LUMINOSITY DISTRIBUTIONS AND ABUNDANCE TOMOGRAPHY MODELLING OF TYPE IA SUPERNOVAE Christopher John Ashall A thesis submitted in partial fulfillment of the requirements of Liverpool John Moores University for the degree of Doctor of Philosophy 23rd Janurary 2017 Abstract I present an investigation into Type Ia Supernovae (SNe Ia). The aim of this inves- tigation is to explain the physics and diversity of SNe Ia, motivated by the fact that, although SNe Ia are known to come from a thermonuclear explosion of a C+O Chan- drasekhar mass (Ch-mass) White Dwarf (WD), their exact explosion scenario is one of debate, and their full diversity is not fully understood. As SNe Ia are used as cos- mological distance probes, understanding their explosions and progenitors systems in more detail could have important consequences. To examine the diversity of SNe Ia, I first present a large sample analysis of their B and V - band light curves, separated by host galaxy type. A new method for calculating host galaxy extinction is implemented and the width luminosity relation (WLR) is examined. After correction for host galaxy extinction, ‘normal’ SNe Ia (∆m15(B) < 1:6 mag) fill a larger parameter space in the WLR than previously suggested. Even excluding fast declining SNe, ‘normal’ (MB < −18 mag) SNe Ia from Star forming (S- F) and passive galaxies are distinct. This may indicate that various progenitor channels are prevalent in different galaxy types. Furthermore, it was also confirmed that sub- luminous SNe Ia tend to favour passive galaxies, which implies that this subset of SNe Ia come from an older progenitor system. There was a lack of transition SNe Ia in the dataset used in this project. These are SNe Ia with a luminosity between normal and sub-luminous SNe Ia. Understanding transitional SNe Ia is important in determining 1 2 whether sub-luminous SNe Ia are a totally different population. With the aim of understanding how normal SNe explode, I first turn my attention to SN 2014J. SN 2014J was the closest type Ia in the last 410 years, and it was a once in a life time opportunity to study. Therefore, a detailed spectroscopic and photometric analysis and abundance stratification modelling of SN 2014J is presented. SN 2014J is a spectroscopically normal type Ia SN with a B band decline rate of 0.95 mag, before correction for extinction. It was located in the dusty starburst galaxy M82, and does not follow the average Galactic extinction law of Rv = 3:1. With the knowledge about the diversity of SNe Ia and the ability to carry out de- tailed modelling, SN 1986G was next chosen to be modelled. SN 1986G sits in an interesting area of parameter space in the WLR. It is located in the ‘gap’ between nor- mal and sub-luminous SNe Ia. It has been theorised that sub-luminous SNe Ia come from a different progenitor system than standard SNe Ia. Therefore, understanding SN properties in this ‘gap’ is important for determining at which point SNe Ia properties begin to diverge from the normal scenario. A full abundance tomography modelling of SN 1986G was carried out. It was found that this SN is a low energy Chandrasekhar mass explosion. It had 70% of the energy of a standard W7 model. These findings raise the possibility that only SNe Ia with very large decline rates deviate from a Chan- drasekhar mass. 3 It’s the little things that people do which makes the dif- ference. My little thing is understanding the Universe. - C. Ashall 2016 There is no passion in playing small, in settling for a life that is less than the one you are capable of living. - C. Ashall 2016 I always wonder why birds stay in the same place when they can fly anywhere on the earth. Then I ask my self the same thing. - Harun Yahya Acknowledgements First of all I would like to thank my supervisor Paolo Mazzali, without his great guid- ance and help I would not have been able to complete this thesis. I would also like to thank my parents, without their help in life I would not be where I am today. They have always been supportive and helped me with my studies. I am also giving a big thank you to my girlfriend Sophia, she has helped me throughout the whole of my PhD, and she was a good listener I needed some one. Thank you to my second supervisor Phil James who has helped me with my work, and helped me improve my poor english. Finally I would like to thank all of my PhD friends who helped me get through this process. I thoroughly enjoyed all of our political and philosophical debates. 