Niemeyer, J

[["dc.bibliographiccitation.firstpage","1683"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","The Astrophysical Journal"],["dc.bibliographiccitation.lastpage","1693"],["dc.bibliographiccitation.volume","710"],["dc.contributor.author","Schmidt, W."],["dc.contributor.author","Ciaraldi-Schoolmann, F."],["dc.contributor.author","Niemeyer, J. C."],["dc.contributor.author","Roepke, F. K."],["dc.contributor.author","Hillebrandt, W."],["dc.date.accessioned","2018-11-07T08:45:52Z"],["dc.date.accessioned","2020-07-02T14:45:12Z"],["dc.date.available","2018-11-07T08:45:52Z"],["dc.date.available","2020-07-02T14:45:12Z"],["dc.date.issued","2010"],["dc.description.abstract","The delayed detonation model describes the observational properties of the majority of Type Ia supernovae very well. Using numerical data from a three-dimensional deflagration model for Type Ia supernovae, the intermittency of the turbulent velocity field and its implications on the probability of a deflagration-to-detonation (DDT) transition are investigated. From structure functions of the turbulent velocity fluctuations, we determine intermittency parameters based on the log-normal and the log-Poisson models. The bulk of turbulence in the ash regions appears to be less intermittent than predicted by the standard log-normal model and the She-Leveque model. On the other hand, the analysis of the turbulent velocity fluctuations in the vicinity of the flame front by Ropke suggests a much higher probability of large velocity fluctuations on the grid scale in comparison to the log-normal intermittency model. Following Pan et al., we computed probability density functions for a DDT for the different distributions. The determination of the total number of regions at the flame surface, in which DDTs can be triggered, enables us to estimate the total number of events. Assuming that a DDT can occur in the stirred flame regime, as proposed by Woosley et al., the log-normal model would imply a delayed detonation between 0.7 and 0.8 s after the beginning of the deflagration phase for the multi-spot ignition scenario used in the simulation. However, the probability drops to virtually zero if a DDT is further constrained by the requirement that the turbulent velocity fluctuations reach about 500 km s(-1). Under this condition, delayed detonations are only possible if the distribution of the velocity fluctuations is not log-normal. From our calculations follows that the distribution obtained by Ropke allow for multiple DDTs around 0.8 s after ignition at a transition density close to 1 x 107 g cm(-3)."],["dc.identifier.doi","10.1088/0004-637X/710/2/1683"],["dc.identifier.isi","000274233300061"],["dc.identifier.scopus","2-s2.0-77149168162"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/20548"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-77149168162&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.eissn","1538-4357"],["dc.relation.issn","0004-637X"],["dc.title","Turbulence in a three-dimensional deflagration model for type Ia Supernovae. II. Intermittency and the deflagration-to-detonation transition probability"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Physical Review. D"],["dc.bibliographiccitation.volume","64"],["dc.contributor.author","Kempf, Achim"],["dc.contributor.author","Niemeyer, Jens C."],["dc.date.accessioned","2020-07-01T08:35:39Z"],["dc.date.available","2020-07-01T08:35:39Z"],["dc.date.issued","2001"],["dc.description.abstract","It has been pointed out that the perturbation spectrum predicted by inflation may be sensitive to a natural ultraviolet cutoff, thus potentially providing an experimentally accessible window to aspects of Planck scale physics. A priori, a natural ultraviolet cutoff could take any form, but a fairly general classification of possible Planck scale cutoffs has been given. One of those categorized cutoffs, also appearing in various studies of quantum gravity and string theory, has recently been implemented into the standard inflationary scenario. Here, we continue this approach by investigating its effects on the predicted perturbation spectrum. We find that the size of the effect depends sensitively on the scale separation between cutoff and horizon during inflation."],["dc.identifier.doi","10.1103/physrevd.64.103501"],["dc.identifier.scopus","2-s2.0-0035890670"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66820"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-0035890670&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.relation.eissn","1089-4918"],["dc.relation.issn","0556-2821"],["dc.title","Perturbation spectrum in inflation with a cutoff"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","058"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Journal of High Energy Physics"],["dc.bibliographiccitation.volume","2010"],["dc.contributor.author","Staub, F."],["dc.contributor.author","Niemeyer, J."],["dc.contributor.author","Porod, W."],["dc.date.accessioned","2018-11-07T08:47:59Z"],["dc.date.accessioned","2020-07-07T08:16:05Z"],["dc.date.available","2018-11-07T08:47:59Z"],["dc.date.available","2020-07-07T08:16:05Z"],["dc.date.issued","2010"],["dc.description.abstract","We reconsider the dark matter problem in supersymmetric models with gauge mediated supersymmetry breaking, with and without R-parity breaking. In these classes of models, a light gravitino forms the dark matter.Consistency with the experimental data, in particular the dark matter