May 2005 arXiv papers — page 7

V. V. Begun, M. I. Gorenstein, A. P. Kostyuk, O. S. Zozulya

A new method is proposed for a treatment of ideal quantum gases in the microcanonical ensemble near the thermodynamic limit. The method allows rigorous asymptotic calculations of the average number of particles and particle number fluctuations in the microcanonical ensemble. It gives also the finite-volume corrections due to exact energy conservation for the

Mario A. Acero, Maurizio De Sanctis, Carlos E. Sandoval

We present a procedure to derive a covariant electromagnetic current operator for a system made up by two scalars constituents. Using different wave functions we fitted their parameters to the experimental data of the pion form factor, obtainig great discrepancy at low momentum transfer. Introducing the Vector Meson Dominance corrective factor, we obtained a

Y. K. Gambhir, A. Bhagwat, M. Gupta

The results of extensive microscopic Relativistic Mean Field (RMF) calculations for the nuclei appearing in the alpha - decay chains of recently discovered superheavy elements with Z = 109 to 118 are presented and discussed. The calculated ground state properties like total binding energies, Q values, deformations, radii and densities closely agree with the

Metin Gurses, Kostyantyn Zheltukhin

A transforation between a hierarchy of integrable equations arising from the standard $R$-matrix construction on the algebra of differential operators and a hierarchy of integrable equations arising from a deformation of the standard $R$-matrix is given.

Tetsu Yajima, Keisuke Nakajima, Naruyoshi Asano

A generalization of the max-plus transformation, which is known as a method to derive cellular automata from integrable equations, is proposed for complex numbers. Operation rules for this transformation is also studied for general number of complex variables. As an application, the max-plus transformation is applied to the discrete Fourier transformation. S

A. G. Munoz, J. Ojeda, D. Sierra, T. Soldovieri

There is recent interest in finding a potential formulation for Stochastic Partial Differential Equations (SPDEs). The rationale behind this idea lies in obtaining all the dynamical information of the system under study from one single expression. In this Letter we formally provide a general Lagrangian formalism for SPDEs using the Hojman et al. method. We s

A. B. Balantekin, T. Dereli, Y. Pehlivan

Three well-known solutions of the Gaudin equation are obtained under a set of standard assumptions. By relaxing one of these assumptions we introduce a class of mutually commuting Hamiltonians based on a different solution of the Gaudin equation. Application of the algebraic Bethe ansatz technique to diagonalize these Hamiltonians reveals a new infinite dime

Attila B. von Keviczky, Nasser Saad, Richard L. Hall

Summation formulas are obtained for products of associated Lagurre polynomials by means of the Green's function K for the Hamiltonian H = -{d^2\over dx^2} + x^2 + Ax^{-2}, A > 0. K is constructed by an application of a Mercer type theorem that arises in connection with integral equations. The new approach introduced in this paper may be useful for the co

Hakan Ciftci, Richard L. Hall, Nasser Saad

We consider a single particle which is bound by a central potential and obeys the Dirac equation in d dimensions. We first apply the asymptotic iteration method to recover the known exact solutions for the pure Coulomb case. For a screened-Coulomb potential and for a Coulomb plus linear potential with linear scalar confinement, the method is used to obtain a

Jochen Bruening, Vladimir Geyler, Konstantin Pankrashkin

We investigate the behavior of the Green functions of Schroedinger operators near the diagonal. The only non-trivial cases, where the on-diagonal singularities are non-zero and do not depend on the spectral parameter, are two and three dimensions. In the case of two dimensions, we show that the singularity is independent of both the scalar and the gauge pote

Olivier Ripoll

Nous donnons un procede explicite de determination du rang d'un d-tissu non singulier du plan quelconque a l'aide de sa connexion associee. Une etude de quelques invariants du tissu est egalement proposee. We give an explicit process of determination of the rank of any non singular planar d-web thanks to its associated connection. A study of some inv

Bruno Harris

We use the heat kernel (on differential forms) on a compact Riemannian manifold to assign a real number to a k-tuple of cycles on the manifold satisfying certain conditions. If k is 2, this number is the ordinary topological linking number, an integer but if k is at least 3 the number is real and depends on the metric. We study how the number changes if the

Max-K. von Renesse

It is shown that curvature-dimension bounds CD(N, k) for a metric measure space (X,d,m) in the sense of Sturm imply a weak L^1- Poincare-inequality under some symmetry assumption on the choice of transport rays in the cut locus of (X,d). This condition is satisfied if (X,d) has m-almost surely no branching points.

