Thermal X-Ray Emission from Shocked Ejecta in Type Ia Supernova Remnants II: Parameters Affecting the Spectrum

The supernova remnants left behind by Type Ia supernovae provide an excellent opportunity for the study of these enigmatic objects. In a previous work, we showed that it is possible to use the X-ray spectra of young Type Ia supernova remnants to explore the physics of Type Ia supernovae and identify the relevant mechanism underlying these explosions. Our simulation technique is based on hydrodynamic and nonequilibrium ionization calculations of the interaction of a grid of Type Ia explosion models with the surrounding ambient medium, coupled to an X-ray spectral code. In this work we explore the influence of two key parameters on the shape of the X-ray spectrum of the ejecta: the density of the ambient medium around the supernova progenitor and the efficiency of collisionless electron heating at the reverse shock. We also discuss the performance of recent 3D simulations of Type Ia SN explosions in the context of the X-ray spectra of young SNRs. We find a better agreement with the observations for Type Ia supernova models with stratified ejecta than for 3D deflagration models with well mixed ejecta. We conclude that our grid of Type Ia supernova remnant models can improve our understanding of these objects and their relationship to the supernovae that originated them.Comment: Accepted for publication in Ap

Evolución tectónica y sedimentaria durante el Priaboniense superior-Mioceno inferior, en el frente de cabalgamiento de las Sierras Marginales occidentales

Four systems tracts have been distinguished in the uppermost Eocene-lower Miocene continental deposits of the northern margin of the Ebro basin. 1) The Satinar systems tract 5pper Pnabonian-Stampian) consists of an alluvial system (Salinar Fm) located in the north, that passes to playa-lake evapontes (lower Barbastro Fm) towards the foreland. The alluvial sediments are represented only by distal fan and alluvial plain facies which are in the footwall of the Sierras Marginales thrust. The top of the Salinar systems tract is inarked by lacustrine limestones that represerit the alluvial fan retre,at and a change to less saline conditions. 2) The Peralta systems tract (upperPriaboniiin?-Stampian) consists of srnall alluvial fans attached to the Sierras Marginales (Peralta Fm) that pass to playa-lake evaporites towards ;he foreland (upper Barbastro Fm). The alluvial facies are represented by calcareous conglomerates, that grade in a few kilometers to thin-bedded sandstones and mudstones. Evaporitic facies are represented by nodular and larninated gypsum. The top of the Peralta systems tract is also marked by an extensive body of lacustrine carbonates that represent a new alluvial fan retreat. 3) The Peraltilla systems tract (Stampian-Chattian) consists of small alluvial fans (Calasanz Fm), that show i;imilar characteristics to those of the Peralta I'rn but they interfinger distally with a large fluvial systern sourced in the axial Pyrenees (Peraltilla Fm). This fluvial fan consists of red overbank deposits with paleosoils, and channelized bodies, which are mostly conglomeratic in the Azanuy syncline and become sandy towards the southern limb of Barbastro anticline. This granulometric change is accompanied by a change in channel type, from typical braided to sinuouir or straight. The Salinar and Peralta systerns are contemporaneous with the emplacernent of the Sierras Marginales thrust sheet. The clastic sedirnents accumulated in a flexura1 trough that widens while the thrust propagates. As a consecuence, the saline lake facies expand towards the foreland. During the Peralta systerns tract a blind detachment located in the base of the Barbastro evaporitic formation propagated and started to fold the foreland. The Peraltilla systems tract is contemporaneous with the end of displacement of the Sierras Marginales thrust sheet and the rnain growth of the Peralta detachment anticline. However, these tectonic events were accompanied by a significant forelandward shift of the basin depocenter and a more homogeneous subsidence. 4) The Sarinena systems tract (Chattian-Aquitanian) is very similar to the Peraltilla one but it shows a marked southwards shift of the proximal facies. It consists of srnall fans of local provenance (Baells Fm) that interfinger distally with alarge fluvial fan (Sarinena Fm). The sedimentation of the Sariñenasystems tract is contemporaneous with the continued southward propagation of the detachment through the foreland evaporites, that creates new detachment folds (Barbastro and Altarriba anticlines, Azanuy syncline). An episode of out-of sequence thrusting generates small thrust-top basins on the Sierras Marginales, filled by the Baells conglomerates. The Sariñena systems tract accumulated in a wide foreland trough, with a strongly subsiding located in the Azanuy syncline

