Dissertations / Theses on the topic 'Supernova spectroscopy'
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Folatelli, Gastón. "Type Ia Supernova Cosmology : Quantitative Spectral Analysis." Doctoral thesis, Stockholm University, Department of Physics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-80.
Full textType Ia supernovae have been successfully used as standardized candles to study the expansion history of the Universe. In the past few years, these studies led to the exciting result of an accelerated expansion caused by the repelling action of some sort of dark energy. This result has been confirmed by measurements of cosmic microwave background radiation, the large-scale structure, and the dynamics of galaxy clusters. The combination of all these experiments points to a “concordance model” of the Universe with flat large-scale geometry and a dominant component of dark energy.
However, there are several points related to supernova measurements which need careful analysis in order to doubtlessly establish the validity of the concordance model. As the amount and quality of data increases, the need of controlling possible systematic effects which may bias the results becomes crucial. Also important is the improvement of our knowledge of the physics of supernovae events to assure and possibly refine their calibration as standardized candle.
This thesis addresses some of those issues through the quantitative analysis of supernova spectra. The stress is put on a careful treatment of the data and on the definition of spectral measurement methods. The comparison of measurements for a large set of spectra from nearby supernovae is used to study the homogeneity and to search for spectral parameters which may further refine the calibration of the standardized candle. One such parameter is found to reduce the dispersion in the distance estimation of a sample of supernovae to below 6%, a precision which is comparable with the current lightcurve-based calibration, and is obtained in an independent manner. Finally, the comparison of spectral measurements from nearby and distant objects is used to test the possibility of evolution with cosmic time of the intrinsic brightness of type Ia supernovae.
Kasai, Eli Kunwiji. "SALT spectroscopy and classification of supernova spectra using Bayesian techniques." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/27283.
Full textRigault, Mickaël. "Analyses des propriétés locales des galaxies hôtes des Supernovae de type Ia dans la collaboration The Nearby Supernova Factory." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10145/document.
Full textType Ia supernovae (SNe Ia) are powerful cosmological distance indicators. They were key tools for the discovery of the accelerating expansion of the Universe and today they remain the strongest demonstrated technique for measuring the dark-energy equation of state. However, a major issue remains: despite decades of study, their progenitors are as yet undetermined. Notably, we still ignore the influence of the redshift-evolution of stellar properties on the absolute luminosity of the SNe Ia and therefore on the fitted cosmological parameters. Recent studies have highlighted potential biases correlated with the global properties of their host galaxies, large enough to induce systematic errors into cosmological measurements if not properly treated. However, those studies analyse hosts of Type Ia supernovae globally thus neglecting the known stellar and gas property variations across galaxies. ! In this thesis, I show how integral field spectroscopy data from the Nearby Supernova Factory allow the study of the local environment of the SNe Ia (~kpc). In the first part of this document, I introduce the physical principals and the scientific context of this work. In a second part, I start by detailing the technical extraction tools developed in order to extract the local host properties. Then, I show how one could measure the star formation activity in the SN vicinity from those data. I focus the analysis on this star formation activity and notably I show how the SNe Ia properties -- particularly their standardised Hubble residuals -- depend on the local host environment, which corresponds to a significant cosmological bias. I finish this second part by introducing a simple model based on the known evolution of the galactic star formation activity. This model enables me to estimate the potential influence of the aforementioned environmental bias on cosmology. I also show that this model can be tested using public data and a first analyses tend to confirm our hypotheses. Those results have been published in Astronomy & Astrophysics (Rigault et al. 2013). The third and last part of the document introduces new approaches and future work perspectives. ! In this thesis, I have highlighted significant environmental biases in SNe Ia properties, thanks to the local approach. However, those biases are less an issue for the cosmological analyses using Type Ia supernovae than a new opportunity to improve them as cosmological probes. ! This Document is written in French. The figures are in English
Hayashi, Ichizou. "Systematic X-ray Spectroscopy of Supernova Remnants in the Magellanic Clouds." 京都大学 (Kyoto University), 1997. http://hdl.handle.net/2433/202434.