Zhiqin Lu

In this paper, we compute the Tian-Zhu invariant on hypersurfaces of complex projective spaces.

Zhiqin Lu

In this paper, we proved a rigidity theorem of the Hodge metric for concave horizontal slices and a local rigidity theorem for the monodromy representation.

Zhiqin Lu

The paper is related to the classification of special manifolds and projective special manifolds. One of the result of this paper is that, if the Weil-Petersson metric on a projective special manifold is complete, then the Hodge metrc and the Weil-Petersson metrc are equivalent.

Zhiqin Lu

In this paper, we represent the Hodge metric in terms of the Weil-Petersson metric and its Ricci curvature on the moduli spaces of polarized Calabi-Yau threefolds.

Silvano Baggio

We present a short proof of Reisner's Theorem, characterizing which simplicial complexes have a Cohen-Macaulay face ring. In some cases, we can also express some homological invariants of the face ring in terms of the reduced homology of the complex.

Zhiqin Lu

In this paper, we prove a result related to the deformation of complex submanifolds, modifying a result of Kodaira (Ann. Math, 75(1), 146-162, 1962).

Zhiqin Lu

In this paper, we study the local properties of the moduli space of a polarized Calabi-Yau manifold. Let $U$ be a neighborhood of the moduli space. Then we know the universal covering space $V$ of $U$ is a smooth manifold. Suppose $D$ is the classifying space of a polarized Calabi-Yau manifold with the automorphism group $G$. Let $D_1$ be the symmetric space

Zhiqin Lu

In this paper, we give an explicit formula for the Futaki invariants of complete intersections. The result is new in the case where the variety is smooth or has orbifold singularities.

Zhiqin Lu

We proved a conjecture of D. Freed that there are no non-trivial complete special Kaehler manifolds.

Jianguo Cao, Huijun Fan, Francois Ledrappier

The Martin boundary of a Cartan-Hadamard manifold describes a fine geometric structure at infinity, which is a sub-space of positive harmonic functions. We describe conditions which ensure that some points of the sphere at infinity belong to the Martin boundary as well. In the case of the universal cover of a compact manifold with Ballmann rank one, we show

Terrence Napier, Mohan Ramachandran

The purpose of this note is to prove that Richard Thompson's group F and variants of it studied by Ken Brown are not Kahler groups.

A. A. Dorogovtsev

The random measures on the space of continuous functions are considered. Stationary random measures are described. The weak solutions of the stochastic equations are substituted by the strong measure-valued solutions.

Marc De Crisenoy, Driss Essouabri

We give a new and very concise proof of the existence of a holomorphic continuation for a large class of twisted multivariable zeta functions. To do this, we use a simple method of "decalage" that avoids using an integral representation of the zeta function. This allows us to derive explicit recurrence {\it relations} between the values at $T-$tuples

Armando Martino

We prove that the fundamental group of any Seifert 3-manifold is conjugacy separable. That is, conjugates may be distinguished in finite quotients or, equivalently, conjugacy classes are closed in the pro-finite topology.

Gregory Eskin

We study the inverse boundary value problems for the Schrödinger equations with Yang-Mills potentials in a bounded domain $Ω_0\subset\R^n$ containing finite number of smooth obstacles $Ω_j,1\leq j \leq r$. We prove that the Dirichlet-to-Neumann operator on $\partialΩ_0$ determines the gauge equivalence class of the Yang-Mills potentials. We also prove that t

Raphael Cerf, Sana Louhichi

We consider the 2D stochastic Ising model evolving according to the Glauber dynamics at zero temperature. We compute the initial drift for droplets which are suitable approximations of smooth domains. A specific spatial average of the derivative at time~0 of the volume variation of a droplet close to a boundary point is equal to its curvature multiplied by a

Stavros Garoufalidis, Thang TQ. Le, Doron Zeilberger

We state and prove a quantum-generalization of MacMahon's celebrated Master Theorem, and relate it to a quantum-generalization of the boson-fermion correspondence of Physics.

