Results for "Aneta Wojnar"

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Equilibrium and stability of relativistic stars in extended theories of gravityApr 14 2016Jul 29 2016We study static, spherically symmetric equilibrium configurations in extended theories of gravity (ETG) following the notation introduced by Capozziello et {\it al}. We calculate the differential equations for the stellar structure in such theories in ... More
On the existence of static spherically-symmetric objects in action-dependent Lagrangian theoriesMar 28 2019We study static symmetric solutions in the context of a gravitational theory based on a action-dependent Lagrangian. Such theory has been designed as a setup to implement dissipative effects into the traditional principle of least action. Dissipation ... More
On stability of a neutron star system in Palatini gravityDec 05 2017May 16 2018We formulate the generalized Tolman-Oppenheimer-Volkoff equations for the $f(\hat{R})$ Palatini gravity in the case of static and spherical symmetric geometry. We also show that a neutron star is a stable system independently of the form of the functional ... More
Minimum main sequence mass in quadratic Palatini $f(\mathcal{R})$ gravityJun 11 2019General Relativity yields an analytical prediction of a minimum required mass of roughly $\sim 0.08-0.09 M_{\odot}$ for a star to stably burn sufficient hydrogen to fully compensate photospheric losses and, therefore, to belong to the main sequence. Those ... More
Polytropic stars in Palatini gravityAug 13 2018Jan 22 2019We have derived a modified Lane-Emden equation for the Starobinsky model in Palatini gravity which is numerically solvable. Comparing the results to the ones provided by General Relativity we observe a significant difference depending on the theory parameter ... More
Extended Theories of Gravity in cosmological and astrophysical applicationsOct 31 2016The main subjects of the PhD dissertation concern cosmological models considered in Palatini f(R) gravity and scalar-tensor theories. We introduce a simple generalization of the LCDM model based on Palatini modified gravity with quadratic Starobinsky ... More
Equilibrium and stability of relativistic stars in extended theories of gravityApr 14 2016Dec 11 2016We study static, spherically symmetric equilibrium configurations in extended theories of gravity (ETG) following the notation introduced by Capozziello et {\it al}. We calculate the differential equations for the stellar structure in such theories in ... More
Geometry of almost-product Lorentzian manifolds and relativistic observerFeb 07 2013Jun 27 2013The notion of relativistic observer is confronted with Naveira's classification of (pseudo-)Riemannian almost-product structures on space-time manifolds. Some physical properties and their geometrical counterparts are shortly discussed.
Dark matter influence on black hole objects thermodynamicsApr 05 2017Apr 25 2018Physical process version of the first law of black hole thermodynamics in Einstein- Maxwell dark matter gravity was derived. The dark matter sector is mimicked by the additional U(1)-gauge field coupled to the ordinary Maxwell one. By considering any ... More
Galaxy Rotation Curves via Conformal FactorsMay 11 2017Apr 11 2018We propose a new formula to explain circular velocity profiles of spiral galaxies obtained from the Starobinsky model in Palatini formalism. It is based on the assumption that the gravity can be described by two conformally related metrics: one of them ... More
A simple model for explaining Galaxy Rotation CurvesApr 25 2018A new simple expression for the circular velocity of spiral galaxies is proposed and tested against HI Nearby Galaxy Survey (THINGS) data set. Its accuracy is compared with the one coming from MOND.