Full textGalbany, i. Gonzàlez Lluís. "Supernova studies in the SDSS-II/SNe Survey: Spectroscopy of the peculiar SN 2007qd, and photometric properties of Type-Ia supernovae as a function of the distance to the host galaxy." Doctoral thesis, Universitat Autònoma de Barcelona, 2011. http://hdl.handle.net/10803/83974.
Full textEsta tesis engloba el trabajo realizado durante los últimos cuatro años como estudiante de doctorado en el Institut de Física d’Altes Energies (IFAE), enmarcardo en la colabaración Sloan Digital Sky Survey II Supernova (SDSS-II/SNe) Survey. En el primer capítulo (§1) se introducen los principales conceptos del Modelo Estándar de Cosmología, presentando sus orígenes, las propiedades de sus contenidos, y las medidas de distancia y brillo. También se reconstruyen la historia del universo desde el Big Bang y se resumen algunos de los descubrimientos más excitantes que han confirmado las predicciones del Modelo Estándar. Seguidamente (§2), se da una explicación detallada de las supernovas (SNe), incluyendo el mecanismo físico que da lugar a las explosiones, las diferencias entre los diferentes tipos, y su clasificación espectral. También se describen las propiedades fotomètricas y espectroscópicas de las supernovas de tipo Ia. A continuación, se resumen las medidas del ritmo de explosión, las propiedades de las galaxias donde residen las supernovas, y su uso en Cosmología a través del diagrama de Hubble. En el siguiente capítulo, (§3) se describe SDSS-II/SNe Survey, una extensión de tres años (2005-2007) del proyecto Sloan (SDSS) que ha detectado y medido curvas de luz para centenares de supernovas a través de escanear el cielo en repetidas ocasiones. Como parte del seguimiento espectroscópico de las supernova de SDSS-II/SNe, contribuímos obteniendo 23 espectros de supernovas durante 4 noches de Octubre y Noviembre (5-6 Oct. y 4-5 Nov.) del 2007, utilizando el Telescopio Nazionale Galileo (TNG) situado en el Observatorio del Roque de Los Muchachos (ORM) en La Palma. En el capítulo §4 se describe toda la reducción de datos, desde la adquisición de las imágenes hasta los espectros calibrados en flujo y longitud de onda. Siguiendo la reducción de los espectros, en el capítulo §5, se describe una de las supernovas de tipo Ia menos luminosa jamàs conocida, la peculiar 2007qd, para la cual medimos el primer espectro. Las propiedades observadas de la 2007qd la sitúan en la subclase llamada 2002cx, como miembro intermedio entre las supernovas 2002cx y 2008ha, enlazándolas. Se presentan las observaciones espectroscópicas y fotométricas de la supernova 2007qd y se comparan su propiedades con un conjunto de otras supernovas. Éste análisis fue publicado en McClelland et al. (2010). En el capítulo §6, se utilizan las supernovas Ia descubiertas por SDSS-II/SNe Survey durante los tres años de actividad, para buscar dependencias entre las propiedades fotométricas de las supernovas Ia y la proyección de la distancia hasta el centro de la galaxia donde residen, utilizando la distancia como aproximación a las propiedades locales de las galaxias (ritmo de creación de estrellas, metalicidad local, etc.). Encontramos que el exceso de color de las supernovas, parametrizado por AV en MLCS2k2 y por c en SALT2 decrece con la distancia, en particular para las galaxias espirales. Además, y con menos significancia, también se encuentra que la amplitud de la curva de luz, obtenida con MLCS2k2, está correlacionada con la separación entre la supernova y el centro de la galaxia para las galaxias elípticas, así las supernovas con curvas de luz más estrechas, y menos luminosas, se observan a más distancia del centro galactico. Este análisis fue presentado en la conferencia Supernovae and their Host Galaxies que tuvo lugar en Junio del 2011 en Sydney, y serà publicado en Galbany et al. (2011). Finalmente, en §7, se resume y se presentan las conclusiones de esta tesis.
