Towards a Mapping Between Supernovae and Their Progenitors

Hinds, K-R ORCID: 0000-0002-0129-806X (2025) Towards a Mapping Between Supernovae and Their Progenitors. Doctoral thesis, Liverpool John Moores University.

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Abstract

Core-collapse supernovae, the explosive deaths of massive stars exceeding ~$M⊙, exhibit remarkable diversity in their properties -- spanning a wide range of luminosities, timescales, morphologies, and spectral evolution. This diversity reflects poorly understood heterogeneity in progenitor physical properties, with enhanced pre-explosion mass-loss emerging as a key driver of observed variations. While decades of detailed studies have characterised individual events, modern sky surveys like the Zwicky Transient Facility (ZTF) are now amassing large, homogeneous samples that are enabling novel statistical insights into the progenitor properties driving this diversity. The field stands at a transformative moment as upcoming surveys promise larger, more homogeneous supernova samples with enhanced temporal and wavelength coverage, enabling improved constraints on progenitor systematics and volumetric rates -- insights long sought but limited by small samples and observational biases.

This thesis leverages Gaussian process regression to analyse forced photometry light curves from the magnitude-limited ZTF Bright Transient Survey, and thereby construct one of the largest catalogs of CCSN parameters to date. By correlating empirical features measured from these light curves (e.g. rise times, peak luminosities and colours) with physical parameters from an extensive grid of hydrodynamical models varying in progenitor properties (circumstellar material structure, mass-loss rate and progenitor mass), I quantify the proportion of Type II SNe with sufficient pre-explosion mass-loss to alter their light curves. Out of the 377 spectroscopically classified events with well-sampled light curves, I find that 67 + 6% show evidence for substantial circumstellar material (MCSM ≥ 110-2.5 M⊙) within 1015 cm of the progenitor at explosion. After applying volumetric corrections, I find that 36{+5}_-7% of all Type II progenitors possessing dense circumstellar material at this radius. This high fraction of progenitors with dense circumstellar material, supported by both photometric and spectroscopic evidence of previous supernovae, reveals mass-loss rates significantly exceeding those observed in local group red supergiants or predicted by current theoretical models.

Additionally, this thesis investigates late-time radioactive 56Ni tails using an automated image-subtraction pipeline I developed for the Liverpool Telescope and expanded to multiple facilities. This analysis constrains synthesised 56 Ni masses for 136 Type II SNe, which probes explosion energies and mechanisms through enhanced late-time photometric coverage spanning multiple wavelengths. The weighted median $^{56}$ mass from the sample is MNi = 3.08{+1.66}_{-1.08}x10^{-2} M⊙ and 3.82+2.04_-1.33 x10-2 M⊙ (across two methodologies), aligning with literature values of 2 - 30x10-2 M⊙

These findings establish a framework for interpreting upcoming survey data from next-generation facilities that will probe fainter events and earlier explosion phases. This thesis advances our understanding of massive stars' final moments, linking pre-explosion activity to explosive outcomes and establishing a foundation for comprehensive models of CCSN diversity.

Item Type:	Thesis (Doctoral)
Uncontrolled Keywords:	mass-loss; massive stars; circumstellar mateiral; supernovae; transients; all-sky surveys
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Date of acceptance:	4 August 2025
Date of first compliant Open Access:	10 September 2025
Date Deposited:	10 Sep 2025 15:28
Last Modified:	10 Sep 2025 15:29
DOI or ID number:	10.24377/LJMU.t.00027122
Supervisors:	Perley, D, Copperwheat, C and Martig, M
URI:	https://researchonline.ljmu.ac.uk/id/eprint/27122

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