京都大学 / 新制・課程博士 / 博士(理学) / 甲第25113号 / 理博第5020号 / 新制||理||1716(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 鶴 剛, 准教授 榎戸 輝揚, 教授 田島 治 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Advances in machine learning for visual recognition and ultra-low surface brightness imaging have made it possible to detect older and fainter historic supernova light echoes (SN LEs). We are particularly interested in the historic core-collapse SN (CCSN) Crab (SN 1054), as it is the only CCSN with records of direct-light observations in the last 1000 years. We have improved the SN LE machine-learning Python package ALED (Automated Light Echo Detection), created by Bhullar et al. 2021, by adding false positive masks as an additional input. ALED is visual recognition software that identifies and locates LEs in difference images. Before the invention of ALED, LE images had to be categorized by visual inspection, which was a very time-consuming task. Additionally, we have developed a method for manufacturing and augmenting LE training sets, which has previously not been applied to LEs. We manufactured Dragonfly Telephoto Array (DTA) LEs by extracting LEs from Canada-France-Hawaii Telescope difference images and overlaying them on DTA difference images. The DTA is a promising tool for LE detection because of its ability to observe ultra-low surface brightness structures. Additionally, we augmented the only existing DTA LE image by overlaying it on other DTA images. Both of these procedures provided options for further augmentation, such as changing the LE's brightness and width. We also created a process to mask the bright star difference artifacts in DTA images. These stars are typically mislabeled as LEs, and hence masking them makes LE identification simpler. We have created an effective DTA training set for ALED, which is prepared to search for LEs around the historic CCSN Crab (SN 1054), once more DTA images in that region are procured. / Thesis / Master of Science (MSc)

La première partie est une étude de l'évolution de la population des nuages HI en présence d'un milieu internuage de type coronal, entretenu par les explosions de supernova. La seconde partie concerne l'évolution d'un reste de supernova dans un milieu interstellaire hétérogene. La troisième partie propose un modèle dynamique de nébuleuse planétaire dont la morphologie et la dynamique doivent leur origine à une cavité centrale remplie de gaz coronal.

A two-dimensional hydrodynamic numerical model is extended and applied to simulate the interaction between stellar winds and the interstellar medium (ISM). In particular, the stellar wind evolution of O- and B-type stars is calculated. First, the evolution of a stellar wind into the ambient interstellar medium and also a more dense molecular cloud are considered for the case of no relative motion between the star and the interstellar medium. This interaction results in a cavity being blown into the ISM. Of importance in this work is the boundary radius (astropause) of the stellar wind and also the location where the outflow speed decreases from supersonic to subsonic speeds, called the termination shock. Different parameters like ISM density, outflow speed and mass-loss rate were varied to study the effect these have on the computed astropause (AP) and termination shock (TS) radii. The evolution of these structures is presented up to a simulation time of 1 My. However, stars are not stationary relative to the ISM, and the evolution of stellar winds into the interstellar medium including relative motion is also considered. It is shown that the positions of the TS and AP are dependent on the mass-loss rate and stellar wind outflow speed of the star and the interstellar medium density and relative speed. When these massive stars reach the end of their life, they end their life in a supernova explosion. The explosion results in a blast wave moving outward, called the forward shock (FS) and a reverse shock (RS) also forms which moves inward. Previous work done by Ferreira and de Jager (2008) to simulate supernova remnant (SNR) evolution, was only done for the case of evolution into the undisturbed ISM (no cavity). In this work, the evolution of SNR is simulated taking also into account the pre-existing cavity blown out by the stellar winds of these massive stars. The results of this study showed that the evolution of the SNR is definitely influenced by the presence of a stellar wind cavity even if the cavity is only a few pc in extent. / Thesis (MSc (Space Physics))--North-West University, Potchefstroom Campus, 2011.

A two-dimensional hydrodynamic numerical model is extended and applied to simulate the interaction between stellar winds and the interstellar medium (ISM). In particular, the stellar wind evolution of O- and B-type stars is calculated. First, the evolution of a stellar wind into the ambient interstellar medium and also a more dense molecular cloud are considered for the case of no relative motion between the star and the interstellar medium. This interaction results in a cavity being blown into the ISM. Of importance in this work is the boundary radius (astropause) of the stellar wind and also the location where the outflow speed decreases from supersonic to subsonic speeds, called the termination shock. Different parameters like ISM density, outflow speed and mass-loss rate were varied to study the effect these have on the computed astropause (AP) and termination shock (TS) radii. The evolution of these structures is presented up to a simulation time of 1 My. However, stars are not stationary relative to the ISM, and the evolution of stellar winds into the interstellar medium including relative motion is also considered. It is shown that the positions of the TS and AP are dependent on the mass-loss rate and stellar wind outflow speed of the star and the interstellar medium density and relative speed. When these massive stars reach the end of their life, they end their life in a supernova explosion. The explosion results in a blast wave moving outward, called the forward shock (FS) and a reverse shock (RS) also forms which moves inward. Previous work done by Ferreira and de Jager (2008) to simulate supernova remnant (SNR) evolution, was only done for the case of evolution into the undisturbed ISM (no cavity). In this work, the evolution of SNR is simulated taking also into account the pre-existing cavity blown out by the stellar winds of these massive stars. The results of this study showed that the evolution of the SNR is definitely influenced by the presence of a stellar wind cavity even if the cavity is only a few pc in extent. / Thesis (MSc (Space Physics))--North-West University, Potchefstroom Campus, 2011.