Detailed Spectral Modeling of a 3-D Pulsating Reverse Detonation Model: Too Much Nickel

We calculate detailed NLTE synthetic spectra of a Pulsating Reverse Detonation (PRD) model, a novel explosion mechanism for Type Ia supernovae. While the hydro models are calculated in 3-D, the spectra use an angle averaged hydro model and thus some of the 3-D details are lost, but the overall average should be a good representation of the average observed spectra. We study the model at 3 epochs: maximum light, seven days prior to maximum light, and 5 days after maximum light. At maximum the defining Si II feature is prominent, but there is also a prominent C II feature, not usually observed in normal SNe Ia near maximum. We compare to the early spectrum of SN 2006D which did show a prominent C II feature, but the fit to the observations is not compelling. Finally we compare to the post-maximum UV+optical spectrum of SN 1992A. With the broad spectral coverage it is clear that the iron-peak elements on the outside of the model push too much flux to the red and thus the particular PRD realizations studied would be intrinsically far redder than observed SNe Ia. We briefly discuss variations that could improve future PRD models.Comment: 15 pages, 4 figures, submitted to Ap

Analysis of the temperature-dependent quantum point contact conductance in view of the metal-insulator transition in two dimensions

The temperature dependence of the conductance of a quantum point contact has been measured. The conductance as a function of the Fermi energy shows temperature-independent fixed points, located at roughly multiple integers of $e^{2}/h$. Around the first fixed point at e$^{2}$/h, the experimental data for different temperatures can been scaled onto a single curve. For pure thermal smearing of the conductance steps, a scaling parameter of one is expected. The measured scaling parameter, however, is significantly larger than 1. The deviations are interpreted as a signature of the potential landscape of the quantum point contact, and of the source-drain bias voltage. We relate our results phenomenologically to the metal-insulator transition in two dimensions.Comment: 5 pages, 3 figure

Geology of the Cotiella thrust sheet, southern Pyrenees (Spain)

This paper presents a geological map and cross-sections of the Cotiella thrust sheet at 1:25,000 and 1:50,000 scale, respectively. The map covers an area of 225 km2 in the southern Pyrenees. The structure of the studied area is dominated by an upper Santonian - lower Miocene thrust system, which transported a middle Coniacian-lower Santonian extensional basin, the Cotiella Basin, 10 s of kilometres southwards during the Pyrenean orogeny. The map focuses on the internal structure of the Cotiella Basin, its partially inverted extensional faults and its up to 6.5 km of upper Albian - lower Santonian sediments that unconformably overlie Upper Triassic salts. The map and cross-sections, together with outcrop-scale observations, have led us to interpret the rising of passive diapirs in the area. This newly recognized salt tectonic event in the Cotiella Basin is important because of the insights it can provide for the paleogeographic reconstruction of the Upper Cretaceous paleomargin of the northern parts of the Iberian Peninsula

Thermal Timescale Mass Transfer and the Evolution of White Dwarf Binaries

The evolution of binaries consisting of evolved main sequence stars (1 < M_d/Msun < 3.5) with white dwarf companions (0.7 < M_wd/Msun < 1.2) is investigated through the thermal mass transfer phase. Taking into account the stabilizing effect of a strong, optically thick wind from the accreting white dwarf surface, we have explored the formation of several evolutionary groups of systems for progenitors with initial orbital periods of 1 and 2 days. The numerical results show that CO white dwarfs can accrete sufficient mass to evolve to a Type Ia supernova and ONeMg white dwarfs can be built up to undergo accretion induced collapse for donors more massive than about 2 Msun. For donors less massive than ~2 Msun the system can evolve to form a He and CO or ONeMg white dwarf pair. In addition, sufficient helium can be accumulated (~0.1 Msun) in systems characterized by 1.6 < M_d/Msun < 1.9 and 0.8 < M_wd/Msun < 1 such that sub Chandrasekhar mass models for Type Ia supernovae, involving off center helium ignition, are possible for progenitor systems evolving via the Case A mass transfer phase. For systems characterized by mass ratios > 3 the system likely merges as a result of the occurrence of a delayed dynamical mass transfer instability. A semi-analytical model is developed to delineate these phases which can be easily incorporated in population synthesis studies of these systems.Comment: 9 pages, 6 figures, Latex, emulateapj style, ApJ accepte