This thesis comprises the work I have been doing during the last four years at Institut de Física d’Altes Energies (IFAE) as a PhD student, and has to be understood within the context of the Sloan Digital Sky Survey II Supernova (SDSS-II/SNe) survey. The content of this thesis is ordered as follows. In the next Chapter (§1) I introduce the main concepts of the Standard Model of Cosmology, presenting the origins, the properties of its contents, and the distance and the brightness measurements. I also reconstruct the history of universe since the Big Bang and summarize some of the most exciting discoveries that have confirmed the Standard Model predictions. In §2, a detailed explanation of supernovae (SNe) is given, including the physical mechanism that accounts for their explosions, the differences among the several types of SNe, and their spectral classification. We also describe the spectroscopic and photometric properties of Type-Ia SNe. After that, we review the SNe rate of the explosion measurements, the properties of their host galaxies, and their use in Cosmology through the Hubble diagram. After that, in §3, I describe the SDSS-II/SNe survey, a three-year (2005-2007) extension of SDSS of which I am an external collaborator, which has detected and measured light-curves for several hundred supernovae through repeat scans of the sky. As a part of the spectroscopic follow-up of the SDSS-II/SNe candidates, we contributed to the project taking spectra of 23 SNe during four nights in October and November (5-6 Oct. and 4-5 Nov.) of 2007 using the Telescopio Nazionale Galileo (TNG) located at the Observatorio del Roque de Los Muchachos (ORM) in La Palma. In §4, the whole reduction procedure, from the acquisition of the raw data by the telescope camera to the final flux-calibrated spectra, is described. Following the spectra reduction, in §5, I describe one of the most subluminous type-Ia events known, the peculiar 2007qd supernova, for which we took the first spectrum. The observed properties of 2007qd place it in the 2002cx subclass of supernovae, specifically as a member intermediate to 2002cx and 2008ha, linking these objects. We present the photometric and spectroscopic observations of 2007qd and compare its unique properties with a range of other SNe. This work was compiled and published in McClelland et al. (2010). Then, in §6, the three-year sample of Type Ia supernovae (SNe Ia) discovered by the SDSS-II/SNe Survey is used to look for dependencies between photometric SN Ia properties and the projected distance to the host galaxy center, using the distance as a proxy for local galaxy properties (local star-formation rate, local metallicity, etc.). We find that the excess color of the SN, parametrized by AV in MLCS2k2 and by c in SALT2 decreases with the projected distance, in particular for spiral galaxies. At a lower significance we find that the light-curve width, as obtained from MLCS2k2 , is correlated with the SN-galaxy separation for elliptical hosts, so that SNe Ia with narrower light-curves, hence dimmer, are more commonly observed at large distances from the host galaxy core. This analysis was presented in the Supernovae and their Host Galaxies conference which was held at Sydney, Australia in June 2011, and will be published in Galbany et al. (2011). Finally, in §7 we give a summary and the conclusions of this thesis.
Cellier-Holzem, Flora. "Spectroscopie des supernovae de type Ia des expériences SuperNova Legacy Survey et Nearby SuperNova Factory pour la cosmologie." Paris 6, 2013. http://www.theses.fr/2013PA066568.