abundance and the small-scale power spectrum, requires additional entropy production after the decoupling of the gravitino from the thermal bath. We demonstrate that the usual mechanism via messenger number violating interactions does not work in models where the messenger belongs to SU (5) representations. This is mainly a consequence of two facts: (i) there are at least two different types of lightest messenger particles and (ii) the lightest messenger particle with SU (2) quantum numbers decays dominantly into vector bosons once messenger number is broken, a feature which has been overlooked so far. In case of SO(10) messenger multiplets we find scenarios which work if the SM gauge singlet component is rather light."],["dc.description.sponsorship","DFG [GRK-1147]; DAAD [D/07/13468]"],["dc.identifier.doi","10.1007/JHEP01(2010)058"],["dc.identifier.isi","000273717700029"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/7632"],["dc.identifier.scopus","2-s2.0-77954993426"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21090"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-77954993426&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1029-8479"],["dc.rights","Goescholar"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.title","Strong dark matter constraints on GMSB models"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Physical Review. D"],["dc.bibliographiccitation.volume","76"],["dc.contributor.author","Campo, David"],["dc.contributor.author","Niemeyer, Jens"],["dc.contributor.author","Parentani, Renaud"],["dc.date.accessioned","2020-07-22T09:54:30Z"],["dc.date.available","2020-07-22T09:54:30Z"],["dc.date.issued","2007"],["dc.description.abstract","We reconsider trans-Planckian corrections to inflationary spectra by taking into account a physical effect which has been overlooked and which could have important consequences. We assume that the short length scale characterizing the new physics is endowed with a finite width, the origin of which could be found in quantum gravity. As a result, the leading corrections responsible for superimposed osillations in the CMB temperature anisotropies are generically damped by the blurring of the UV scale. To determine the observational ramifications of this damping, we compare it to that which effectively occurs when computing the angular power spectrum of temperature anisotropies. The former gives an overall change of the oscillation amplitudes whereas the latter depends on the angular scale. Therefore, in principle they could be distinguished. In any case, the observation of superimposed oscillations would place tight constraint on the variance of the UV cutoff."],["dc.identifier.doi","10.1103/PhysRevD.76.023513"],["dc.identifier.scopus","2-s2.0-34547178724"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67397"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-34547178724&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.relation.issn","1550-7998"],["dc.relation.issn","1550-2368"],["dc.title","Damped corrections to inflationary spectra from a fluctuating cutoff"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","207"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","212"],["dc.bibliographiccitation.volume","451"],["dc.contributor.author","Maier, A."],["dc.contributor.author","Niemeyer, J. C."],["dc.date.accessioned","2020-07-01T08:38:21Z"],["dc.date.available","2020-07-01T08:38:21Z"],["dc.date.issued","2006"],["dc.description.abstract","In the context of explosion models for Type Ia Supernovae, we present one- and two-dimensional simulations of fully resolved detonation fronts in degenerate C+O White Dwarf matter including clumps of previously burned material. The ability of detonations to survive the passage through sheets of nuclear ashes is tested as a function of the width and composition of the ash region. We show that detonation fronts are quenched by microscopically thin obstacles with little sensitivity to the exact ash composition. Front-tracking models for detonations in macroscopic explosion simulations need to include this effect in order to predict the amount of unburned material in delayed detonation scenarios."],["dc.identifier.doi","10.1051/0004-6361:20054094"],["dc.identifier.scopus","2-s2.0-33646535322"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66821"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-33646535322&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.relation.eissn","1432-0746"],["dc.relation.issn","0004-6361"],["dc.title","C+O detonations in thermonuclear supernovae: Interaction with previously burned material"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","A31"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","614"],["dc.contributor.author","Behrens, Christoph"],["dc.contributor.author","Byrohl, Chris"],["dc.contributor.author","Saito, Shun"],["dc.contributor.author","Niemeyer, Jens C."],["dc.date.accessioned","2020-07-01T08:28:01Z"],["dc.date.available","2020-07-01T08:28:01Z"],["dc.date.issued","2017"],["dc.description.abstract","Lyman-$\\alpha$ emitters (LAEs) are a promising probe of the large-scale structure at high redshift, \\gtrsim 2$. In particular, the Hobby-Eberly Telescope Dark Energy Experiment aims at observing LAEs at 1.9 $<z<$ 3.5 to measure the Baryon Acoustic Oscillation (BAO) scale and the Redshift-Space Distortion (RSD). However, Zheng et al. (2011) pointed out that the complicated radiative transfer (RT) of the resonant