A free parametrized TOV: Modified Gravity from Newtonian to Relativistic StarsJan 12 2016We test a free {\it ad hoc} parametrization of the Tolman-Oppenheimer-Volkoff (TOV) equation. We do not have in mind any specific extended theory of gravity (ETG) but each new parameter introduced has a physical interpretation. Our aim is fully pedagogical ... More
The average behaviour of financial market by 2 scale homogenisationAug 18 2006The financial market is nonpredictable, as according to the Bachelier, the mathematical expectation of the speculator is zero. Nevertheless, we observe in the price fluctuations the two distinct scales, short and long time. Behaviour of a market in long ... More
Do sewn singularities falsify the Palatini cosmology?Dec 10 2015Mar 20 2016We investigate further (cf. arXiv:1512.01199, JCAP01 (2016) 040) Starobinsky cosmological model $R+\gamma R^2$ in the Palatini formalism with Chaplygin gas and baryonic matter as a source. For this aim we use dynamical system theory. The dynamics is reduced ... More
Inflationary cosmology with Chaplygin gas in Palatini formalismDec 03 2015Jan 28 2016We present a simple generalisation of the $\Lambda$CDM model which on the one hand reaches very good agreement with the present day experimental data and provides an internal inflationary mechanism on the other hand. It is based on Palatini modified gravity ... More
The Palatini star: exact solutions of the modified Lane-Emden equationJan 29 2019Two exact solutions for $n=0$ and $n=1$ of the Palatini-modified Lane-Emden equation are found. We have employed these solutions to describe a Palatini-Newtonian neutron star and compared the result with the pure Newtonian counterpart. It turned out that ... More
X-ray emission from GPS and CSS sourcesJan 09 2009Many X-ray observations of GigaHertz Peaked Spectrum and Compact Steep Spectrum sources have been made with Chandra X-ray Observatory and XMM-Newton Observatory over the last few years. The X-ray spectra contribute the important information to the total ... More
Strangeness and bulk freeze-out properties at RHICOct 21 2007Identified charged kaon, pion, and proton spectra and ratios from sqrt(s_NN) = 200 and 62.4 GeV Cu+Cu collisions are studied with a hydro-motivated blast-wave and a statistical model framework in order to explore the strangeness production at RHIC and ... More
Universal Peculiar Linear Mean Relationships in All PolynomialsJun 08 2017Oct 23 2017In any cubic polynomial, the average of the slopes at the $3$ roots is the negation of the slope at the average of the roots. In any quartic, the average of the slopes at the $4$ roots is twice the negation of the slope at the average of the roots. We ... More
Groupoids and inverse semigroups associated to W*-algebrasOct 28 2011Feb 01 2012We investigate the Banach Lie groupoids and inverse semigroups naturally associated to W*-algebras. We also present statements describing relationship between these groupoids and the Banach Poisson geometry which follows in the canonical way from the ... More
Security of mobile agents: a new concept of the integrity protectionJun 29 2005The recent developments in the mobile technology (mobile phones, middleware) created a need for new methods of protecting the code transmitted through the network. The proposed mechanisms not only secure the compiled program, but also the data, that can ... More
Compactly Supported Cohomology Groups of Toric SurfacesMay 23 2015This article uses homological methods for evaluating compactly supported cohomology groups of noncompact toric surfaces
Invariant solutions and Noether symmetries in Hybrid GravityJul 16 2014Symmetries play a crucial role in physics and, in particular, the Noether symmetries are a useful tool both to select models motivated at a fundamental level, and to find exact solutions for specific Lagrangians. In this work, we consider the application ... More
Using the Additive Property of Compactly Supported Cohomology GroupsSep 05 2012This article uses basic homological methods for evaluating examples of compactly supported cohomology groups of line bundles over projective curve.
The long-term behavior of number of near-maximum insurance claimsApr 05 2019A near-maximum insurance claim is one falling within a distance $a$ of the current maximal claim. In this paper, we investigate asymptotic behavior of normalized numbers of near-maximum insurance claims under the assumption that the sequence of successive ... More
The incompressible limit of compressible finitely extensible nonlinear bead-spring chain models for dilute polymeric fluidsJun 11 2019We explore the behaviour of global-in-time weak solutions to a class of bead-spring chain models, with finitely extensible nonlinear elastic (FENE) spring potentials, for dilute polymeric fluids. In the models under consideration the solvent is assumed ... More