Full textType Ia supernovae (SNe Ia) are a powerful tool in cosmology today to study the acceleration of the universal expansion. Using as standardisable candles, they allow us to constrain the dark energy equation of state via a Hubble diagram. The spectroscopy is essential to build this diagram, on the one hand to secure the type of SNe Ia and estimate the redhsift, and on the other hand for a better knowledge of their physical properties to reduce the systematic uncertainties which limit the use of SNe Ia for cosmological works. In this context, I build a new sample of SN Ia spectra measured by the Very Large Telescope (VLT) for the SuperNova Legacy Survey (SNLS) experiment. These SN Ia data complete the existing sample to constitute the final VLT spectroscopic dataset of the SNLS. In addition to the inclusion in the Hubble diagram for cosmological analysis, this spectroscopic sample can be used to test if SNe Ia properties evolve with the redshift. I investigate this fundamental question for cosmology using the new VLT spectra sample of distant SNe Ia and the nearby object of the Nearby SuperNova Factory (SNF) experiment. These two samples are also a rich source of physical information for a better knowledge of SNe Ia and a better standardisation. For this purpose, I compare these data with various SNe Ia formation models to identify discriminant spectral area or parameters in order to constrain and improve the models to reproduce the observations and the SNe Ia variability
Spyromilio, Jason. "Infrared spectroscopy of supernovae." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47669.
Full textFasia, Alexandra. "Spectroscopic study of core-collapse supernovae." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313777.
Full textRigault, Mickaël. "Analyses des propriétés locales des galaxies hôtes des Supernovae de type Ia dans la collaboration The Nearby Supernova Factory." Phd thesis, Université Claude Bernard - Lyon I, 2013. http://tel.archives-ouvertes.fr/tel-00905574.
Full textBazin, Gurvan. "Analyse différée des données du SuperNova Legacy Survey." Paris 7, 2008. http://www.theses.fr/2008PA077135.
Full textThe SuperNova Legacy Survey (SNLS) experiment observed type la supemovae (SNeHa) during 5 years. Its aim is the contraint cosmological parameters. The online reduction pipeline is based on spectroscopic identification for each supernova. Systematically using spectroscopy requires a sufficient signal to noise level. Thus, it could lead to selection biases and would not be possible for future surveys The PhD thesis report a complementary method for data reduction based on a completely photometric selection. This analysis, more efficient to select faint events, approximately double the SNeHa sample of the SNLS. This method show a clear bias in the spectroscopic selection. Brighter SNeHa are systematically selected beyond a redshift of 0. 7. On the other hand, no important impact on cosmology was found. So, corrections on intrinsic variability of SNeHa luminosity are robust. In addition, this work is a first step to study the feasibility of such a purely photometric analysis for cosmology. This is a promising method for future projects
Sainton, Grégory. "Spectroscopie des supernovæ à grand décalage vers le rouge." Phd thesis, Université Claude Bernard - Lyon I, 2004. http://tel.archives-ouvertes.fr/tel-00106153.
Full textdécalage vers le rouge ("évolution"). Dans le cadre des collaborations Supernova Cosmology Project (SCP) et SuperNova Legacy Survey (SNLS), dont l'objectif scientique commun est l'étude de l'énergie noire à l'aide de supernovæ de type Ia à grand décalage vers le rouge, une part importante du travail de thèse est consacrée à la réduction des données spectrales,
étape nécessaire pour obtenir le spectre physiquement exploitable à partir de données observées. La réduction de l'ensemble des spectres SCP issus du spectrographe à échellettes Keck-ESI a permis d'obtenir des supernovæ de type Ia parmi les plus lointaines jamais observées. Dans l'expérience SNLS, l'identication spectroscopique est essentiellement réalisée avec le spectrographe longue fente FORS1 monté au foyer du VLT UT1. Pour le SNLS, il s'agit de réduire et d'identier une dizaine de spectres par lunaison pendant 5 ans. Dans le cadre de cette thèse, un logiciel d'identication en temps réel de SNIa a été developpé, il permet d'établir le type, le décalage vers le rouge et l'âge du candidat quasi automatiquement. Il évalue aussi la contamination
de la galaxie hôte (dont on peut aussi estimer la morphologie) dans le spectre. Le logiciel a été testé sur un échantillon de spectres analysés en détail.