Pau Figueras

We present a solution of the vacuum Einstein's equations in five dimensions corresponding to a black ring with horizon topology S^1 x S^2 and rotation in the azimuthal direction of the S^2. This solution has a regular horizon up to a conical singularity, which can be placed either inside the ring or at infinity. This singularity arises due to the fact th

Alice Rogers

The supersymmetric model developed by Witten to study the equivariant cohomology of a manifold with an isometric circle action is derived from the BRST quantization of a simple classical model. The gauge-fixing process is carefully analysed, and demonstrates that different choices of gauge-fixing fermion can lead to different quantum theories.

C. Klimcik

We identify the obstructions for T-dualizing the boundary WZW model and make explicit how they depend on the geometry of branes. In particular, the obstructions disappear for certain brane configurations associated to non-regular elements of the Cartan torus. It is shown in this case that the boundary WZW model is "nested" in the twisted boundary WZW

E. Buffenoir, Ph. Roche

We study the quantization of Chern-Simons theory with group $G$ coupled to dynamical sources. We first study the dynamics of Chern-Simons sources in the Hamiltonian framework. The gauge group of this system is reduced to the Cartan subgroup of $G.$ We show that the Dirac bracket between the basic dynamical variables can be expressed in term of dynamical $r-$

Rajsekhar Bhattacharyya

Here we try to construct a form of multi-bion solution in the dual description of $D3 \bot D1$-system which connects the two separated bions each made up of 2 $D1-branes$ at large distance with a single $D3$-brane of four unit of magnetic charge at origin. Further we interested in the soluions which can interpolate between arbitrarily separated bions and sin

Yoshinobu Habara, Holger B. Nielsen, Masao Ninomiya

We propose a hole theory for bosons, in which, analogous to fermions, a hole produced by the annihilation of one negative energy boson is an anti-particle. We show that the boson vacuum indeed also consists of a sea in which all negative energy states are filled and the density of probability of the Klein-Gordon theory is positive definite also for the negat

L. P. Csernai, V. K. Magas, E. Molnar, A. Nyiri

We study Freeze Out process in high energy heavy ion reaction. The description of the process is based on the Boltzmann Transport Equation (BTE). We point out the basic limitations of the BTE approach and introduce Modified BTE. The Freeze Out dynamics is presented in the 4-dimensional space-time in a layer of finite thickness, and we employ Modified BTE for

Howard Baer, Azar Mustafayev, Eun-Kyung Park, Stefano Profumo

In supersymmetric models with gravity-mediated SUSY breaking and gaugino mass unification, the predicted relic abundance of neutralinos usually exceeds the strict limits imposed by the WMAP collaboration. One way to obtain the correct relic abundance is to abandon gaugino mass universality and allow a mixed wino-bino lightest SUSY particle (LSP). The enhance

Elena Accomando, Alessandro Ballestrero, Aissa Belhouari, Ezio Maina

We analyse some features of WW scattering processes at LHC. The severe cancellations between fusion diagrams and the other contributions evidence the necessity of complete calculations for studying the high WW invariant mass region and disentangling the standard Higgs case from new physics.

Vittorio Lubicz

Recent experimental and theoretical results on kaon semileptonic decays have significantly improved the determination of the CKM matrix element V_us. After briefly summarizing the impact of the new experimental determinations, I will concentrate in this talk on the theoretical progresses, coming in particular from lattice QCD calculations. These results lead

Gilad Perez, Tomer Volansky

A new scenario of baryogenesis is presented, within the split fermions framework. Our model employs a first order phase transition of the localizer field. The standard model (SM), Kobayashi-Maskawa phase induces a sizable CP asymmetry. The usual suppression of CP violation which arises in the SM baryogenesis is absent due to the existence of order one Yukawa

Jiao Lin Xu

Using an expanded form of Planck-Bohr's quantization method and phenomenological formulae,} {\small we deduce the rest masses and intrinsic quantum numbers (I, S, C, b and Q) of all kinds of the lowest energy quarks and baryons, from only one elementary quark family}$ε$ {\small with S = C = b = 0. The deduced quantum numbers match those found in experime

Tomohiro Matsuda

This paper has been withdrawn by the author(s), due the following reasons. A similar system for a different purpose has already been studied in Phys.Rev.D60:083001,1999 (astro-ph/9904315). Moreover, our analysis was wrong because we have missed the large frictional forces that will rapidly damp out the energy in the oscillating monopolonium system.