Unsteady flows of heat-conducting non-Newtonian fluids in~Musielak-Orlicz spacesNov 16 2015Our purpose is to show the existence of weak solutions for unsteady flow of non-Newtonian incompressible nonhomogeneous, heat-conducting fluids with generalised form of the stress tensor without any restriction on its upper growth. Motivated by fluids ... More
Wheeler-DeWitt equation and Lie symmetries in Bianchi scalar-field cosmologyJan 25 2016Lie symmetries are discussed for the Wheeler-De Witt equation in Bianchi Class A cosmologies. In particular, we consider General Relativity, minimally coupled scalar field gravity and Hybrid Gravity as paradigmatic examples of the approach. Several invariant ... More
Nonautonomous driving induces stability in network of identical oscillatorsSep 13 2018Nonautonomous driving of an oscillator has been shown to enlarge the Arnold tongue in parameter space, but little is known about the analogous effect for a network of oscillators. To test the hypothesis that deterministic nonautonomous perturbation is ... More
Design of engineering systems in Polish mines in the third quarter of the 20th centuryMar 30 2018Participation of mathematicians in the implementation of economic projects in Poland, in which mathematics-based methods played an important role, happened sporadically in the past. Usually methods known from publications and verified were adapted to ... More
A family of integrable perturbed Kepler systemsJan 13 2019Jan 18 2019In the framework of the Poisson geometry of twistor space we consider a family of perturbed 3-dimensional Kepler systems. We show that Hamilton equations of this systems are integrated by quadratures. Their solutions for some subcases are given explicitly ... More
Quasi-random Agents for Image Transition and AnimationOct 20 2017Quasi-random walks show similar features as standard random walks, but with much less randomness. We utilize this established model from discrete mathematics and show how agents carrying out quasi-random walks can be used for image transition and animation. ... More
Evolution of Images with Diversity and Constraints Using a Generator NetworkFeb 15 2018Evolutionary search has been extensively used to generate artistic images. Raw images have high dimensionality which makes a direct search for an image challenging. In previous work this problem has been addressed by using compact symbolic encodings or ... More
Evolutionary Image Transition Based on Theoretical Insights of Random ProcessesApr 21 2016Evolutionary algorithms have been widely studied from a theoretical perspective. In particular, the area of runtime analysis has contributed significantly to a theoretical understanding and provided insights into the working behaviour of these algorithms. ... More
Poisson geometry related to Atiyah sequencesJun 10 2015We construct and investigate a short exact sequence of Poisson VB-groupoids which is canonically related to the Atiyah sequence of a G-principal bundle P. Our results include a description of the structure of the symplectic leaves of the Poisson groupoid ... More
Stabilisation of dynamics of oscillatory systems by non-autonomous perturbationMar 30 2018Synchronisation and stability under periodic oscillatory driving are well-understood, but little is known about the effects of aperiodic driving, despite its abundance in nature. Here, we consider oscillators subject to driving with slowly varying frequency, ... More
Limitations of the asymptotic approach to dynamicsOct 09 2018Standard dynamical systems theory is centred around the coordinate-invariant asymptotic-time properties of autonomous systems. We identify three limitations of this approach. Firstly, we discuss how the traditional approach cannot take into account the ... More
Trollslayer: Crowdsourcing and Characterization of Abusive Birds in TwitterDec 14 2018As of today, abuse is a pressing issue to participants and administrators of Online Social Networks (OSN). Abuse in Twitter can spawn from arguments generated for influencing outcomes of a political election, the use of bots to automatically spread misinformation, ... More
The Evolutionary Process of Image Transition in Conjunction with Box and Strip MutationAug 05 2016Evolutionary algorithms have been used in many ways to generate digital art. We study how evolutionary processes are used for evolutionary art and present a new approach to the transition of images. Our main idea is to define evolutionary processes for ... More
Fibre-wise linear Poisson structures related to W*-algebrasMar 03 2017In this paper we investigate fiber-wise linear complex Banach sub-Poisson structures defined canonically by the structure of a W*-algebra M. In particular we show that these structures are arranged in the short exact sequence of complex Banach sub-Poisson ... More
Radiation pressure instability driven variability in the accreting black holesMay 15 2002The time dependent evolution of the accretion disk around black hole is computed. The classical description of the $\alpha$-viscosity is adopted so the evolution is driven by the instability operating in the innermost radiation-pressure dominated part ... More