Par ailleurs, pour certains d'entre eux, on a mesuré la vitesse du CaH&K (3945.12Å) dans la photosphère puis
on a comparé les résultats avec les mêmes mesures réalisées sur un lot de spectres proches. Ce résultat a permis de conrmer l'hypothèse de standardité des SNIa à grand décalage vers le rouge. C'est une hypothèse fondamentale pour mesurer les paramètres cosmologiques avec les supernovæ de type Ia.
Williamson, Jacob. "SN2005da: A Spectroscopic and Photometric Analysis of a Peculiar Type Ic Supernova." Ohio University Art and Sciences Honors Theses / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ouashonors1493239779235968.
Full textBronder, T. Justin. "A quantitative spectroscopic comparision of distant and nearby type Ia supernovae." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437173.
Full textNordin, Jakob. "Spectral Properties of Type Ia Supernovae and Implications for Cosmology." Doctoral thesis, Stockholms universitet, Fysikum, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-56785.
Full textAt the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Accepted.
Le, Du Jérémy. "Utilisation de la spectroscopie pour la standardisation des supernovae de type Ia." Aix-Marseille 2, 2008. http://theses.univ-amu.fr.lama.univ-amu.fr/2008AIX22073.pdf.
Full textWe present in this thesis an analysis of the standardisation of Type Ia supernovae (SNela) using distant supernovae (0. 2
Decourchelle, Anne. "Le gaz chaud dans les restes de supernova : hydrodynamique, etat d'ionisation, spectroscopie x et optique." Paris 7, 1994. http://www.theses.fr/1994PA077226.
Full textLi, Kwan-lok, and 李君樂. "Study of x-ray supernovae and supersoft/quasisoft x-ray sources with an automated source search program." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46084125.
Full textDepagne, Éric. "Abondance des éléments plus légers que le zinc dans les premières étoiles galactiques : implications sur la nature des premières supernovae." Paris 6, 2003. https://tel.archives-ouvertes.fr/tel-00165388.
Full textDuring my Ph. D. I have analyzed 33 extremely metal-deficient galactic halo stars (stars having less than 500 times less metals than the Sun) observed at the VLT, using the high resolution spectrograph UVES. These stars are relics from the very first ages of our Galaxy, and thud provide useful constraints on both the formation and on the evolution models of our Galaxy. I determined the abundances for 17 elements from carbon to zinc with an unprecedented accuracy, including the key elements oxygen and zinc, to understand which kind of supernova had enriched the interstellar medium during the early times of the Galaxy. I have shown in this work that we could explain the observed abundance ratio without including very massive supernova (stars whose mass is greater then M Sun). In addition, the abundance trends are compared with Galactic chemical evolution models. As the study is based on very metal poor stars that are supposed to be born during the first ages of our Galaxy, my work brings strong new observational constraints to these models
Filiol, Mélanie. "Etude de l'environnement des supernovae de type IA : implications sur la mesure des paramètres cosmologiques." Aix-Marseille 1, 2006. http://www.theses.fr/2006AIX11056.
Full textThis thesis was done within the context of the Franco-Canadian collaboration SuperNova Legacy Survey. This thesis was to study the nature of the hosts galaxies of the type Ia supernovae to estimate their influence on the properties of the type Ia supernovae and the determination of the cosmological parameters. For that, the nature of the host was given thanks to three methods of identification (spectroscopic, photometric and morphological). I considered two classes of galaxies for the continuation of my study: early galaxies and late galaxies. After having identified the type of hosts galaxies of the type Ia supernovae, so I studied the influence which could have those on the photometric properties of the type Ia supernovae. Then, I built a Hubble diagram of the type Ia supernovae as a function of nature of the host galaxy to be able to estimate the influence of the host galaxy on the determination of the cosmological parameters
Ballet, Jean. "Le gaz chaud dans le milieu interstellaire, des restes de supernovae a la phase coronale diffuse." Paris 7, 1988. http://www.theses.fr/1988PA077174.
Full textCrouzet, Pierre-Elie. "Etude des propriétés d'un détecteur infrarouge H2RG pour l'optimisation d'un spectrographe embarqué sur le satellite SNAP/JDEM." Aix-Marseille 2, 2009. http://theses.univ-amu.fr.lama.univ-amu.fr/2009AIX22079.pdf.
