Niemeyer, J

[["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","386"],["dc.contributor.author","Reinecke, M."],["dc.contributor.author","Hillebrandt, W."],["dc.contributor.author","Niemeyer, J. C."],["dc.date.accessioned","2020-07-03T07:18:17Z"],["dc.date.available","2020-07-03T07:18:17Z"],["dc.date.issued","2002"],["dc.identifier.scopus","2-s2.0-0036570811"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66852"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-0036570811&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.title","Refined numerical models for multidimensional type Ia supernova simulations"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.volume","11"],["dc.contributor.author","Hillebrandt, W."],["dc.contributor.author","Reinecke, M."],["dc.contributor.author","Röpke, F. K."],["dc.contributor.author","Stehle, M."],["dc.contributor.author","Travaglio, C."],["dc.contributor.author","Niemeyer, J. C."],["dc.contributor.editor","Jorissen, A."],["dc.contributor.editor","Goriely, S."],["dc.contributor.editor","Rayet, M."],["dc.contributor.editor","Siess, L."],["dc.contributor.editor","Boffin, H."],["dc.date.accessioned","2020-07-16T13:04:44Z"],["dc.date.available","2020-07-16T13:04:44Z"],["dc.date.issued","2004"],["dc.description.abstract","Recent progress in modeling type Ia supernovae by means of 3-dimensional hydrodynamic simulations as well as several of the still open questions are addressed. Our models are based on the assumption that thermonuclear burning inside a Chandrasekhar-mass C+O white dwarf is similar to turbulent chemical combustion and that, thus, thermonuclear supernovae can be modeled by means of numerical methods which have been developed and tested for laboratory and technical flames. It is shown that the new models have considerable predictive power and allow to study observable properties of type Ia supernovae, such as their light curves and spectra, without adjustable non-physical parameters, and they make firm predictions for the nucleosynthesis yields from the explosions. This raises a quest for better data, covering the spectroscopical and photometric evolution in all wave bands from very early epochs all the way into the nebular phase. First such results obtained by the European Supernova Collaboration (ESC) for a sample of nearby SNe Ia and their implications for constraining the models and systematic differences between them are also discussed."],["dc.identifier.doi","10.1051/eas:2004010"],["dc.identifier.scopus","2-s2.0-28844472915"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67196"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-28844472915&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.publisher","EDP Sciences"],["dc.relation.crisseries","EAS Publications Series"],["dc.relation.ispartofseries","EAS Publications Series;"],["dc.title","Thermonuclear supernovae"],["dc.type","book"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","229"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Nuclear Physics. A, Nuclear and Hadronic Physics"],["dc.bibliographiccitation.lastpage","238"],["dc.bibliographiccitation.volume","723"],["dc.contributor.author","Hillebrandt, W."],["dc.contributor.author","Niemeyer, J. C."],["dc.contributor.author","Reinecke, M."],["dc.contributor.author","Röpke, F."],["dc.contributor.author","Travaglio, C."],["dc.date.accessioned","2020-07-22T09:29:46Z"],["dc.date.available","2020-07-22T09:29:46Z"],["dc.date.issued","2003"],["dc.description.abstract","Because calibrated light curves of type Ia supernovae have become a major tool to determine the local expansion rate of the Universe, considerable attention has been given to models of these events over the past couple of years. It is now common believe that perhaps most type Ia supernovae are the explosions of white dwarfs that have approached the Chandrasekhar mass, MChan, ≈ 1.39 M⊙, and are disrupted by thermonuclear fusion of carbon and oxygen. However, the mechanism whereby such accreting carbon-oxygen white dwarfs explode continues to be uncertain. Recent progress in modeling type Ia supernovae as well as several of the still open questions are addressed in this article. Although the main emphasis will be on studies of the explosion mechanism itself and on the related physical processes, including the physics and nuclear physics of turbulent nuclear combustion in degenerate stars, observational implications and constraints will also be discussed."],["dc.identifier.doi","10.1016/S0375-9474(03)00719-X"],["dc.identifier.scopus","2-s2.0-0038181127"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67381"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-0038181127&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.relation.issn","0375-9474"],["dc.title","Multidimensional simulations of type Ia supernova explosions and nucleosynthesis"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","363"],["dc.bibliographiccitation.lastpage","384"],["dc.contributor.author","Hillebrandt, W."],["dc.contributor.author","Reinecke, M."],["dc.contributor.author","Schmidt, W."],["dc.contributor.author","Röpke, F. K."],["dc.contributor.author","Travaglio, C."],["dc.contributor.author","Niemeyer, J. C."],["dc.contributor.editor","Warnecke, G."],["dc.date.accessioned","2020-07-09T08:04:23Z"],["dc.date.available","2020-07-09T08:04:23Z"],["dc.date.issued","2005"],["dc.description.abstract","Type Ia supernovae, i.e. stellar explosions which do not have hydrogen in their spectra, but intermediate-mass elements such as silicon, calcium, cobalt, and iron, have recently received considerable attention because it appears that they can be used as ”standard candles” to measure cosmic distances out to billions of light years away from us. Observations of type Ia supernovae seem to indicate that we are living in a universe that started to accelerate its expansion when it was about half its present age. These conclusions rest primarily on phenomenological models which, however, lack proper theoretical understanding, mainly because the explosion process, initiated by thermonuclear fusion of carbon and oxygen into heavier elements, is difficult to simulate even on supercomputers. Here, we investigate a new way of modeling turbulent thermonuclear deflagration fronts in white dwarfs undergoing a type Ia supernova explosion. Our approach is based on a level set method which treats the front as a mathematical discontinuity and allows for full coupling between the front geometry and the flow field. New results of the method applied to the problem of type Ia supernovae are obtained. It is shown that in 2-D with high spatial resolution and a physically