Algebroids associated to the groupoid of partially invertible elements of a $W^*$-algebraJan 04 2014In the paper we study the algebroid A of the groupoid of partially invertible elements over the lattice of orthogonal projections of a $W^*$-algebra. In particular the complex analytic manifold structure of these objects is investigated. The expressions ... More
Efficient distribution and improved security for reliable cloud storage systemFeb 05 2016The distributed data storage systems are constructed by large number of nodes which are interconnected over a network. Each node in such peer-to-peer network is vulnerable and at a potential risk for attack. The attackers can eavesdrop the nodes and possibly ... More
Radiation pressure instability as a variability mechanism in the microquasar GRS 1915+105Aug 23 2000Physical mechanism responsible for high viscosity in accretion disks is still under debate. Parameterization of the viscous stress as $\alpha P$ proved to be a successful representation of this mechanism in the outer parts of the disk, explaining the ... More
Symmetries of the space of connections on a principal G-bundle and related symplectic structuresDec 22 2017We investigate G-invariant symplectic structures on the cotangent bundle T*P of a principal G-bundle P(M,G) which are canonically related to automorphisms of the tangent bundle TP covering the identity map of P and commuting with the action of TG on TP. ... More
Poisson Geometry Related to Atiyah SequencesJun 10 2015Jan 10 2018We construct and investigate a short exact sequence of Poisson $\mathcal{VB}$-groupoids which is canonically related to the Atiyah sequence of a $G$-principal bundle $P$. Our results include a description of the structure of the symplectic leaves of the ... More
Magnetic-field-induced abrupt spin state transition in a quantum dot containing magnetic ionsAug 22 2016We present the results of a comprehensive magneto-optical characterization of single CdTe quantum dots containing a few Mn2+ ions. We find that some quantum dots exhibit an unexpected evolution of excitonic photoluminescence spectrum with the magnetic ... More
Heavy-Ion Physics with CMSJun 06 2008This article presents a brief overview of the CMS experiment capabilities to study the hot and dense matter created in relativistic heavy-ion collisions. The CERN Large Hadron Collider will provide collisions of Pb nuclei at 5.5 TeV per nucleon. The CMS ... More
Neuronal synchrony during anaesthesia - A thalamocortical modelOct 29 2008There is growing evidence in favour of the temporal-coding hypothesis that temporal correlation of neuronal discharges may serve to bind distributed neuronal activity into unique representations and, in particular, that $\theta$ (3.5-7.5 Hz) and $\delta$ ... More
Origin of the complex radio structure in BAL QSO 1045+352Jul 08 2010We present new more sensitive high-resolution radio observations of a compact broad absorption line (BAL) quasar, 1045+352, made with the EVN+MERLIN at 5 GHz. They allowed us to trace the connection between the arcsecond structure and the radio core of ... More
Optical signatures of spin dependent coupling in semimagnetic quantum dot moleculesFeb 12 2015We present photoluminescence studies of CdTe and CdMnTe quantum dots grown in two adjacent layers. We show that when the dots are 8 nm apart, their magnetooptical properties - Zeeman shifts and transition linewidths - are analogous to those of individual ... More
Introducing single Mn2+ ions into spontaneously coupled quantum dot pairsOct 12 2013We present the photoluminescence excitation study of the self-assembled CdTe/ZnTe quantum dots doped with manganese ions. We demonstrate the identification method of spontaneously coupled quantum dots pairs containing single Mn2+ ions. As the result of ... More
Optically induced energy and spin transfer in non-resonantly coupled pairs of self-assembled CdTe/ZnTe quantum dotsAug 12 2008Asymmetrical horizontal interdot coupling was demonstrated to exist in a system of a single plane of self-assembled CdTe/ZnTe quantum dots. Photoluminescence excitation (PLE), second order photon correlation and optical orientation were used as main experimental ... More
Models of Accretion DisksMar 06 2012An accretion flow onto a supermassive black hole is the primary process powering quasars. However, a geometry of this flow is not well constrained. Both global MHD simulations and observations suggest that there are several emission components present ... More
sl(2,R) symmetry and solvable multiboson systemsAug 08 2006Sep 20 2006The one-mode and the two-mode multiboson systems with sl(2,R) symmetry are investigated.Hamiltonians of these systems are integrated using the theory of orthogonal polynomials. The coherent state representation for these systems is constructed.
