A Theory for Neutron Star and Black Hole Kicks and Induced Spins

Using twenty long-term 3D core-collapse supernova simulations, we find that lower compactness progenitors that explode quasi-spherically due to the short delay to explosion experience smaller neutron star recoil kicks in the $\sim$100$-$200 km s$^{-1}$ range, while higher compactness progenitors that explode later and more aspherically leave neutron stars with kicks in the $\sim$300$-$1000 km s$^{-1}$ range. In addition, we find that these two classes are correlated with the gravitational mass of the neutron star. This correlation suggests that the survival of binary neutron star systems may in part be due to their lower kick speeds. We also find a correlation of the kick with both the mass dipole of the ejecta and the explosion energy. Furthermore, one channel of black hole birth leaves masses of $\sim$10 $M_{\odot}$, is not accompanied by a neutrino-driven explosion, and experiences small kicks. A second is through a vigorous explosion that leaves behind a black hole with a mass of $\sim$3.0 $M_{\odot}$ kicked to high speeds. We find that the induced spins of nascent neutron stars range from seconds to $\sim$10 milliseconds, {but do not yet see a significant spin/kick correlation for pulsars.} We suggest that if an initial spin biases the explosion direction, a spin/kick correlation {would be} a common byproduct of the neutrino mechanism of core-collapse supernovae. Finally, the induced spin in explosive black hole formation is likely large and in the collapsar range. This new 3D model suite provides a greatly expanded perspective and appears to explain some observed pulsar properties by default.Comment: 16 pages, 7 figures. Accepted to Ap

The Essential Character of the Neutrino Mechanism of Core-Collapse Supernova Explosions

Calibrating with detailed 2D core-collapse supernova simulations, we derive a simple core-collapse supernova explosion condition based solely upon the terminal density profiles of state-of-the-art stellar evolution calculations of the progenitor massive stars. This condition captures the vast majority of the behavior of the one hundred 2D state-of-the-art models we performed to gauge its usefulness. The goal is to predict, without resort to detailed simulation, the explodability of a given massive star. We find that the simple maximum fractional ram pressure jump discriminant we define works well ~90% of the time and we speculate on the origin of the few false positives and false negatives we witness. The maximum ram pressure jump generally occurs at the time of accretion of the silicon/oxygen interface, but not always. Our results depend upon the fidelity with which the current implementation of our code Fornax adheres to Nature and issues concerning the neutrino-matter interaction, the nuclear equation of state, the possible effects of neutrino oscillations, grid resolution, the possible role of rotation and magnetic fields, and the accuracy of the numerical algorithms employed remain to be resolved. Nevertheless, the explodability condition we obtain is simple to implement, shows promise that it might be further generalized while still employing data from only the unstable Chandrasekhar progenitors, and is a more credible and robust simple explosion predictor than can currently be found in the literature.Comment: 20 pages, 17 figures. Accepted by MNRA

Structure and Morphology Effects on the Optical Properties of Bimetallic Nanoparticle Films Laser Deposited on a Glass Substrate

International audienceMoving nanosecond laser system is used for laser-assisted thermodiffusion deposition of metallic nanoparticles from water-based colloidal solutions. The results obtained for both gold and silver nanoparticles show that film morphology strongly depends on laser scanning speed and the number of passages. We show, furthermore, the possibility of producing bimetallic Au:Ag thin films by laser irradiation of the mixed solutions. As a result of several laser scans, granular nanometric films are found to grow with a well-controlled composition, thickness, and morphology. By changing laser scanning parameters, film morphology can be varied from island structures to quasi-periodic arrays. The optical properties of the deposited structures are found to depend on the film composition, thickness, and mean separation between the particles. The transparency spectra of the deposited films are shown to be defined by their morphology

The Gravitational-Wave Signature of Core-Collapse Supernovae

We calculate the gravitational-wave (GW) signatures of detailed 3D core-collapse supernova simulations spanning a range of massive stars. Most of the simulations are carried out to times late enough to capture more than 95% of the total GW emission. We find that the f/g-mode and f-mode of proto-neutron star oscillations carry away most of the GW power. The f-mode frequency inexorably rises as the proto-neutron star (PNS) core shrinks. We demonstrate that the GW emission is excited mostly by accretion plumes onto the PNS that energize modal oscillations and also high-frequency (``haze") emission correlated with the phase of violent accretion. The duration of the major phase of emission varies with exploding progenitor and there is a strong correlation between the total GW energy radiated and the compactness of the progenitor. Moreover, the total GW emissions vary by as much as three orders of magnitude from star to star. For black-hole formation, the GW signal tapers off slowly and does not manifest the haze seen for the exploding models. For such failed models, we also witness the emergence of a spiral shock motion that modulates the GW emission at a frequency near $\sim$100 Hertz that slowly increases as the stalled shock sinks. We find significant angular anisotropy of both the high- and low-frequency (memory) GW emissions, though the latter have very little power.Comment: submitted to PR

