Stability and chaos of hierarchical three black hole configurations

We study the stability and chaos of three compact objects using post-Newtonian (PN) equations of motion derived from the Arnowitt-Deser-Misner-Hamiltonian formulation. We include terms up to 2.5 PN order in the orbital part and the leading order in spin corrections. We performed numerical simulations of a hierarchical configuration of three compact bodies in which a binary system is perturbed by a third, lighter body initially positioned far away from the binary. The relative importance of the different PN orders is examined. The basin boundary method and the computation of Lyapunov exponent were employed to analyze the stability and chaotic properties of the system. The 1 PN terms produced a small but noticeable change in the stability regions of the parameters considered. The inclusion of spin or gravitational radiation does not produced a significant change with respect to the inclusion of the 1 PN terms.Comment: 16 pages, 17 figures and 4 tables. Version published in Phys. Rev. D. arXiv admin note: text overlap with arXiv:1012.442

Numerical simulations of three black holes

In dieser Arbeit wurde ein numerischer, elliptischer Löser, Olliptic, pr¨asentiert. Als erste Anwendung wurde die Hamiltonsche Zwangsbedingung gelöst, um numerische Anfangsdaten für Simulationen mit mehreren Schwarzen Löchern zu erhalten. Olliptic implementiert eine ”Multigrid”-Methode hoher Ordnung, die parallelisiert ist und Boxen-basierte Gitterverfeinerung verwendet. Die Tests und ersten Anwendungen des Codes zeigen, dass der neue Code für unsere Zwecke genau genug zu sein scheint. Allerdings fanden wir das Nahe an der Punktur die Konvergenz-Rate geringer ist als gewünscht, was man für Punktur Daten (siehe Anhang C) erwartet. Der Abfall der Konvergenz nahe der Punkturen spiegelt sich nicht in der Konvergenz der Zeitentwicklung wieder. Wir haben Entwicklungen von drei Schwarzen Löchern gezeigt, für deren Anfangsdaten die Lösungen der Hamiltonschen Zwangsbedingung, wie sie durch den neuen ellptischen Löser generiert wurden, verwendet wurden. Wir haben unsere Anfangsdaten mit denen einer bestimmten analytischen Näherung für Anfangsdaten verglichen. Im Falle dreier Schwarzer Löcher ist die aus den genäherten Anfangsdaten resultierende Dynamik von der in Zeitentwicklungen, die die Hamiltonsche Zwangsbedingung numerisch erfüllen, verschieden. Wie zu vermuten, sind die Trajektorien der Punkturen sensitiv auf kleine Änderungen in den Anfangsdaten. Besonders, für drei und mehr Schwarze Löcher kann eine Änderung der Anfangsdaten, z.B. durch das Lösen der Zwangsbedingungen statt eine analytische Näherung zu verwenden, zu qualitativ und quantitativ sehr unterschiedlichen Verschmelzungssequenzen führen. Dennoch haben wir die Resultate von [42, 94] bestätigt, wie erwartet, dass sich die Punktur Methode auf natürliche Weise für die Simulation mehrerer Schwarzer Löcher eignet. Simulationen dreier, vierer oder gar mehrerer Schwarzer Löcher führt zur der folgenden Frage ¨uber allgemeinere Verschmelzungs Situationen: Wie kann man die Anzahl der in einer Verschmelzung beteiligten Schwarzen Löchern aus der Beobachtung ihrer Gravitationswellen bestimmen? Eine erste Analyse dieses Themas wurde zuvor im Newtonschen Fall gegeben [9, 127]. Unter Verwendung Post-Newtonscher Techniken und voll relativistischer, numerischer Simulationen haben wir mit der Erforschung eines einfachen Falles begonnen, in dem wir Evidenz aufzeigen, die die anfängliche Vermutung von [127] unterstützt, welche wir hier umformulieren

Hydrodynamic Simulations of the Interaction between an AGB Star and a Main Sequence Companion in Eccentric Orbits

The Rotten Egg Nebula has at its core a binary composed of a Mira star and an A-type companion at a separation >10 au. It has been hypothesized to have formed by strong binary interactions between the Mira and a companion in an eccentric orbit during periastron passage ~800 years ago. We have performed hydrodynamic simulations of an asymptotic giant branch star interacting with companions with a range of masses in orbits with a range of initial eccentricities and periastron separations. For reasonable values of the eccentricity, we find that Roche lobe overflow can take place only if the periods are <<100 years. Moreover, mass transfer causes the system to enter a common envelope phase within several orbits. Since the central star of the Rotten Egg nebula is an AGB star, we conclude that such a common envelope phase must have lead to a merger, so the observed companion must have been a tertiary companion of a binary that merged at the time of nebula ejection. Based on the mass and timescale of the simulated disc formed around the companion before the common envelope phase, we analytically estimate the properties of jets that could be launched. Allowing for super-Eddington accretion rates, we find that jets similar to those observed are plausible, provided that the putative lost companion was relatively massive.Comment: accepted for publication in MNRA