Analysis of the Metallic Phase of Two-Dimensional Holes in SiGe in Terms of Temperature Dependent Screening

We find that temperature dependent screening can quantitatively explain the metallic behaviour of the resistivity on the metallic side of the so-called metal-insulator transition in p-SiGe. Interference and interaction effects exhibit the usual insulating behaviour which is expected to overpower the metallic background at sufficiently low temperatures. We find empirically that the concept of a Fermi-liquid describes our data in spite of the large r_s = 8.Comment: 4 pages, 3 figure

The effects of fermentation and enzymatic treatment of pea on nutrient digestibility and growth performance of broilers

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The present study examined the impacts of native, fermented or enzymatically treated peas (Pisum sativum L.) inclusion in broiler diets, on growth performance and nutrient digestibility. For the fermentation process, Madonna pea was mixed with water (1/1) containing 2.57×108 Bacillus subtilis (GalliPro®) spores/kg pea and then, incubated for 48 h at 30 °C. For the enzymatic treatment process, the used water for dough production contained three enzymes, AlphaGalTM (α-galactosidase), RONOZYME® ProAct and VP (protease and pectinases respectively – DSM, Switzerland) and the pea dough incubated for 24 h at 30°C. Nine corn-wheat-soybean diets were formulated by supplying 10%, 20% and 30% of the required CP with either native, fermented or enzymatically treated peas. Performance was recorded weekly and at the end of the experiment (day 35), apparent ileal digestibility (AID) of CP, amino acids (AA), crude fat, starch, Ca, P and K were determined. Data were subjected to ANOVA using GLM procedure with a 3×3 factorial arrangement of treatments. Both processes reduced α-galactosides, phytate, trypsin inhibitor activity and resistant starch in peas. Increasing levels of pea products up to 300 g/kg diet, reduced BW gain and feed intake (P⩽0.05). Broilers fed diets containing enzymatically treated pea had the best feed conversion ratio at day 35. Different types of pea product and their inclusion levels had no effect on AID of all nutrients. The interaction between type of the pea products and inclusion levels was significant for AID of starch. For native pea diets, 10% group showed similar AID of starch to 20% native pea but it had higher AID than 30% native pea. For fermented and enzymatically treated groups, all three levels displayed similar AID of starch. In conclusion, enzymatic treatment and fermentation could improve the nutritional quality of pea. Inclusion of enzymatically treated pea in broiler diets could improve broiler performance compared with other pea products while, it displayed neither positive nor negative impact on nutrient digestibility. The present findings indicate the feasibility of these processes, particularly enzymatic treatment, for improving the nutritional quality of pea as a protein source for broiler nutrition

Multi-spot ignition in type Ia supernova models

We present a systematic survey of the capabilities of type Ia supernova explosion models starting from a number of flame seeds distributed around the center of the white dwarf star. To this end we greatly improved the resolution of the numerical simulations in the initial stages. This novel numerical approach facilitates a detailed study of multi-spot ignition scenarios with up to hundreds of ignition sparks. Two-dimensional simulations are shown to be inappropriate to study the effects of initial flame configurations. Based on a set of three-dimensional models, we conclude that multi-spot ignition scenarios may improve type Ia supernova models towards better agreement with observations. The achievable effect reaches a maximum at a limited number of flame ignition kernels as shown by the numerical models and corroborated by a simple dimensional analysis.Comment: 14 pages, 12 figures with reduced resolution to meet astro-ph file size restriction, full-resolution version available from http://www.mpa-garching.mpg.de/~fritz/publications/astro-ph/multispot.pdf submitted to A&