational waves

Core-collapse supernovae are the final, explosive demise of massive stars and are responsible for black hole formation. As a consequence of the prevalence of binarity amongst massive stars, they provide the leading progenitor channel of producing compact object binary systems with two black holes. General Relativity tells us that their binary orbit will shrink owing to energy losses via gravitational-wave (GW) emission. Following this shrinking, during the final few orbits, a prominent gravitational waveform is produced. Mergers of compact binaries therefore represent the true final fates of massive stars. However, unlikely mergers where a neutron star is involved, there is no electromagnetic emission arising from the merger of two black holes due to their intrinsic nature. Hence, any effort to link any gravitational waveform produced by a black holes merger to astrophysical information and/or its progenitor stars has produced null results.

The LIGO/Virgo collaboration has recently entered its third observing season and up to nowadays, they detected more than 20 gravitational wave events from merging binary black hole systems. More will come in the future thanks to the improved sensibility. Cardiff University is full member of the LIGO/Virgo collaboration and has preferential access to the gravitational-wave discovery and their information. Cardiff University is also part of the largest European endeavour in gathering astrophysical information from any compact merger producing GWs (ENGRAVE collaboration). Hence, the PhD student taking up this project will be in a unique position to get the most from two different approaches and collaborations.

The project will focus on the environment of black-hole mergers, which is the only way to retrieve useful astrophysical information from such events. The project will focus on retrieving information on galaxies in the likelihood region of previous GW mergers via electromagnetic spectroscopy (for the distant events) and integral-field spectroscopy (for the closest events). The latter allows for a spatially-resolved investigation of the surrounding stellar populations and provide constraints on the formation scenario of the binary and the 3D position of the merger in the galaxy harbouring the gravitational-wave event. Machine learning approaches will then be used to retrieve any link between the environmental information and those retrieved from the waveform. If the dataset will be rich enough, an Artificial intelligence algorithm can be built to predict what kind of galaxy will likely be the host of future, far black hole mergers.

In this project, the PhD student will gather knowledge of GW physics, astrophysics of galaxies and stellar evolution. From the computational side, the student will acquire programming skills in python and machine learning techniques and environments. Experience in observational astronomy and statistics are ‘de facto’ outcomes of such project.

This project will be funded by the STFC.
Applicants should apply to the Doctor of Philosophy in Physics and Astronomy with a start date of 1st October 2020.
https://www.cardiff.ac.uk/study/postgraduate/research/programmes/programme/physics-and-astronomy

In the research proposal section of your application, please specify the project title and supervisors of this project. If you are applying for more than one project, please list the individual titles of the projects in the text box provided. In the funding section, please select ’I will be applying for a scholarship/grant’ and specify that you are applying for advertised funding from the STFC.

Applicants will need to submit the following documents with their application:
- post high school certificates and transcripts to date
- academic CV
- personal statement
- two academic references. Your references can either be uploaded with your application, or emailed by the referee to [Email Address Removed] or [Email Address Removed]