Lyman-$\\alpha$ emission line generates an anisotropic selection bias in the LAE clustering on large scales, \\gtrsim 10$ Mpc. This effect could potentially induce a systematic error in the BAO and RSD measurements. Also, Croft et al. (2016) claims an observational evidence of the effect in the Lyman-$\\alpha$ intensity map, albeit statistically insignificant. We aim at quantifying the impact of the Lyman-$\\alpha$ RT on the large-scale galaxy clustering in detail. For this purpose, we study the correlations between the large-scale environment and the ratio of an apparent Lyman-$\\alpha$ luminosity to an intrinsic one, which we call the 'observed fraction', at <z<6$. We apply our Lyman-$\\alpha$ RT code by post-processing the full Illustris simulations. We simply assume that the intrinsic luminosity of the Lyman-$\\alpha$ emission is proportional to the star formation rate of galaxies in Illustris, yielding a sufficiently large sample of LAEs to measure the anisotropic selection bias. We find little correlations between large-scale environment and the observed fraction induced by the RT, and hence a smaller anisotropic selection bias than what was claimed by Zheng et al. (2011). We argue that the anisotropy was overestimated in the previous work due to the insufficient spatial resolution: it is important to keep the resolution such that it resolves the high density region down to the scale of the interstellar medium, $\\sim1$ physical kpc. (abridged)"],["dc.identifier.arxiv","1710.06171v2"],["dc.identifier.doi","10.1051/0004-6361/201731783"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66816"],["dc.language.iso","en"],["dc.relation.eissn","1432-0746"],["dc.relation.issn","0004-6361"],["dc.title","The impact of Lyman-$α$ radiative transfer on large-scale clustering in the Illustris simulation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","184"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE-ZEITSCHRIFT FUR PFLANZENERNAHRUNG UND BODENKUNDE"],["dc.bibliographiccitation.lastpage","188"],["dc.bibliographiccitation.volume","167"],["dc.contributor.author","Pagel-Wieder, Sibylle"],["dc.contributor.author","Gessler, Frank"],["dc.contributor.author","Niemeyer, J."],["dc.contributor.author","Schroder, D."],["dc.date.accessioned","2018-11-07T10:50:01Z"],["dc.date.available","2018-11-07T10:50:01Z"],["dc.date.issued","2004"],["dc.description.abstract","The adsorption of the toxin from Bacillus thuringiensis (Bt-toxin), which is synthesized in genetically modified maize, on sterilized Na-montmorillonite and on H2O2-treated and untreated clay fractions of three soils from different sites were studied. All adsorption isotherms can be described by a linear isotherm. Although all clay fractions from the different soils show nearly the same mineralogical composition, we found different affinities ranging from k = 47.7 to k = 366.7 of the adsorbates for the Bt-toxin. The H2O2-treated clay fractions show no correlation between the adsorption affinity and the amount of soil organic matter. On the other hand, there is a correlation between the content of organic carbon and the adsorption affinity of the untreated clay fractions. This can be explained by the fact that due to the coatings of soil organic matter on aggregates, the Bt-toxin polymers are not able to adsorb within the clay aggregates."],["dc.identifier.doi","10.1002/jpln.200321312"],["dc.identifier.isi","000221004400008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48563"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1436-8730"],["dc.title","Adsorption of the Bacillus thuringiensis toxin (Cry1 Ab) on Na-montmorillonite and on the clay fractions of different soils"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3051"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Monthly Notices of the Royal Astronomical Society"],["dc.bibliographiccitation.lastpage","3077"],["dc.bibliographiccitation.volume","440"],["dc.contributor.author","Schmidt, W."],["dc.contributor.author","Almgren, A. S."],["dc.contributor.author","Braun, H."],["dc.contributor.author","Engels, Jan F."],["dc.contributor.author","Niemeyer, J. C."],["dc.contributor.author","Schulz, J."],["dc.contributor.author","Mekuria, R. R."],["dc.contributor.author","Aspden, A. J."],["dc.contributor.author","Bell, J. B."],["dc.date.accessioned","2018-11-07T09:39:46Z"],["dc.date.accessioned","2020-07-16T12:51:32Z"],["dc.date.available","2018-11-07T09:39:46Z"],["dc.date.available","2020-07-16T12:51:32Z"],["dc.date.issued","2013"],["dc.description.abstract","We investigate turbulence generated by cosmological structure formation by means of large eddy simulations using adaptive mesh refinement. In contrast to the widely used implicit large eddy simulations, which resolve a limited range of length scales and treat the effect of turbulent velocity fluctuations below the grid scale solely by numerical dissipation, we apply a subgrid-scale model for the numerically unresolved fraction of the turbulence energy. For simulations with adaptive mesh refinement, we utilize a new methodology that allows us to adjust the scale-dependent energy variables in such a way that the sum of resolved and unresolved energies is globally conserved. We test our approach in simulations of randomly forced turbulence, a gravitationally bound cloud in a wind, and the Santa Barbara cluster. To treat inhomogeneous turbulence, we introduce an adaptive Kalman filtering technique that separates turbulent velocity