4 List of Publications Luminosity distributions of Type Ia supernovae, Ashall, C.; Mazzali, P.; Sasdelli, M.; Prentice, S. J., MNRAS, 460, 3529A - 08, 2016 Photometric and spectroscopic observations, and abundance tomography modelling of the Type Ia supernova SN 2014J located in M82, Ashall, C.; Mazzali, P.; Bersier, D.; Hachinger, S.; Phillips, M.; Percival, S.; James, P.; Maguire, K., MNRAS, 445, 4427A - 12, 2014 Abundance stratification in Type Ia supernovae - V. SN 1986G bridging the gap be- tween normal and subluminous SNe Ia, Ashall, C,; Mazzali,P.; Pian,E.; James,P.; MN- RAS, 463, 1891A, 2016 A very luminous magnetar-powered supernova associated with an ultra-long -ray burst, Greiner, Jochen; Mazzali, Paolo A.; Kann, D. Alexander; Krhler, Thomas; Pian, Elena; Prentice, Simon; Olivares E., Felipe; Rossi, Andrea; Klose, Sylvio; Taubenberger, Ste- fan; Knust, Fabian; Afonso, Paulo M. J.; Ashall, Chris; et al., Nature, 523,189G 07, 2015- Contribution: Magnetar light curve modelling. 5 6 Breaking the colour-reddening degeneracy in Type Ia supernovae, Sasdelli, Michele; Ishida, E. E. O.; Hillebrandt, W.; Ashall, C.; Mazzali, P. A.; Prentice, S. J., MNRAS, 460, 373S 07, 2016 - Contribution: Advising on how to deal with photometry and providing data for k-corrections of SN 2011fe. The Superluminous Transient ASASSN-15lh as a Tidal Disruption Event from a Kerr Black Hole, Leloudas, G.; Fraser, M.; Stone, N. C.; van Velzen, S.; Jonker, P. G.; Ar- cavi, I.; Fremling, C.; Maund, J. R.; Smartt, S. J.; Kruhler, T.; Miller-Jones, J. C. A.; Vreeswijk, P. M.; Gal-Yam, A.; Mazzali, P. A.; De Cia, A.; Howell, D. A.; Inserra, C.; Patat, F.; de Ugarte Postigo, A.; Yaron, O.; Ashall, C.; et al.,, arXiv:1609.02927, in press with Nature astronomy-Contribution: Providing data and taking observations. Cartier, R.; Sullivan, M.; Firth, R.; Pignata, G.; Mazzali, P.; Maguire, K.; Childress, M. J.; Arcavi, I.; Ashall, C.; et al., Early observations of the nearby type Ia supernova SN 2015F, In press with MNRAS, 464, 4476V, 2017- Contribution: Providing data, taking observations and giving advice on the science of spectral formation. SN 2009ip at late times - an interacting transient at +2 years, Fraser, Morgan; Kotak, Rubina; Pastorello, Andrea; Jerkstrand, Anders; Smartt, Stephen J.; Chen, Ting-Wan; Childress, Michael; Gilmore, Gerard; Inserra, Cosimo; Kankare, Erkki; Margheim, Steve; Mattila, Seppo; Valenti, Stefano; Ashall, Christopher; et al., MNRAS, 453, 3886F- 11, 2015 -Contribution: Providing data and taking observations. Supernova 2013fc in a circumnuclear ring of a luminous infrared galaxy: the big brother of SN 1998S,,Kangas, T.; Mattila, S.; Kankare, E.; Lundqvist, P.; Visnen, P.; Childress, M.; Pignata, G.; McCully, C.; Valenti, S.; Vink, J.; Pastorello, A.; Elias- 7 Rosa, N.; Fraser, M.; Gal-Yam, A.; Kotak, R.; Kotilainen, J. K.; Smartt, S. J.; Galbany, L.; Harmanen, J.; Howell, D. A.; Inserra, C.; Marion, G. H.; Quimby, R. M.; Silver- man, J. M.; Szalai, T.; Wheeler, J. C.; Ashall, C.; et al., MNRAS, 456, 323K- 02, 2016 -Contribution: Providing data and taking observations. PESSTO: survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Object, Smartt, S. J.; Valenti, S.; Fraser, M.; Inserra, C.; Young, D. R.; Sullivan, M.; Pastorello, A.; Benetti, S.; Gal-Yam, A.; Knapic, C.; Molinaro, M.; Smareglia, R.; Smith, K. W.; Taubenberger, S.; Yaron, O.; Anderson, J. P.; Ashall, C.; et al., , MNRAS, 579, 40S- 07, 2015 -Contribution: Providing com- ments on science. Contents Abstract 1 Acknowledgements 4 List of Publications 5 1 Introduction 23 1.1 SN classification . 24 1.2 SN Ia light curves . 27 1.3 SN Ia progenitors . 29 1.3.1 Single Degenerate scenario . 31 1.3.2 Double Degenerate (DD) scenario . 34 1.3.3 Triple system collision . 34 1.4 Nucleosynthesis . 35 1.5 SN Ia by host type . 36 1.6 SN Ia by sub types . 38 1.7 SN Ia spectra . 39 1.7.1 Photosperic phase . 39 1.7.2 Nebular phase . 41 1.8 SN Ia UV data . 43 8 CONTENTS 9 1.9 Outline of thesis . 44 2 Luminosity Distributions of SNe Ia 45 2.1 Preface . 45 2.2 Previous studies . 46 2.3 Data & Method . 48 2.4 Quality of LC spline fit . 54 2.5 Luminosity Distribution . 56 2.5.1 B and V luminosity distributions . 56 2.5.2 Width Luminosity Relation . 59 2.6 Correction for host galaxy extinction . 62 2.6.1 Luminosity Distribution . 65 2.6.2 Host galaxy extinction . 65 2.6.3 LD by host galaxy type . 68 2.6.4 WLR after extinction correction . 70 2.7 Full luminosity distribution . 72 2.8 SNe Ia from young and old stellar populations . 76 2.9 Discussion . 80 2.9.1 Errors and significance of results. 85 2.10 Conclusions . 86 3 Radiative transfer 89 3.1 Preface . 89 3.2 Radiative Transfer Theory . 89 3.3 Radiative Transfer in SN ejecta . 92 3.4 MC code .