Full textThe SNAP (SuperNovae Acceleration Probe) mission is designed to measure very precisely the cosmological parameters and to determine the nature of the Dark energy. The mission is based on the measurement of some thousands supernovae of type Ia up a redshift of z=1. 7 and on weak gravitational lensing measurements of more than one thousand square degrees of the sky. The SNAP experiment consists in a 2-meter telescope with a one square-degree imager and an integral field spectrograph. We present in this thesis study on hybrid detector H2RG (produce by Teledyne) to improve performances of the SNAP spectrograph. The H2RG 40 detector was characterized and used in the spectrograph demonstrator. The way of sampling has been optimized to decrease the readnoise and detect cosmic ray and the impact on the spectrograph performances have been evaluated
Rahal, Youcef Rabah. "Recherche de microlentilles gravitationnelles vers les bras spiraux de la Galaxie et spectroscopie de supernovae dans EROS II." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2003. http://tel.archives-ouvertes.fr/tel-00004301.
Full textDans la seconde partie, nous présentons l'analyse des données spectroscopiques, collectées durant une campagne internationale de recherche de supernovae Ia menée au printemps 1999, à laquelle EROS II a participé. Une vingtaine de supernovae Ia ont été découvertes puis suivies pendant cette campagne. Nous avons réduit les données spectroscopiques les concernant, qui consistent en une centaine de spectres au total. Nous avons developpé pour celà un programme original permettant de séparer le flux de la supernovae de celui de sa galaxie hôte. Nous avons ensuite procédé à une étude de stan dardisations sur un lot regroupant des objets de la campagne 1999 et des objets découverts antérieuement. L'étude sur ces 17 supernovae Ia a permis de confirmer l'interêt des spectres pour la standardis ation. Elle montre en particulier que la standardisation à partir de spectres est aussi efficace que celle basée sur le taux de décroissance des courbes de lumière.
Mattila, Seppo Kalevi. "Supernovae as probes of their host galaxies and circumstellar environments : search strategies in nuclear starbursts and spectroscopy of the SN 1987A CSM." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396416.
Full textBaumont, Sylvain. "Analyse des spectres VLT pour l'expérience SNLS : Qualification de transients cosmologiques." Phd thesis, Université Paris-Diderot - Paris VII, 2007. http://tel.archives-ouvertes.fr/tel-00196934.
Full textLa standardisation nécessaire à l'utilisation des SN-Ia comme indicateurs de distance repose sur la mesure précise des courbes de lumière dans 4 filtres (g', r', i' et z' pour MégaCam au CFHT). La mesure de la vitesse de récession, via le décalage vers le rouge, ainsi que la validation du transient comme étant bien une SN-Ia procèdent du suivi spectroscopique.
L'instrument FORS1 du Very Large Telescope de l'ESO assure l'essentiel de ce suivi. L'imposant lot de données, la fréquente faiblesse du signal et la volonté de tester des algorithmes alternatifs de calibration des images et d'extraction des spectres m'ont amené à développer une chaîne de réduction indépendante et automatisée. Cet ouvrage présente une méthode compréhensive, d'approche statistique, pour une extraction systématisée du spectre du transient et de celui de sa galaxie hôte lorsque ces sources sont effectivement résolues.
Ceci par le developpement logiciel en C++ et en Python, en interaction avec les produits du suivi photométrique : les images profondes des champs et les courbes de lumière des transients. La classification des transients reste subjective, mais est éclairée par l'ajustement simultané des courbes de lumières et du spectre par SALT2, un modèle empirique de SN-Ia (J.Guy 2007).
117 SN-Ia certaines ou probables (55% puis 73% des observations des deux premières années) sont ainsi identifiées.
Gilardy, Gwenaelle. "Measuring the 7Li(a ; g)11B reaction rate at temperatures relevant for the n-process." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0398/document.