Francis Bursa, Michael Teper

We perform lattice calculations of the spatial 't Hooft k-string tensions in the deconfined phase of SU(N) gauge theories for N=2,3,4,6. These equal (up to a factor of T) the surface tensions of the domain walls between the corresponding (Euclidean) deconfined phases. For T much larger than Tc our results match on to the known perturbative result, which

Trevor Vickey

The most recent results on top quark physics at CDF are reported. Measurements of cross-section and mass are presented, and the status of single top quark production searches are discussed. The results obtained from probing various top quark properties are also presented.

The BABAR Collaboration, B. Aubert

We report the observation of the decay $B^- \to D_{π^+π^-π^0} K^-$, where $D_{π^+π^-π^0}$ indicates a neutral $D$ meson detected in the final state $π^+π^-π^0$, excluding $K_S π^0$. This doubly Cabibbo-suppressed decay chain can be used to measure the CKM phase $γ$. Using about 229 million $e^+e^- \to B \bar B$ events recorded by the BaBar experiment at the

G. Bauer

A spate of remarkable new hadrons reported in 2003 may lead to unequivocal proof of states beyond conventional $q\bar{q}$ and $qqq$ structure. Claimed baryonic states Theta+, Phi, and Theta^0_c would consist of five quarks, and new D_{sJ}-states and/or X(3872) might contain four quarks. I review efforts to search for and study this ``new'' spectrosco

D0 Collaboration, V. Abazov

We present a measurement of the top quark pair (ttbar) production cross section in ppbar collisions at a center-of-mass energy of 1.96 TeV using 230 pb-1 of data collected by the DO detector at the Fermilab Tevatron Collider. We select events in the dilepton final states ee, emu and mumu based on kinematical properties consistent with ttbar events. For a top

Gonzalo J. Olmo

We compute the complete post-Newtonian limit of the Palatini form of f(R) gravities using a scalar-tensor representation. By comparing the predictions of these theories with laboratory and solar system experiments, we find a set of inequalities that any lagrangian f(R) must satisfy. The constraints imposed by those inequalities allow us to find explicit func

Gonzalo J. Olmo

We compute the complete post-Newtonian limit of the metric form of f(R) gravities using a scalar-tensor representation. By comparing the predictions of these theories with laboratory and solar system experiments, we find a set of inequalities that any lagrangian f(R) must satisfy. The constraints imposed by those inequalities allow us to find explicit bounds

Cedric Deffayet, Jan-Willem Rombouts

We show that the strong self-interaction of the scalar polarization of a massive graviton can be understood in terms of the propagation of an extra ghost-like degree of freedom, thus relating strong coupling to the sixth degree of freedom discussed by Boulware and Deser in their Hamiltonian analysis of massive gravity. This enables one to understand the Vain

Alan D. Rendall

This article is a guide to theorems on existence and global dynamics of solutions of the Einstein equations. It draws attention to open questions in the field. The local-in-time Cauchy problem, which is relatively well understood, is surveyed. Global results for solutions with various types of symmetry are discussed. A selection of results from Newtonian the

F. I. Mikhail, M. I. Wanas, A. B. Morcos

A direct and more general calculation of the limb effect connected with red-shift observations is obtained. Result agrees completely, in its general form, with that obtained from observations of the solar spectra but with different value for the maximum effect.