motivated subgrid scale model for the nuclear flames numerically “converged” results can be obtained, but for most initial conditions the stars do not explode. In contrast, simulations in 3-D do give the desired explosions and many of their properties, such as the explosion energies, lightcurves and nucleosynthesis products, are in very good agreement with observed type Ia supernovae."],["dc.identifier.doi","10.1007/3-540-27907-5_16"],["dc.identifier.scopus","2-s2.0-35348925773"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66897"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-35348925773&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.publisher","Springer"],["dc.publisher.place","Berlin, Heidelberg"],["dc.relation.doi","10.1007/3-540-27907-5"],["dc.relation.eisbn","978-3-540-27907-5"],["dc.relation.isbn","978-3-540-24834-7"],["dc.relation.ispartof","Analysis and Numerics for Conservation Laws"],["dc.title","Simulations of turbulent thermonuclear burning in type Ia supernovae"],["dc.type","book_chapter"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","481"],["dc.bibliographiccitation.issue","8-10"],["dc.bibliographiccitation.journal","New Astronomy Reviews"],["dc.bibliographiccitation.lastpage","486"],["dc.bibliographiccitation.volume","46"],["dc.contributor.author","Reinecke, M."],["dc.contributor.author","Niemeyer, J. C."],["dc.contributor.author","Hillebrandt, W."],["dc.date.accessioned","2020-07-09T08:45:48Z"],["dc.date.available","2020-07-09T08:45:48Z"],["dc.date.issued","2002"],["dc.description.abstract","In this article we discuss the first simulations of two- and three-dimensional Type Ia supernovae with an improved hydrodynamics code. After describing the various enhancements, the obtained results are compared to those of earlier code versions, observational data and the findings of other researchers in this field."],["dc.identifier.doi","10.1016/S1387-6473(02)00187-2"],["dc.identifier.scopus","2-s2.0-0036315915"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66908"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-0036315915&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.relation.issn","1387-6473"],["dc.title","On the explosion mechanism of SNe type Ia"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","347"],["dc.contributor.author","Reinecke, M."],["dc.contributor.author","Hillebrandt, W."],["dc.contributor.author","Niemeyer, J. C."],["dc.date.accessioned","2020-07-22T09:35:07Z"],["dc.date.available","2020-07-22T09:35:07Z"],["dc.date.issued","1999"],["dc.description.abstract","First results of simulations are presented which compute the dynamical evolution of a Chandrasekhar-mass white dwarf, consisting of equal amounts of carbon and oxygen, from the onset of violent thermonuclear burning, by means of a new two-dimensional numerical code. Since in the interior of such a massive white dwarf nuclear burning progresses on microscopic scales as a sharp discontinuity, a so-called flamelet which cannot be resolved by any numerical scheme, and since on macroscopic scales the burning front propagates due to turbulence, we make an attempt to model both effects explicitly in the framework of a finite-volume hydrodynamics code. Turbulence is included by a sub-grid model, following the spirit of large eddy simulations, and the well-localized burning front is treated by means of a level set. which allows us to compute the geometrical structure of the front more accurately than with previous methods. The only free parameters of our simulations are the location and the amount of nuclear fuel that is ignited as an initial perturbation. We find that models in which explosive carbon burning is ignited at the center remain bound by the time the front reaches low densities, where we stopped the computations because our description of combustion is no longer applicable. In contrail, off-center ignition models give rise to explosions which, however, are still too weak for typical Type Ia supernovae. Possible reasons for this rather disappointing result are discussed."],["dc.identifier.scopus","2-s2.0-0001862101"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67386"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-0001862101&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.title","Thermonuclear explosions of Chandrasekhar-mass C+O white dwarfs"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","724"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","733"],["dc.bibliographiccitation.volume","347"],["dc.contributor.author","Reinecke, M."],["dc.contributor.author","Hillebrandt, W."],["dc.contributor.author","Niemeyer, J. C."],["dc.contributor.author","Klein, R."],["dc.contributor.author","Gröbl, A."],["dc.date.accessioned","2020-07-09T08:06:58Z"],["dc.date.available","2020-07-09T08:06:58Z"],["dc.date.issued","1999"],["dc.description.abstract","We present a new way of modeling deflagration fronts in reactive fluids, the main emphasis being on turbulent thermonuclear deflagration fronts in white dwarfs undergoing a Type la supernova explosion. Our approach is based on a level set method which treats the front as a mathematical discontinuity and allows full coupling between the front geometry and the flow field (Smiljanovski et al., 1997). With only minor modifications, this method can also be applied to describe contact discontinuities. Two different implementations ore described and their physically correct behaviour for simple testcases is shown. First results of the method applied to the concrete problems of Type la supernovae and chemical hydrogen combustion are briefly discussed; a more extensive analysis of our astrophysical simulations is given in Reinecke et al. (1998)."],["dc.identifier.scopus","2-s2.0-0000742902"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66898"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-0000742902&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.relation.issn","0004-6361"],["dc.title","A new model for deflagration fronts in reactive fluids"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","391"],["dc.contributor.author","Reinecke, M."],["dc.contributor.author","Hillebrandt, W."],["dc.contributor.author","Niemeyer, J. C."],["dc.date.accessioned","2020-07-20T10:12:23Z"],["dc.date.available","2020-07-20T10:12:23Z"],["dc.date.issued","2002"],["dc.identifier.scopus","2-s2.0-0036727460"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67257"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-0036727460&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.title","Three-dimensional simulations of type Ia supernovae"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]