Supernovae are catastrophic stellar explosions shaping the visible Universe. They play an important role in the synthesis and distribution of almost all elements and especially heavy elements such as iron, enriching the Universe since the first supernova explosion when the cosmos was metal-free. We are now in the golden era of supernova astronomy - and in general of transients – since astronomical surveys are discovering roughly 20000 transients per year. Future astronomical experiments (for example the Large Survey of Space and Time - LSST) will boost the number of yearly discoveries by a factor of 100.
What happens when a star explodes into a dense circumstellar material? The faster moving ejecta will collide with slower moving circumstellar material (CSM), likely cause by mass loss via wind, stellar instability or because influenced by a companion star in a binary system. A forward shock is launched into the CSM, while a reverse shock moves back into the expanding material coming from the explosion. In the supernova electromagnetic spectra, multi-component line profiles in emission rise as a consequence of the multiple shocks investing the supernova and circumstellar medium. Sometimes, time-varying resonance lines in absorption of Calcium and Sodium (vastly present in the majority of stars) can be observed in supernovae that are ‘standard/normal’ at first glance but that harbour a hidden interaction with previously expelled material. A resonance line is the transitions between the ground state and the first energy level of an atom and, as the ground state is the most populated, those are usually the strongest lines. The analysis of such lines allow for a characterisation of the CSM mass, distance/location/geometry and velocity.
The scope of this PhD project is to identify and analyse such emission and absorption lines per supernova type (also those not obviously interacting) to create the first study of this type as function of core-collapse supernovae. This will unveil the nature of their progenitors, which has eluded our comprehension for decades!
In this project, the PhD student will gather knowledge of supernova explosions linked to the life and death of massive stars as well as programming skills in python and experience in observational astronomy, data reduction and data analysis.
Eligibility
The typical academic requirement is a minimum of a 2:1 a relevant discipline.
Applicants whose first language is not English are normally expected to meet the minimum University requirements (e.g. 6.5 IELTS) (https://www.cardiff.ac.uk/study/international/english-language-requirements)
How to apply
Applicants should apply to the Doctor of Philosophy in Physics and Astronomy.
Applicants should submit an application for postgraduate study via the Cardiff University webpages (https://www.cardiff.ac.uk/study/postgraduate/research/programmes/programme/physics-and-astronomy) including:
• your academic CV
• a personal statement/covering letter
• two references, at least one of which should be academic
• Your degree certificates and transcripts to date (with certified translations if these are not in English).
In the "Research Proposal" section of your application, please specify the project title and supervisors of this project.
This project is only available to self-funded students, please can you include your funding source in the "Self-Funding" section.