Vers la fin des années 1990, l’utilisation des supernovae de type Ia (SNe Ia) comme indicateurs de distance a permis de mettre en évidence l’expansion accélérée de l’univers. Depuis lors, des campagnes d’observations de grandes envergures ont permis d’augmenter de façon significative le nombre de SNe Ia observées, mais les incertitudes systématiques liées à la qualité des échantillons de SNe Ia proches restent un facteur limitant sur la précision des mesures actuelles. C’est dans le but de réduire ces incertitudes que le projet the Nearby Supernova Factory (SNfactory), à l’aide d’un instrument spectro-photométrique dédié à l’observation des SNe Ia (the Supernova Integral Field Spectrograph), a collecté depuis 2004 plus de 3000 spectres de près de 200 SNe Ia proches. Une des limitations actuelles de leur utilisation, outre les aspects liés aux problèmes d’inter-calibration entre les différentes expériences, est celle du mélange des différentes composantes de leurs variabilités lors de la standardisation empirique de leur module de distance. Une meilleure séparation de ces composantes, ainsi que la découverte de nouveaux indicateurs de distance, font partie des améliorations que peut apporter un échantillon spectral de SNe Ia proches tel que celui de la collaboration SNfactory. Cette thèse de doctorat, effectuée à l’Institut de Physique Nucléaire de Lyon et au Lawrence Berkeley National Laboratory, s’inscrit directement dans cette problématique, en se concentrant sur la mesure d’indicateurs spectraux sur l’échantillon spectral de la collaboration Snfactory. Le plan de cette thèse est le suivant : La première partie présente le contexte scientifique ainsi que l’échantillon de SNe Ia de la collaboration SNfactory utilisé dans les analyses. La deuxième partie se concentre sur la méthode de mesure d’indicateurs spectraux appliquée à l’échantillon spectrale présenté, ainsi que sur une étude de leur sensibilité à l’extinction par le milieu interstellaire. La troisième partie est une étude des corrélations des indicateurs spectraux et de leur utilisation pour la standardisation des Sne Ia. Dans la dernière partie, une utilisation de ces indicateurs spectraux pour la détermination d’une loi d’extinction moyenne est présentée / One of the current limitations of type Ia supernovae used as distance indicators is themixing of their different sources of variabilitiy during the empirical standardization of their distance modulus. Using the nearby SNe Ia spectral sample observed by the Nearby Supernovae Collaboration with the instrument SNIFS (Supernovae Intergral Field Sperctrograph), this thesis mainly focuses on this problematic using spectral indicators measurements. The first part of the thesis presents the scientific context as well as the sample used in the analysis. The second part focus on the spectral indicators measurement and their properties in the presence of interstellar dust extinction. The third part is a study of spectral indicators correlations and their use as standardization parameters. In the last part, we use these spectral indicators to construct a mean extinction law for type Ia supernovae

In dieser Diplomarbeit wurde das astrophysikalisch interessante Resonanztriplett der Reaktion 40Ca(α,γ)44Ti bei 4,5MeV untersucht. Am 3-MV-Tandetron des Helmholtz-Zentrums Dresden-Rossendorf wurden dafür die Energien von Protonen- und -Strahlen kalibriert, Anregungsfunktionen im Energiebereich der drei Resonanzen aufgenommen, vier CaOTargets aktiviert und deren Struktur mittels der Reaktion 40Ca(p,γ)41Sc überprüft. Im Felsenkeller-Niederniveaumesslabor wurde anschließend die Aktivität der Proben gemessen. Schließlich konnte die Summe der Resonanzstärken bei 4497 und 4510 keV -Energie im Laborsystem zu (12;8 2;3) eV und die Summe der Resonanzstärken des gesamten Tripletts, d.h. zusätzlich bei 4523 keV, zu (12;0 2;0) eV bestimmt werden. Bei der ersten Resonanzstärke konnte die Unsicherheit im Vergleich zur Literatur von 19% auf 18% verbessert werden. Außerdem bieten die Daten der vorliegenden Arbeit die Grundlage, zukünftig die Unsicherheiten noch erheblich weiter zu reduzieren. / In this thesis the astrophysically interesting resonance triplet of the 40Ca(α ,γ)44Ti reaction at 4.5MeV has been studied. For this purpose energies of proton and beams provided by 3MVTandetron at Helmholtz-Zentrum Dresden-Rossendorf have been calibrated. Excitation functions of energy regions near the resonances and in-beam spectra of four different targets have been measured. The 40Ca(p,γ)41Sc reaction has been used to scan the structure of the activated targets. Afterwards their activity has been measured in the underground laboratory Felsenkeller Dresden. Hence the sum of resonance strengths at laboratory energies of 4497 and 4510 keV of (12:8 2:3) eV has been determined as well as the sum of the total triplet strength, including 4523 keV, of (12:0 2:0) eV. In the case of the first resonance, the uncertainty was decreased from 19% to 18 %. Furthermore the results of this work establish a basis for reaching much lower uncertainties in the future.