Hydrodynamic simulations of the interaction between giant stars and planets

We present the results of hydrodynamic simulations of the interaction between a 10 Jupiter mass planet and a red or asymptotic giant branch stars, both with a zero-age main sequence mass of 3.5 M⊙. Dynamic in-spiral time-scales are of the order of few years and a few decades for the red and asymptotic giant branch stars, respectively. The planets will eventually be destroyed at a separation from the core of the giants smaller than the resolution of our simulations, either through evaporation or tidal disruption. As the planets in-spiral, the giant stars’ envelopes are somewhat puffed up. Based on relatively long time-scales and even considering the fact that further in-spiral should take place before the planets are destroyed, we predict that the merger would be difficult to observe, with only a relatively small, slow brightening. Very little mass is unbound in the process. These conclusions may change if the planet's orbit enhances the star's main pulsation modes. Based on the angular momentum transfer, we also suspect that this star–planet interaction may be unable to lead to large-scale outflows via the rotation-mediated dynamo effect of Nordhaus and Blackman. Detectable pollution from the destroyed planets would only result for the lightest, lowest metallicity stars. We furthermore find that in both simulations the planets move through the outer stellar envelopes at Mach-3 to Mach-5, reaching Mach-1 towards the end of the simulations. The gravitational drag force decreases and the in-spiral slows down at the sonic transition, as predicted analytically

Numerical evolution of multiple black holes with accurate initial data

We present numerical evolutions of three equal-mass black holes using the moving puncture approach. We calculate puncture initial data for three black holes solving the constraint equations by means of a high-order multigrid elliptic solver. Using these initial data, we show the results for three black hole evolutions with sixth-order waveform convergence. We compare results obtained with the BAM and AMSS-NCKU codes with previous results. The approximate analytic solution to the Hamiltonian constraint used in previous simulations of three black holes leads to different dynamics and waveforms. We present some numerical experiments showing the evolution of four black holes and the resulting gravitational waveform.Comment: Published in PR

Dynamic studies of 11Li and its core 9Li on 208Pb near the Coulomb barrier

We measured the scattering of the halo nucleus 11Li and its core 9Li on the lead target at TRIUMF at energies below and around to the Coulomb barrier. We report here on our preliminary analysis of the inclusive breakup reaction

Conjugated probiotics dispensed from birth to weaning for the survival of goat kids

a) Objective: To prevent morbidities, mortalities and increase weight gain and growth of kids by administering oral probiotic conjugate (PC). b) Design/Methodology/Approach: A randomized design comparing treatments (supplemented dose), percentage of morbidity and percentage of mortality. Goats were administered weekly from birth to 56 days of age. PC of Bifidobacterium bifidum essensis, Lactococcus lactis, Streptococcus thermophilus and Lactobacillus bulgaricus were dosed weekly. Treatments, TC: Control, T2: 2.0 mL PC/kg body weight (BW). T3: 3 mL PC/Kg BW. T4: 4 mL PC/Kg BW. c) Results: Diarrhea was present in: TC = 16%, T2 = 1%, T3 and T4 = 0% (TC vs. T2, T3, T4, P &lt;0.05). Mortality percentages: TC = 17%, T2, T3 and T4 = 0% (TC vs. T2, T3, T4, P &lt;0.05). T2 and T3 had an increase (P &lt;0.05) of 1.9 kg weight gain (WG) vs. TC. T3 was the best treatment at 56d (P &lt;0.05). d) Study Limitations/Implications: The doses used were defined based on other studies and experimental doses were used; the results consider that the facilities and management are optimal and in accordance with animal welfare standards. e) Findings/Conclusions: The most adequate dose was 1014 CFU/kg BW since it improved WG and reduced mortality. It is suggested to compare oral doses of probiotics to reduce death due to enteric diseases.To prevent morbidities, mortalities and increase weight gain and growth of kids by administering oral probiotic conjugate (PC). Design/Methodology/Approach: A randomized design comparing treatments (supplemented dose), percentage of morbidity and percentage of mortality.  Goats were administered weekly from birth to 56 days of age. PC of Bifidobacterium bifidum essensis, Lactococcus lactis, Streptococcus thermophilus and Lactobacillus bulgaricus were dosed weekly. Treatments, TC: Control, T2: 2.0 mL PC/kg body weight (BW). T3: 3 mL PC/Kg BW. T4: 4 mL PC/Kg BW. Results: Diarrhea was present in: TC = 16%, T2 = 1%, T3 and T4 = 0% (TC vs. T2, T3, T4, P &lt;0.05). Mortality percentages: TC = 17%, T2, T3 and T4 = 0% (TC vs. T2, T3, T4, P &lt;0.05). T2 and T3 had an increase (P &lt;0.05) of 1.9 kg weight gain (WG) vs. TC. T3 was the best treatment at 56d (P &lt;0.05). Study Limitations/Implications: The doses used were defined based on other studies and experimental doses were used; the results consider that the facilities and management are optimal and in accordance with animal welfare standards. Findings/Conclusions: The most adequate dose was 1014 CFU/kg BW since it improved WG and reduced mortality. It is suggested to compare oral doses of probiotics to reduce death due to enteric diseases