Division of the Energy Market into Zones in Variable Weather Conditions using Locational Marginal PricesOct 18 2013Adopting a zonal structure of electricity market requires specification of zones' borders. One of the approaches to identify zones is based on clustering of Locational Marginal Prices (LMP). The purpose of the paper is twofold: (i) we extend the LMP methodology ... More
Probing the accretion disk - jet connection via instabilities in the inner accretion flow. From microquasars to quasarsOct 05 2010We present various instability mechanisms in the accreting black hole systems which might indicate at the connection between the accretion disk and jet. The jets observed in microquasars can have a persistent or blobby morphology. Correlated with the ... More
Variability Model for the Microquasar GRS 1915+105Apr 25 2000We analyse the radiation pressure instability of the standard, optically thisc disc and propose it as an explanation of the obseved variability of the superluminal microquasar GRS 1915+105. The quantitave agreement with the observed outburst amplitudes ... More
On long-time asymptotics for viscous hydrodynamic models of collective behavior with damping and nonlocal interactionsSep 27 2017Mar 08 2018Hydrodynamic systems arising in swarming modelling include nonlocal forces in the form of attractive-repulsive potentials as well as pressure terms modelling strong local repulsion. We focus on the case where there is a balance between nonlocal attraction ... More
Coupling functions: Universal insights into dynamical interaction mechanismsJun 05 2017Nov 14 2017The dynamical systems found in Nature are rarely isolated. Instead they interact and influence each other. The coupling functions that connect them contain detailed information about the functional mechanisms underlying the interactions and prescribe ... More
Searching for Narrow Emission Lines in X-ray Spectra: Computation and MethodsAug 23 2008The detection and quantification of narrow emission lines in X-ray spectra is a challenging statistical task. The Poisson nature of the photon counts leads to local random fluctuations in the observed spectrum that often results in excess emission in ... More
Weak solutions to the full Navier-Stokes-Fourier system with slip boundary conditions in time dependent domainsNov 16 2015We consider the compressible Navier-Stokes-Fourier system on time-dependent domains with prescribed motion of the boundary, supplemented with slip boundary conditions for the velocity. Assuming that the pressure can be decomposed into an elastic part ... More
Evolutionary Algorithms for the Chance-Constrained Knapsack ProblemFeb 13 2019Evolutionary algorithms have been widely used for a range of stochastic optimization problems. In most studies, the goal is to optimize the expected quality of the solution. Motivated by real-world problems where constraint violations have extremely disruptive ... More
Evolutionary Diversity Optimization Using Multi-Objective IndicatorsNov 16 2018Evolutionary diversity optimization aims to compute a diverse set of solutions where all solutions meet a given quality criterion. With this paper, we bridge the areas of evolutionary diversity optimization and evolutionary multi-objective optimization. ... More
Linear and synchrosqueezed time-frequency representations revisited. Part II: Resolution, reconstruction and concentrationOct 27 2013May 26 2014Having reviewed the aspects of the linear and synchrosqueezed time-frequency representations (TFRs) needed for their understanding and correct use in Part I of this review, we now consider three more subtle issues that are nonetheless of crucial importance ... More
Glassy states and superrelaxation in populations of coupled phase oscillatorsMar 18 2013Oct 28 2013Large networks of coupled oscillators appear in many branches of science, so that the kinds of phenomena they exhibit are not only of intrinsic interest but also of very wide importance. In 1975, Kuramoto proposed an analytically tractable model to describe ... More
Mean Field and Mean Ensemble Frequencies of a System of Coupled OscillatorsFeb 28 2013We investigate interacting phase oscillators whose mean field is at a different frequency from the mean or mode of their natural frequencies. The associated asymmetries lead to a macroscopic travelling wave. We show that the mean ensemble frequency of ... More
Inference of Time-Evolving Coupled Dynamical Systems in the Presence of NoiseJun 09 2012Jun 24 2012A new method is introduced for analysis of interactions between time-dependent coupled oscillators, based on the signals they generate. It distinguishes unsynchronized dynamics from noise-induced phase slips, and enables the evolution of the coupling ... More
Pareto Optimization for Subset Selection with Dynamic Cost ConstraintsNov 14 2018In this paper, we consider the subset selection problem for function $f$ with constraint bound $B$ which changes over time. We point out that adaptive variants of greedy approaches commonly used in the area of submodular optimization are not able to maintain ... More
Discrepancy-based Evolutionary Diversity OptimizationFeb 15 2018Diversity plays a crucial role in evolutionary computation. While diversity has been mainly used to prevent the population of an evolutionary algorithm from premature convergence, the use of evolutionary algorithms to obtain a diverse set of solutions ... More