Abbildende Cherenkov-Teleskope haben in den letzten Jahren eine groẞe Anzahl neuer Gammastrahlungsquellen im Bereich sehr hoher Energien (VHE, very high energy, E>100 GeV) entdeckt. Diese Studie behandelt Vertreter von drei unterschiedlichen Klassen von galaktischen Gammastrahlungsquellen: die Supernova-Überreste G1.9+0.3 und G330.2+1.0, den Pulsarwind-Nebel HESS J1303-631 und das Binärsystem PSR B1259-63/LS 2883. Für alle Objekte werden die Analyse der H.E.S.S.-Daten und die Modellierung der Emission unter Einbeziehung von Daten aus anderen Wellenlängenbereichen dargestellt. / Recently, imaging atmospheric Cherenkov telescopes have discovered numerous new sources representing various source classes in the very high energy (VHE; E>100 GeV) sky. This work presents studies of representatives of three types of Galactic VHE emitters: the Supernova remnants G1.9+0.3 and G330.2+1.0, the pulsar wind nebula HESS J1303-631 and the binary system PSR B1259-63/LS 2883. The analysis of the H.E.S.S. data and the broadband emission modeling are presented.

I present a comprehensive investigation of fast stars in the Milky Way, from brisk disc stars to stars escaping the Galaxy. My thesis is that fast stars are the smoking guns of extreme stellar collisions and explosions, and so can act as an intermediary to studying these theoretically-unconquered astrophysical processes. In Chapter 1 I give a history of fast stars, address what it means for a star to be fast, and describe the processes that accelerate stars. I concisely summarise the Gaia mission, whose recent data releases heavily influenced this thesis. Supernovae in binary systems can fling away the companion; if a runaway companion can be associated with a supernova remnant, then together they reveal the evolution that led to the supernova. However, these associations are difficult to establish. In Ch. 2, I develop a sophisticated Bayesian methodology to search the nearest ten remnants for a companion, by combining data from Gaia DR1 with a 3D dust-map and binary population synthesis. With Gaia DR2, I will identify companions of tens of supernova remnants and thus open a new window to studying late-stage stellar evolution. It is unknown why 17% of B stars are spinning near break-up; these stars are termed Be stars because of emission lines from their ejected material. Their rapid spin could be due to mass transfer, but in Ch. 3 I show this would create runaway Be stars. I demonstrate using a hierarchical Bayesian model that these exist in sufficient numbers, and thus that all Be stars may arise from mass transfer. The stars escaping the Milky Way are termed hypervelocity stars. In Ch. 4, I overturn the consensus that the hypervelocity stars originated in the Galactic centre by showing that a Large Magellanic Cloud (LMC) origin better explains their distribution on the sky. In Ch. 5 I present three ground-breaking hypervelocity results with Gaia DR2: 1) only 41 of the 524 hypervelocity star candidates are truly escaping, 2) at least one of the hypervelocity stars originates in the LMC, and 3) the discovery of three hypervelocity white dwarf runaways from thermonuclear supernovae.

Supernovae (SNe) and more specifically Core-Collapsed SNe (CC SNe) are signatures of on-going star formation (SF), and higher star formation rates. In this project, we perform a study of all SNe ever discovered inside a specific type of galaxy: a type-1 Active Galactic Nucleus (AGN1). We calculate the SN detection fraction for CC SNe and thermonuclear SNe in AGN1. In AGN1, inclination of the host galaxy and the radial distance of the SN to the center of the galaxy are displayed. As a second goal, we gather all SNe from the OpenSN catalogue found close to an AGN1, classify them and compare them with the full sample of OpenSN catalogue host galaxies. Results:We found and calculated the SN detection fraction of AGN1s. We found 16 SNe exploding in 13 different AGN1 host galaxies. The CC/Ia SN ratio is ~ 0.78. Comparing by similar morphology, the AGN1-host galaxies with all the host galaxies from OpenSN, we see that the detection fractions are higher in spiral AGN1 hosts than in normal spiral galaxies, but the difference is not significant (~ 0.4\sigma) to be considered.