Stijn Dekeyser, Jan Hidders, Jan Paredaens, Roel Vercammen

Semistructured databases require tailor-made concurrency control mechanisms since traditional solutions for the relational model have been shown to be inadequate. Such mechanisms need to take full advantage of the hierarchical structure of semistructured data, for instance allowing concurrent updates of subtrees of, or even individual elements in, XML docume

Weiming Zhang, Shiqu Li

To study how to design steganographic algorithm more efficiently, a new coding problem -- steganographic codes (abbreviated stego-codes) -- is presented in this paper. The stego-codes are defined over the field with $q(q\ge2)$ elements. Firstly a method of constructing linear stego-codes is proposed by using the direct sum of vector subspaces. And then the p

Taneli Mielikäinen

Discovering patterns from data is an important task in data mining. There exist techniques to find large collections of many kinds of patterns from data very efficiently. A collection of patterns can be regarded as a summary of the data. A major difficulty with patterns is that pattern collections summarizing the data well are often very large. In this disse

A. Wiesmaier, M. Fischer, M. Lippert, J. Buchmann

The PIN/TAN-system is an authentication and authorization scheme used in e-business. Like other similar schemes it is successfully attacked by criminals. After shortly classifying the various kinds of attacks we accomplish malicious code attacks on real World Wide Web transaction systems. In doing so we find that it is really easy to outflank these systems.

Cary L. Pint, M. W. Roth, Carlos Wexler

We present the results of molecular dynamics (MD) studies of hexane physisorbed onto graphite for eight coverages in the range $0.875 \le ρ\le 1.05$ (in units of monolayers). At low temperatures the adsorbate molecules form a uniaxially incommensurate herringbone (UI-HB) solid. At high coverages the solid consists of adsorbate molecules that are primarily ro

Alain Delgado, Augusto Gonzalez, David J. Lockwood

We present theoretical results concerning inelastic light (Raman) scattering from semiconductor quantum dots. The characteristics of each dot state (whether it is a collective or single-particle excitation, its multipolarity, and its spin) are determined independently of the Raman spectrum, in such a way that common beliefs used for level assignments in expe

Pierfrancesco Buonsante, Vittorio Penna, Alessandro Vezzani

Ultracold bosons in optical superlattices are expected to exhibit fractional-filling insulating phases for sufficiently large repulsive interactions. On strictly 1D systems, the exact mapping between hard-core bosons and free spinless fermions shows that any periodic modulation in the lattice parameters causes the presence of fractional-filling insulator dom

A. Agliolo Gallitto, G. Bonsignore, M. Li Vigni

Nonlinear microwave response of different ceramic MgB2 samples has been investigated by the technique of second-harmonic emission. The second-harmonic signal has been investigated as a function of temperature, DC magnetic field and input microwave power. The attention has mainly been devoted to the response at low magnetic fields, where nonlinear processes a

Thorsten Krenke, Eyup Duman, Mehmet Acet, Eberhard F. Wassermann

The magnetocaloric effect (MCE) in paramagnetic materials has been widely used for attaining very low temperatures by applying a magnetic field isothermally and removing it adiabatically. The effect can be exploited also for room temperature refrigeration by using recently discovered giant MCE materials. In this letter, we report on an inverse situation in N

Christophe Poulard, Geoffroy Guéna, Anne-Marie Cazabat, A. Boudaoud

The dynamics of evaporation of wetting droplets has been investigated experimentally in an extended range of drop sizes, in order to provide trends relevant for a theoretical analysis. A model is proposed, which generalises Tanner's law, allowing us to smooth out the singularities both in dissipation and in evaporative flux at the moving contact line. A

I. A. Fomin

The arguments of Volovik are refuted.

Arsen V. Subashiev, Serge Luryi

Uniaxially patterned dielectric layers have an optical anisotropy that can be externally controlled. We study the effects of patterning the cladding or the core layer of a 3-layer optical waveguide on the polarization properties of propagating radiation. Particular attention is paid to the case when the core material is a semiconductor with optical gain. We

S. Bustingorry, E. A. Jagla

We study a model of interacting particles in two dimensions to address the relation between crystal-crystal transformations and pressure-induced amorphization. On increasing pressure at very low temperature, our model undergoes a martensitic crystal-crystal transformation. The characteristics of the resulting polycrystalline structure depend on defect densit