Coherent precession of an individual 5/2 spinAug 10 2014We present a direct observation of a coherent spin precession of an individual Mn$^{2+}$ ion, having both electronic and nuclear spins equal to 5/2, embedded in a CdTe quantum dot and placed in magnetic field. The spin state evolution is probed in a time-resolved ... More
Dynamics of Charge Leakage From Self-assembled CdTe Quantum DotsMar 31 2010We study the leakage dynamics of charge stored in an ensemble of CdTe quantum dots embedded in a field-effect structure. Optically excited electrons are stored and read out by a proper time sequence of bias pulses. We monitor the dynamics of electron ... More
Engineering the hole confinement for CdTe-based quantum dot moleculesFeb 12 2015We demonstrate an efficient method to engineer the quantum confinement in a system of two quantum dots grown in a vertical stack. We achieve this by using materials with a different lattice constant for the growth of the outer and inner barriers. We monitor ... More
Anisotropy of in-plane hole g-factor in CdTe/ZnTe quantum dotsApr 09 2016Optical studies of a bright exciton provide only limited information about the hole anisotropy in a quantum dot. In this work we present a universal method to study heavy hole anisotropy using a dark exciton in a moderate in-plane magnetic field. By analysis ... More
Picosecond charge variation of quantum dots under pulsed excitationNov 17 2009We present a spectroscopic study of excitation dynamics in self assembled CdTe/ZnTe quantum dots. Insight into details of kinetics is obtained from the time resolved micro-photoluminescence, single photon correlation and subpicosecond excitation correlation ... More
On the turbulent $α$-disks and the intermittent activity in AGNNov 01 2003We consider effects of the MHD turbulence on the viscosity during the evolution of the thermal-viscous ionization instability in the standard $\alpha$-accretion disks. We consider the possibility that the accretion onto a supermassive black hole proceeds ... More
Pressureless Euler with nonlocal interactions as a singular limit of degenerate Navier-Stokes systemJun 03 2019We show that weak solutions of degenerate Navier-Stokes equations converge to the strong solutions of the pressureless Euler system with linear drag term, Newtonian repulsion and quadratic confinement. The proof is based on the relative entropy method ... More
Evolutionary Image Composition Using Feature Covariance MatricesMar 10 2017Evolutionary algorithms have recently been used to create a wide range of artistic work. In this paper, we propose a new approach for the composition of new images from existing ones, that retain some salient features of the original images. We introduce ... More
Optical study of electron-electron exchange interaction in CdTe/ZnTe quantum dotsApr 22 2013We present an experimental study of electron-electron exchange interaction in self-assembled CdTe/ZnTe quantum dots based on the photoluminescence measurements. The character and strength of this interaction are obtained by simultaneous observation of ... More
Quantum interference in exciton-Mn spin interactions in a CdTe semiconductor quantum dotMay 04 2011We show theoretically and experimentally the existence of a new quantum interference(QI) effect between the electron-hole interactions and the scattering by a single Mn impurity. Theoretical model, including electron-valence hole correlations, the short ... More
Brightening of dark excitons in a single quantum dot containing a single magnetic ionJun 08 2010A promising method to investigate dark exciton transitions in quantum dots is presented. The optical recombination of the dark exciton is allowed when the exciton state is coupled with an individual magnetic impurity (manganese ion). It is shown that ... More
Optical manipulation of a single Mn spin in a CdTe-based quantum dotNov 18 2008A system of two coupled CdTe quantum dots, one of them containing a single Mn ion, was studied in continuous wave and modulated photoluminescence, photoluminescence excitation, and photon correlation experiments. Optical writing of information in the ... More
Manipulating the exciton fine structure of single CdTe/ZnTe quantum dots by an in-plane magnetic fieldOct 11 2006Polarization resolved photoluminescence (PL) spectroscopy of individual CdTe/ZnTe quantum dots is investigated in the presence of external in-plane magnetic field. We find that the excitonic fine structure strongly depends on the magnitude and direction ... More
Inter-shell exchange interaction in CdTe/ZnTe quantum dots: magneto-photoluminescence of X, X2- and XX-Jun 27 2011We present a comprehensive photoluminescence study of exchange interaction in self-assembled CdTe/ZnTe quantum dots. We exploit the presence of multiple charge states in the photoluminescence spectra of single quantum dots to analyze simultaneously fine ... More
In-plane radiative recombination channel of a dark exciton in self-assembled quantum dotsJul 05 2012Jan 03 2013We demonstrate evidence for a radiative recombination channel of dark excitons in self-assembled quantum dots. This channel is due to a light hole admixture in the excitonic ground state. Its presence was experimentally confirmed by a direct observation ... More