fluctuations on resolved length scales from the non-turbulent bulk flow. From the magnitude of the fluctuating component and the subgrid-scale turbulence energy, a total turbulent velocity dispersion of several 100 km/s is obtained for the Santa Barbara cluster, while the low-density gas outside the accretion shocks is nearly devoid of turbulence. The energy flux through the turbulent cascade and the dissipation rate predicted by the subgrid-scale model correspond to dynamical time scales around 5 Gyr, independent of numerical resolution."],["dc.identifier.doi","10.1093/mnras/stu501"],["dc.identifier.isi","000336213800015"],["dc.identifier.scopus","2-s2.0-84899826562"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67192"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-84899826562&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.eissn","0035-8711"],["dc.relation.issn","1365-2966"],["dc.title","Cosmological fluid mechanics with adaptively refined large eddy simulations"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","952"],["dc.bibliographiccitation.issue","2 I"],["dc.bibliographiccitation.journal","The Astrophysical Journal"],["dc.bibliographiccitation.lastpage","961"],["dc.bibliographiccitation.volume","588"],["dc.contributor.author","Röpke, F. K."],["dc.contributor.author","Niemeyer, J. C."],["dc.contributor.author","Hillebrandt, W."],["dc.date.accessioned","2020-07-21T06:08:10Z"],["dc.date.available","2020-07-21T06:08:10Z"],["dc.date.issued","2003"],["dc.description.abstract","We present a numerical model which allows us to investigate thermonuclear flames in Type Ia supernova explosions. The model is based on a finite-volume explicit hydrodynamics solver employing PPM. Using the level-set technique combined with in-cell reconstruction and flux-splitting schemes we are able to describe the flame in the discontinuity approximation. We apply our implementation to flame propagation in Chandrasekhar-mass Type Ia supernova models. In particular we concentrate on intermediate scales between the flame width and the Gibson-scale, where the burning front is subject to the Landau-Darrieus instability. We are able to reproduce the theoretical prediction on the growth rates of perturbations in the linear regime and observe the stabilization of the flame in a cellular shape. The increase of the mean burning velocity due to the enlarged flame surface is measured. Results of our simulation are in agreement with semianalytical studies."],["dc.identifier.doi","10.1086/374216"],["dc.identifier.scopus","2-s2.0-0041760782"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/67316"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-0041760782&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.relation.eissn","1538-4357"],["dc.relation.issn","0004-637X"],["dc.title","On the small-scale stability of thermonuclear flames in type ia supernovae"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","993"],["dc.bibliographiccitation.issue","2 PART 1"],["dc.bibliographiccitation.journal","The Astrophysical Journal"],["dc.bibliographiccitation.lastpage","997"],["dc.bibliographiccitation.volume","537"],["dc.contributor.author","Timmes, F. X."],["dc.contributor.author","Niemeyer, J. C."],["dc.date.accessioned","2020-07-09T08:41:37Z"],["dc.date.available","2020-07-09T08:41:37Z"],["dc.date.issued","2000"],["dc.description.abstract","The burning regimes encountered by laminar deflagrations and Zeldovich von Neumann Döring (ZND) detonations propagating through helium-rich compositions in the presence of buoyancy-driven turbulence are analyzed. Particular attention is given to models of X-ray bursts that start with a thermonuclear runaway on the surface of a neutron star and to the thin-shell helium instability of intermediate-mass stars. In the X-ray burst case, turbulent deflagrations propagating in the lateral or radial direction encounter a transition from the distributed regime to the flamelet regime at a density of ~108 g cm-3. In the radial direction, the purely laminar deflagration width is larger than the pressure scale height for densities smaller than ~106 g cm-3. Self-sustained laminar deflagrations traveling in the radial direction cannot exist below this density. Similarly, the planar ZND detonation width becomes larger than the pressure scale height at ~107 g cm-3, suggesting that steady state, self-sustained detonations cannot come into existence in the radial direction. In the thin helium shell case, turbulent deflagrations traveling in the lateral or radial direction encounter the distributed regime at densities below ~107 g cm-3 and the flamelet regime at larger densities. In the radial direction, the purely laminar deflagration width is larger than the pressure scale height for densities smaller than ~104 g cm-3, indicating that steady state laminar deflagrations cannot form below this density. The planar ZND detonation width becomes larger than the pressure scale height at ~5 × 104 g cm-3, suggesting that steady state, self-sustained detonations cannot come into existence in the radial direction."],["dc.identifier.doi","10.1086/309043"],["dc.identifier.scopus","2-s2.0-0034408916"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66906"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-0034408916&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.relation.issn","0004-637X"],["dc.title","Regimes of Helium Burning"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]