Full textThe study of (a,g) reactions of astrophysical interest is quite vast. These reactions play an important role in the quiescent Helium burning phase of stars, in big bang nucleosynthesis and in most explosive stellar scenarios. The studies of (a,g) reactions involving stable beams are performed in various ways. I have been concentrating on two of them. The first one is studying these reactions in direct kinematics by detecting the produced gamma rays. This is what I did during my thesis to measure the cross section of 7Li(a,g)11B. It has been studied throughout the years for several purposes in nuclear astrophysics. For example, it was postulated it could solve the big bang nucleosynthesis Lithium problem. Nowadays, it is clear it does not.However, this reaction plays a role in the production of Boron during type Ic Supernovae. Another way to study (a,g) reactions is to use inverse kinematics. The idea is to send a heavy element beam on a Helium target. This kind of kinematics allows for the detection, with good efficiency, of the heavy recoil product if the beam that did not interact in the target is properly separated. Recoil mass separators, like St. George, are built for this purpose. St. George will be involved in measuring cross sections of reaction important for the s-process like 16O(a,g)20Ne
Meyer, Anne. "Étude expérimentale des réactions ¹³N(a,p)¹⁶O et ³⁰P(p,g)³¹S, et impact sur les abondances isotopiques extrêmes en ¹³C, ¹⁵N et ³⁰Si dans les grains pré-solaires." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS013.
Full textPrimitive meteorites contain several types of dust grains that condensed in different stellar environments and survived destruction in the early Solar System. The stellar sources where these presolar grains come from are identified through comparisons between measurements of isotopic abundances and predictions by stellar models. In this manuscript is presented a detailed analysis of two experiments performed at the ALTO facility, using the split-pole magnetic spectrometer, aiming at reducing the nuclear uncertainties associated to two reactions which rate uncertainty affects the synthesis of isotopes used to identify putative novae grains. These grains are characterised by extremely high ¹³C, ¹⁵N and ³⁰Si isotopic abundances, but isotopic signatures found in a few grains indicate also a possible core-collapse supernovae (CCSN) origin. We first study the impact of the ¹³N(a,p)¹⁶O reaction rate uncertainty on ¹³C abundances predicted by recent CCSN models. We perform a re-evaluation of this reaction rate using a Monte Carlo approach to obtain meaningful statistical uncertainties. Alpha partial widths of states in the ¹⁷F compound nucleus are determined using the spectroscopic informations of the analog states in the ¹⁷O mirror nucleus that were measured using the ¹³C(7Li,t)¹⁷O alpha-transfer reaction. We then study the ³⁰P(p,g)³¹S reaction, which is one of the few remaining reactions which rate uncertainty has a strong impact on classical novae model predictions, in particular for ³⁰Si abundances. To reduce the nuclear uncertainties associated to this reaction, we studied the ³¹P(³He,t)³¹S reaction. Triton and proton decays from the populated states in ³¹S were detected simultaneously using the spectrometer and silicon strip detectors. The study of the angular correlations of proton decays is presented and branching ratios are extracted
Giraud, Simon. "Mesures de masse autour du 78Ni et nouveau traitement de l'équilibre statistique nucléaire pour l'étude des supernovae à effondrement de coeur." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC219.