150 keV Emission from PKS2149-306 with BeppoSAXJun 16 2000Jul 24 2001A BeppoSAX observation of the z=2.34 quasar PKS2149-306 produced a strong signal in the high energy PDS instrument up to a maximum observed energy of nearly 50 keV, 150 keV in the quasar frame. The Beppo-SAX spectrum spans almost 3 decades (0.3-150 keV, ... More
The Impact of the Environment on the Early Stages of Radio Source EvolutionDec 05 2018Compact Symmetric Objects (CSOs) show radio features such as jets, lobes, hot spots that are contained within the central 1 kpc region of their host galaxy. Thus, they are thought to be among the progenitors of large-scale radio galaxies. A debate on ... More
Asymmetry--induced effects in coupled phase oscillator ensembles: Routes to synchronizationApr 15 2009A system of two coupled ensembles of phase oscillators can follow different routes to inter-ensemble synchronization. Following a short report of our preliminary results [Phys. Rev. E. {\bf 78}, 025201(R) (2008)], we present a more detailed study of the ... More
Bayesian Estimates of Astronomical Time Delays between Gravitationally Lensed Stochastic Light CurvesFeb 03 2016Jan 30 2017The gravitational field of a galaxy can act as a lens and deflect the light emitted by a more distant object such as a quasar. Strong gravitational lensing causes multiple images of the same quasar to appear in the sky. Since the light in each gravitationally ... More
A strong ergodic theorem for extreme and intermediate order statisticsApr 27 2017We study almost sure limiting behavior of extreme and intermediate order statistics arising from strictly stationary sequences. First, we provide sufficient dependence conditions under which these order statistics converges almost surely to the left or ... More
On the key exchange with nonlinear polynomial maps of stable degreeApr 10 2013We say that the sequence $g_n$, $n\ge 3$, $n \rightarrow \infty$ of polynomial transformation bijective maps of free module $K^n$ over commutative ring $K$ is a sequence of stable degree if the order of $g_n$ is growing with $n$ and the degree of each ... More
Routes to synchrony between asymmetrically interacting oscillator ensemblesOct 24 2008We report that asymmetrically interacting ensembles of oscillators (AIEOs) follow novel routes to synchrony. These routes seem to be a characteristic feature of coupling asymmetry. We show that they are unaffected by white noise except that the entrainment ... More
MDFS - MultiDimensional Feature SelectionOct 31 2018Identification of informative variables in an information system is often performed using simple one-dimensional filtering procedures that discard information about interactions between variables. Such approach may result in removing some relevant variables ... More
Correlation between X-ray and radio absorption in compact radio galaxiesSep 25 2017Oct 30 2017Compact radio galaxies with a GHz-peaked spectrum (GPS) and/or compact-symmetric-object (CSO) morphology (GPS/CSOs) are increasingly detected in the X-ray domain. Their radio and X-ray emissions are affected by significant absorption. However, the locations ... More
Intermittent Activity of Jets in AGNFeb 27 2010Large scale X-ray jets that extend to >100 kpc distances from the host galaxy indicate the importance of jets interactions with the environment on many different physical scales. Morphology of X-ray clusters indicate that the radio-jet activity of a cD ... More
Bayesian Estimates of Astronomical Time Delays between Gravitationally Lensed Stochastic Light CurvesFeb 03 2016The gravitational field of a galaxy can act as a lens and deflect the light emitted by a more distant object such as a quasar. If the galaxy is a strong gravitational lens, it can produce multiple images of the same quasar in the sky. Since the light ... More
Detecting Unspecified Structure in Low-Count ImagesOct 15 2015Unexpected structure in images of astronomical sources often presents itself upon visual inspection of the image, but such apparent structure may either correspond to true features in the source or be due to noise in the data. This paper presents a method ... More
Interplay between couplings and common noise in phase synchronization: disagreement between global analysis and local stability characterizationSep 14 2008Nov 19 2008We consider two coupled phase oscillators in the presence of proportional ("common") and independent white noises. The global synchronization properties of the system are analytically studied via the Fokker-Planck equation. When the "effective coupling" ... More
An X-ray jet discovered by Chandra in the z=4.3 radio-selected quasar GB 1508+5714Oct 09 2003We report the Chandra discovery of an X-ray jet associated with the redshift 4.3 radio-loud quasar GB 1508+5714. The jet X-ray emission peaks ~2 arcsec to the South-West of the quasar core. We present archival HST WFPC2 data of the quasar field which ... More
Chandra Discovery of a 300 kpc X-ray Jet in the GPS Quasar PKS1127-145Jan 08 2002We have discovered an X-ray jet with Chandra imaging of the z=1.187 radio-loud quasar PKS1127-145. In this paper we present the Chandra X-ray data, follow-up VLA observations, and optical imaging using the HST WFPC2. The X-ray jet contains 273+/-5 net ... More