H. Wadati, M. Takizawa, T. T. Tran, K. Tanaka

Perovskite-type BiNiO$_3$ is an insulating antiferromagnet in which a charge disproportionation occurs at the Bi site. La substitution for Bi suppresses the charge disproportionation and makes the system metallic. We have measured the photoemission and x-ray absorption (XAS) spectra of Bi$_{1-x}$La$_{x}$NiO$_{3}$ to investigate how the electronic structure c

N. B. Kopnin, A. S. Mel'nikov, V. I. Pozdnyakova, D. A. Ryzhov

The interplay of geometrical and Andreev quantization in mesoscopic superconductors leads to giant mesoscopic oscillations of energy levels as functions of the Fermi momentum and/or sample size. Quantization rules are formulated for closed quasiparticle trajectories in the presence of normal scattering at the sample boundaries. Two generic examples of mesosc

A. Saichev, D. Sornette

Motivated by its potential application to earthquake statistics, we study the exactly self-similar branching process introduced recently by Vere-Jones, which extends the ETAS class of conditional branching point-processes of triggered seismicity. One of the main ingredient of Vere-Jones' model is that the power law distribution of magnitudes m' of da

Oleg Derzhko, Taras Krokhmalskii

We consider the ground-state properties of the s=1/2 Ising chain in a transverse field which varies regularly along the chain having a period of alternation 2. Such a model, similarly to its uniform counterpart, exhibits quantum phase transitions. However, the number and the position of the quantum phase transition points depend on the strength of transverse

Oleg Derzhko, Taras Krokhmalskii

We discuss the dynamic properties of the square-lattice spin-1/2 XY model obtained using the two-dimensional Jordan-Wigner fermionization approach. We argue the relevancy of the fermionic picture for interpreting the neutron scattering measurements in the two-dimensional frustrated quantum magnet Cs_2CuCl_4.

M. W. Zwierlein, J. R. Abo-Shaeer, A. Schirotzek, C. H. Schunck

Quantum-degenerate Fermi gases provide a remarkable opportunity to study strongly interacting fermions. In contrast to other Fermi systems, such as superconductors, neutron stars or the quark-gluon plasma, these gases have low densities and their interactions can be precisely controlled over an enormous range. Here we report observations of vortices in such

Robert K. Niven

The rate equation for an arbitrary mth order growth or decay reaction can be expressed in terms of the q-exponential function, with q equal to m. The analysis suggests that a wide variety of reaction rate (kinetic) processes and models, in chemistry, biology/ecology, unit operations and contaminant transport, are amenable to analysis by Tsallis' non-exte

A. Rodriguez-Prieto, A. Bergara

Recently reported structural complexity and superconducting transition in lithium under pressure has increased the interest in light alkalis, otherwise considered as simple metals and well known systems under normal conditions. In this work we present an analysis of the pressure induced Fermi surface deformation in lithium with increasing pressure. According

Joseph E. Davies, Olav Hellwig, Eric E. Fullerton, J. S. Jiang

Magnetization reversal in exchange-spring magnet films has been investigated by a First Order Reversal Curve (FORC) technique and vector magnetometry. In Fe/epitaxial-SmCo films, the reversal proceeds by a reversible rotation of the Fe soft layer, followed by an irreversible switching of the SmCo hard layer. The switching fields are clearly manifested by sep

C. Emary, B. Trauzettel, C. W. J. Beenakker

We describe a mechanism for the production of polarisation-entangled microwaves using intra-band transitions in a pair of quantum dots. This proposal relies neither on spin-orbit coupling nor on control over electron-electron interactions. The quantum correlation of microwave polarisations is obtained from orbital degrees of freedom in an external magnetic f

K. L. Adelberger, C. C. Steidel

We use the clustering of galaxies around distant active-galactic nuclei to derive an estimate of the relationship between galaxy and black hole mass that obtained during the ancient quasar epoch, at redshifts 2 <~ z <~ 3, when giant black holes accreted much of their mass. Neither the mean relationship nor its scatter differs significantly from what is obser

Naoki Seto

We discuss an astrometric timing effect on data analysis of continuous gravitational waves from rapidly rotating isolated neutron stars. Special attention is directed to the possibility of determining their distances by measuring the curvature of the wave fronts. We predict that if continuous gravitational waves from an unknown neutron star with a stable rot