Evaluation of the consumption of two integral diets for psittacines in captivity in a wildlife rescue unit

Objective To evaluate the consumption of nutrient intake in a traditional diet and a proposed diet for parrots in captivity. Design/methodology/approach The study was carried out in Pachuca de Soto, Hidalgo, Mexico. Twelve parrots were used in captivity. The traditional diet (TD) provided to the birds was evaluated and a proposed diet (PA) was alternative. The consumption and the amount of waste of each diet were recorded for 5 weeks. PA was formulated with fruits, vegetables, and seeds. Data were analyzed by Student's t test to significance of 0.5. Results TD lacked homogeneity in the ingredients offered during the five weeks of study. There were significant differences in consumption between the 2 diets evaluated. The individual consumption of each bird was 349 g for TD and 314 g for PA. The TD had 41.87% was of fruits and 58.12% of vegetables. The PA included supplementation with seeds. From the second to the fifth week there was less waste in the PA. Limitations of the study The age, weight, sex and collection of excreta of the parrots were not registered, due to the restriction rules of the conservation area. Findings/conclusions The PA offered the requirements that parrots need. It is necessary to train technical personnel in the preparation of diets. Feeding frequencies and food diversity stimulated consumption and decreased waste, improving the nutritional balance of birds in captivity.Objective: To evaluate the consumption of nutrients intake in a traditional and aproposed diet for parrots in captivity.Design / methodology / approach: The study took place at Pachuca de Soto,Hidalgo, Mexico. Twelve parrots were assessed in captivity. The traditional diet(TD) provided to the birds was evaluated and a proposed diet (PD) was thealternative. The consumption and the amount of waste of each diet were recordedfor five weeks. PD formula contained fruits, vegetables, and seeds. Data wereanalyzed with the Student&amp;#39;s t-test at p&amp;lt; 0.5 significance.Results: TD lacked homogeneity in the ingredients offered during the five weeksevaluation. There were significant differences in the consumption between the two 2 evaluated diets. The individual bird consumption was 349 g for TD and 314 g forPD. The TD was 41.87% fruits and 58.12% vegetables. The PD diet includedseeds supplements. From the second to the fifth week of the evaluation PD hadless waste.Limitations of the study: The age, weight, sex and excreta collection from theparrots were not registered due to restriction rules in the conservation area.Findings / conclusions: The PD offered the requirements that parrots need. It isnecessary to train technical personnel on diet preparation. Feeding frequenciesand food diversity stimulated consumption and waste decreased, improving thenutritional balance of the birds in captivity

Coulomb dissociation of O-16 into He-4 and C-12

We measured the Coulomb dissociation of O-16 into He-4 and C-12 within the FAIR Phase-0 program at GSI Helmholtzzentrum fur Schwerionenforschung Darmstadt, Germany. From this we will extract the photon dissociation cross section O-16(alpha,gamma)C-12, which is the time reversed reaction to C-12(alpha,gamma)O-16. With this indirect method, we aim to improve on the accuracy of the experimental data at lower energies than measured so far. The expected low cross section for the Coulomb dissociation reaction and close magnetic rigidity of beam and fragments demand a high precision measurement. Hence, new detector systems were built and radical changes to the (RB)-B-3 setup were necessary to cope with the high-intensity O-16 beam. All tracking detectors were designed to let the unreacted O-16 ions pass, while detecting the C-12 and He-4