ГЛОБАЛЬНАЯ ЭНДОДРЕНАЖНАЯ СИСТЕМА: НЕКОТОРЫЕ ФЛЮИДОФИЗИЧЕСКИЕ МЕХАНИЗМЫ ГЕОДИНАМИЧЕСКИХ ПРОЦЕССОВ

The article presents the main results of more than forty-year studies of the hydrogeodeformation field. We have establish some new properties of lithospheric massifs, which are clearly detectable during the periods of fast geodynamic activation (FGeDA). These processes are contrastingly manifested within the planetary megastructure – the Global Endodrainage System (GEDS) of the Earth. The article discusses ideas about the conditions of formation, the specific features of functioning and the role of the asthenosphere as an essential element of the GEDS. It shows the dominant role of fluid processes that take place in the GEDS and provide the conditions for the ‘maturation’ of geodynamic catastrophes. The features of the formation of deformation disturbances and the dominant directions of the planetary migration of deformation impulses from the places of future catastrophic seismic events along the GEDS are considered. The regional hydrogeodeformation monitoring (HDGM) results give evidence of a close relationship between the lithospheric massifs in distant regions of the Earth: replica signals along the GDES length repeat an initial impulse originating from the area of a future seismic event. Attention is given to trigger effects that cause a seismic energy discharge at a large distance and, in some cases, can cause a cascade of earthquakes. It is proposed to create a HDGM system for monitoring of large seismic regions of the Earth.В статье рассматриваются основные результаты более чем сорокалетних исследований гидрогеодеформационного поля, которые позволили установить некоторые новые свойства литосферных толщ, особенно четко проявленные в периоды скоротечной геодинамической активизации. Эти процессы контрастно прослеживаются в пределах планетарной мегаструктуры – глобальной эндодренажной системы (ГЭДС) Земли. Предлагаются к обсуждению представления об условиях формирования, специфических особенностях функционирования и роли астеносферы как важнейшего элемента ГЭДС.Показана доминантная роль флюидных процессов, которые в пределах ГЭДС обеспечивают условия «созревания» геодинамических катастроф. Рассматриваются особенности формирования деформационных возмущений и господствующие направления планетарной миграции деформационных импульсов от мест будущей сейсмической катастрофы вдоль ГЭДС. Излагаются результаты регионального гидрогеодеформационного (ГГД) мониторинга, свидетельствующие о тесной связи литосферных массивов в удаленных друг от друга регионах Земли: сигналы-реплики вдоль протяженности ГЭДС повторяют первоначальный импульс, зародившийся в регионе будущего сейсмического события. Рассматриваются триггерные эффекты, вызывающие срыв сейсмической энергии на большом удалении и в некоторых случаях способные вызвать каскад землетрясений. Предлагается создание системы ГГД-мониторинга крупных сейсмоопасных регионов Земли

4-(4-Chloro­phen­yl)-4-hy­droxy­piperidinium benzoate

In the title salt, C11H15ClNO+·C7H5O2 −, the dihedral angle between the mean planes of the chloro­phenyl ring of the cation and the benzene ring of the anion is 74.4 (1)°. In the cation, the six-membered piperazine ring adopts a chair conformation. The crystal packing is stabilized by inter­molecular N—H⋯O and O—H⋯O hydrogen bonds, and weak inter­molecular C—H⋯O, C—H⋯Cl and C—H⋯π inter­actions

Structure and Morphology Effects on the Optical Properties of Bimetallic Nanoparticle Films Laser Deposited on a Glass Substrate

Moving nanosecond laser system is used for laser-assisted thermodiffusion deposition of metallic nanoparticles from water-based colloidal solutions. The results obtained for both gold and silver nanoparticles show that film morphology strongly depends on laser scanning speed and the number of passages. We show, furthermore, the possibility of producing bimetallic Au:Ag thin films by laser irradiation of the mixed solutions. As a result of several laser scans, granular nanometric films are found to grow with a well-controlled composition, thickness, and morphology. By changing laser scanning parameters, film morphology can be varied from island structures to quasi-periodic arrays. The optical properties of the deposited structures are found to depend on the film composition, thickness, and mean separation between the particles. The transparency spectra of the deposited films are shown to be defined by their morphology

Sensor Development for Single-Photon Thermoelectric Detectors

As we reported earlier [1], thermoelectric detectors can be competitive as nondispersive energy resolving focal-plane instruments in X-ray/UV spectrum. The first generations of prototype devices demonstrated the viability of detector design and provided good agreement between theoretical expectations and experimental data. These devices exploited sensors made of gold with a small fraction of iron impurity. To get the projected high resolution one needs another type of material, namely, lanthanum-cerium hexaborides. We report on the first experimental tests of the feasibility of lanthanum-cerium films as sensor materials. Progress with thin films of these materials argues for the success of these thermoelectric detectors

4-(4-Chloro­phen­yl)-4-hy­droxy­piperidinium 2-(2-phenyl­eth­yl)benzoate

In the title compound, C11H15ClNO+·C15H13O2 −, the piperidinium ring adopts a chair conformation. In the crystal, cations and anions are connected by inter­molecular O—H⋯O and N—H⋯O hydrogen bonds, forming two-dimensional networks parallel to the bc plane. Furthermore, the crystal structure is stabilized by weak C—H⋯π inter­actions