P. Jakobsson, G. Bjornsson, J. P. U. Fynbo, G. Johannesson

We report the result of a search for Ly-alpha emission from the host galaxies of the gamma-ray bursts (GRBs) 030226 (z = 1.986), 021004 (z = 2.335) and 020124 (z = 3.198). We find that the host galaxy of GRB 021004 is an extended (around 8 kpc) strong Ly-alpha emitter with a restframe equivalent width (EW) of 68^{+12}_{-11} AA, and a star-formation rate of 1

B. Dirsch, T. Richtler, M. Gomez

We report on new observations obtained with the Magellan Clay-telescope of a tiny dust patch in the Sa-galaxy NGC 3269 in the Antlia galaxy cluster. It has already been suspected to be a projected Galactic foreground cloud. In this case a size of about 4 arcsec and a maximum absorption of ~1 mag in the B-band would make it unique so far. We present further e

Ben Hood, Andrew Collier Cameron, Stephen R. Kane, D. M. Bramich

We present results of our survey for planetary transits in the field of NGC 6940. We think nearly all of our observed stars are field stars. We have obtained high precision (3-10 millimags at the bright end) photometric observations of 50,000 stars spanning 18 nights in an attempt to identify low amplitude and short period transit events. We have used a matc

C. R. O&#39;Dell

The 3-D structure of the Helix Nebula has been addressed multiple times and is slowly yielding to application of monochromatic emission line imaging, high resolution spectroscopy, and photoionization theory. The inner structure of the nebula is a toroidal disk filled with doubly ionized helium and is ionization bounded, with an extended vertical component re

A. D. Schwope, V. Hambaryan, F. Haberl, C. Motch

We present a multi-epoch spectral and timing analysis of the isolated neutron star RBS1223. New XMM-Newton data obtained in January 2004 confirm the spin period to be twice as long as previously thought, P_spin = 10.31 s. The combined ROSAT, Chandra, XMM-Newton data (6 epochs) give, contrary to earlier findings, no clear indication of a spin evolution of the

A. Miglio, J. Montalban

We apply the Levenberg-Marquardt minimization algorithm to seismic and classical observables of the Alpha Cen binary system in order to derive the fundamental parameters of Alpha Cen A+B and to analyze the dependence of these parameters on the chosen observables, on their uncertainty and on the physics used in stellar modelling. The seismological data are th

V. G. Kurt, V. V. Sokolov, T. A. Fatkhullin, V. N. Komarova

The earliest BTA (SAO RAS 6-m telescope) spectroscopic observations of the GRB 030329 optical transient (OT) are presented, which almost coincide in time with the &#34;first break&#34; ($t\sim 0.5$ day after the GRB) of the OT light curve. The beginning of spectral changes are seen as early as $\sim 10-12$ hours after the GRB. So, the onset of the spectral c

Joanna Mikolajewska, Artur Rutkowski, Denise R. Goncalves, Anna Szostek

We report the first quiescent detection of KV UMa, the optical counterpart of XTE J1118+480 at near infrared. The observed magnitudes and colours are consistent with a K7-M0 V star, at the distance 1.4 +/- 0.2 kpc. The light curve shows strong orbital modulation with possible contamination from a superhump detected in the quiescent optical light curves.

Hylke B. J. Koers, Ralph A. M. J. Wijers

We investigate the fate of very compact, sudden energy depositions that may lie at the origin of gamma-ray bursts. Following on from the work of Cavallo and Rees (1978), we take account of the much higher energies now believed to be involved. The main effect of this is that thermal neutrinos are present and energetically important. We show that these may pro

L. Sidoli, S. Mereghetti, S. Larsson, M. Chernyakova

The High Mass X-ray Binary Pulsar SAXJ2103.5+4545 has been observed with INTEGRAL several times during the last outburst in 2002-2004. We report a comprehensive study of all INTEGRAL observations, allowing a study of the pulse period evolution during the recent outburst. We measured a very rapid spin-up episode, lasting 130days, which decreased the pulse per