Full textThe thesis sets itself in the framework of the study of core-collapse supernovae (CCSN). First, the modeling of the composition of the core of a massive star during its collapse has been investigated. To this aim, we have built a new treatment of the nuclear statistical equilibrium starting from a single-nucleus approximation equation of state (Lattimer and Swesty, LS). This allows a more realistic description of the nuclear distribution inside the core and, more specifically, to quantify the role of the nuclear masses. The distributions obtained with the original mass functional (LS) and those obtained with HFB-24 and DZ10 mass models have been compared for several thermodynamic conditions of a typical CCSN trajectory. The differences in the composition could lead up to ∼25% deviations in the electron-capture rate, thus showing the need to identify a proper mass model to use in CCSN simulations. Therefore, we performed high precision mass measurements in the nuclear mass region of interest, via a double Penning trap at the IGISOL facility (Jyväskylä, Finland). Five new mass excess were determined for the following nuclei : 69m,70Co, 74,75Ni and 76mCu. The precision has been improved for five others : 67Fe, 69Co, 76,78Cu and 79mZn. Finally, we have confirmed the values obtained by recent studies for 77Cu and 79Zn. The experimental values of the nuclear gaps for Z=28 and N=50 have been compared with the results predicted by DZ10 and HFB-24. The latter model better reproduces the evolution of these gaps. Therefore, HFB-24 was used in our new statistical treatment, that we implemented in an existing CCSN hydrodynamical simulation. We have observed a moderated impact of the mass model on the composition of the collapsing core. Moreover, we found that the differences in composition have small effect on the collapse dynamics, which appears to be more sensitive to the electron-capture model. Further studies should thus focus on this parameter
Martin, Pierrick. "La vie et la mort des étoiles massives révélées par l'observation des raies gamma nucléaires grâce au spectromètre INTEGRAL/SPI." Phd thesis, Université Paul Sabatier - Toulouse III, 2008. http://tel.archives-ouvertes.fr/tel-00358223.
Full textDans un premier temps, nous nous concentrons sur l'émission de décroissance du 44Ti présent dans le vestige de supernova Cassiopée A. Le but de cette étude est d'obtenir, par une analyse spectrale du signal, une information sur la cinématique de l'ejecta de Cassiopée A. Une telle donnée pourrait alors nous renseigner sur le mécanisme incertain par lequel l'effondrement gravitationnel d'une étoile massive en fin de vie aboutit à une explosion de supernova.
Nous nous intéressons ensuite aux raies gamma de la décroissance de l'26Al et du 60Fe. Ces deux isotopes à longue durée de vie s'accumulent dans le milieu interstellaire autour des étoiles massives et donnent lieu à une émission galactique diffuse à 1809 et 1173/1332 keV respectivement. Les observations SPI de cette émission sont confrontées à un modèle de la nucléosynthèse galactique construit à partir des plus récents modèles stellaires. Un travail plus détaillé est alors consacré à la région du Cygne, qui abrite une forte concentration d'étoiles massives proches. Les données SPI obtenues sont comparées aux prédictions théoriques d'un code de synthèse de population et d'une simulation numérique de diffusion de l'26Al à l'intérieur de la superbulle soufflée par l'amas Cyg OB2.
Kerzendorf, Wolfgang Eitel. "Type Ia supernovae: explosions and progenitors." Phd thesis, 2011. http://hdl.handle.net/1885/10267.
Full textGhavamian, Parviz. "Optical spectroscopy and numerical modeling of nonradiative shocks in supernova remnants." Thesis, 2000. http://hdl.handle.net/1911/19497.
Full textSutherland, Ralph S. "Interstellar shock fluorescence." Phd thesis, 1993. http://hdl.handle.net/1885/138720.
Full textHsiao, Yi Chi Eric. "Spectroscopic diversity of Type Ia supernovae." Thesis, 2009. http://hdl.handle.net/1828/1665.
Full textMarion, George Howard. "Use of near infrared spectra to probe the chemical structure of type Ia supernovae." Thesis, 2006. http://hdl.handle.net/2152/2771.
Full textBraun, Chelsea. "An Imaging and Spectroscopic Study of the Supernova Remnant RCW 103 (G332.4-0.4) with the CHANDRA X-ray Observatory." 2016. http://hdl.handle.net/1993/31185.
Full textMay 2016
Lajoie, Charles-Philippe. "Recherche de systèmes binaires d'étoiles naines blanches par comparaison des paramètres atmosphériques obtenus à partir des spectres visibles et ultraviolets." Thèse, 2005. http://hdl.handle.net/1866/17354.
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