I. Iwata, K. Ohta, K. Nakanishi, P. Chamaraux

The Local Void is the nearest void from us and is thought to be playing an important role in the kinematics of the local universe, especially as one of the suspected source of the motion of the Local Group. The imbalance between the mass in the Local Void region and that contained in the concentration at the opposite side might contribute to the velocity of

A. Mastrano, A. Melatos

A recent laboratory experiment (Blaauwgeers et al. 2003) suggests that a Kelvin-Helmholtz (KH) instability at the interface between two superfluids, one rotating and anisotropic, the other stationary and isotropic, may trigger sudden spin-up of the stationary superfluid. This result suggests that a KH instability at the crust-core ($^1S_0$-$^3P_2$-superfluid

I. Iwata, A. K. Inoue, D. Burgarella

We present results of VLT/FORS2 spectroscopy of galaxies at z~3 in the Hubble Deep Field-South (HDF-S). A sample of galaxies was drawn from the photo-z catalogue based on the HST/WFPC2 optical images and the deep near-infrared images obtained with VLT/ISAAC as a part of the FIRES project. We selected galaxies with photometric redshift between 2.5 and 4. Most

Fabrizio Brighenti, William G. Mathews

In explaining the relative metal abundances observed in galaxy groups and clusters, it is generally assumed that all metals created by supernovae are present either in visible stars or the hot gas. We discuss here the possibility that some of the iron expelled into the hot gas by Type Ia supernovae may have radiatively cooled, avoiding detection by X-ray and

S. Corbel, P. Kaaret, R. P. Fender, A. K. Tzioumis

We report on the formation and evolution of two large-scale, synchrotron-emitting jets from the black hole candidate H 1743-322 following its reactivation in 2003. In November 2003 after the end of its 2003 outburst, we noticed, in observations with the Australia Telescope Compact Array, the presence of a new and variable radio source about 4.6&#34; to the E

J. Farihi, P. R. Wood, B. Stalder

Spectroscopy and photometry demonstrate that SSSPM J1549$-$3544 is not a cool white dwarf but a high velocity metal-poor halo star.

Nobuyuki Iwamoto, Hideyuki Umeda, Nozomu Tominaga, Ken&#39;ichi Nomoto

The recent discovery of a hyper metal-poor (HMP) star, whose metallicity Fe/H is smaller than 1/100,000 of the solar ratio, together with one earlier HMP star, has raised a challenging question if these HMP stars are the actual first generation, low mass stars in the Universe. We argue that these HMP stars are the second generation stars being formed from ga

Jeremy Bailin, Daisuke Kawata, Brad K. Gibson, Matthias Steinmetz

Seven cosmological hydrodynamic simulations of disk galaxy formation are analyzed to determine the alignment of the disk within the dark matter halo and the internal structure of the halo. We find that the orientation of the outer halo, beyond ~0.1 r_vir, is unaffected by the presence of the disk. In contrast, the inner halo is aligned such that the halo min

Tomi Koivisto

An explicit proof of the vanishing of the covariant divergence of the energy-momentum tensor in modified theories of gravity is presented. The gravitational action is written in arbitrary dimensions and allowed to depend nonlinearly on the curvature scalar and its couplings with a scalar field. Also the case of a function of the curvature scalar multiplying

David Solano, Rodrigo Alvarado

We obtain a new kind of exact solution to vaccum Einstein field equations that contain both Minkowsian world and a special 5D curved spacetime with particularly free structure. This special world is defined by an arbitrary function and a space of three parameters. We suggest that this solution could correct (in principle) certain aspects of the physics in fl

S. V. Lototsky, B. L. Rozovskii

We study stochastic parabolic and elliptic PDEs driven by purely spatial white noise. Even the simplest equations driven by this noise often do not have a square-integrable solution and must be solved in special weighted spaces. We demonstrate that the Cameron-Martin version of the Wiener chaos decomposition is an effective tool to study both stationary and

Adilet Imambekov, Eugene Demler

We consider a one dimensional interacting bose-fermi mixture with equal masses of bosons and fermions, and with equal and repulsive interactions between bose-fermi and bose-bose particles. Such a system can be realized in experiments with ultracold boson and fermion isotopes in optical lattices. We use the Bethe-ansatz technique to find the ground state ener