November 2005 arXiv papers — page 23

Gerald V. Dunne, Hyunsoo Min

We present a general numerical method for computing precisely the false vacuum decay rate, including the prefactor due to quantum fluctuations about the classical bounce solution, in a self-interacting scalar field theory modeling the process of nucleation in four dimensional spacetime. This technique does not rely on the thin-wall approximation. The method

P. West

We extend the previously given non-linear realisation of E_{11} for the decomposition appropriate to IIB supergravity to include the ten forms that were known to be present in the adjoint representation. We find precise agreement with the results on ten forms found by closing the IIB supersymmetry algebra.

G. Bonelli, L. Bonora, A. Ricco

This paper is a continuation of hepth/0507224 where open topological B-models describing D-branes on 2-cycles of local Calabi--Yau geometries with conical singularities were studied. After a short review, the paper expands in particular on two aspects: the gauge fixing problem in the reduction to two dimensions and the quantum matrix model solutions.

G. Yu. Bogoslovsky

Within the framework of the Finslerian approach to the problem of violation of Lorentz symmetry, consideration is given to a flat axially symmetric Finslerian space of events, which is the generalization of Minkowski space. Such an event space arises from the spontaneous breaking of initial gauge symmetry and from the formation of anisotropic fermion-antifer

M. Yu. Kuchiev, V. V. Flambaum

The Coulomb problem for vector bosons W(+/-) propagating in an attractive Coulomb field incorporates a known difficulty, i.e. the total charge of the boson localized on the Coulomb center turns out infinite. This fact contradicts the renormalizability of the Standard model, which presumes that at small distances all physical quantities are well defined. The

L. Andrianopoli

Some recent results in the study of four dimensional supergravity flux compactifications are reviewed, discussing in particular the role of torsion on the compactification manifold in generating gauge charges for the effective four dimensional theories.

R. S. Raghavan

Resonant capture of antineutrinos can be accomplished by exploiting the monoenergetic antineutrinos emitted in bound state beta-decay. Extending this idea, I explore conditions for recoilless resonant capture in the system 3H - 3He. Observation of such transitions can set the stage for placing stringent limits on the neutrino parameter theta-13 on an ultra-s

G. G. Barnafoldi, P. Levai, G. Papp, G. Fai

RHIC data on high-$p_T$ hadron production display strong suppression in a wide rapidity region, indicating strong induced energy loss for both transversally and longitudinally traveling partons. We investigate the interplay of energy loss and rapidity dependence in a perturbative QCD improved parton model, and estimate the opacity of the produced hot matter

A. Daleo, R. Sassot

We analyze the order alpha_s^2 corrections to the single inclusive jet cross section in lepton-nucleon deep inelastic scattering. The full calculation is done analytically, in the small cone approximation, obtaining finite NLO partonic level cross sections for these processes. A detailed study of the different underlying partonic reactions is presented focus

Ana Alboteanu, Thorsten Ohl, Reinhold Rückl

We discuss the non-commutative extension of the standard model constructed with the Seiberg-Witten maps for SU(3)_C x SU(2)_L x U(1)_Y. Using the first-order approximation in the non-commutative parameters theta, we estimate the sensitivity of Z-gamma-production at the Tevatron and LHC from Monte Carlo simulation.

M. Czakon, J. Gluza, T. Riemann

We overview the general status of higher order corrections to Bhabha scattering and review recent progress in the determination of the two-loop virtual corrections. Quite recently, they were derived from combining a massless calculation and contributions with electron sub-loops. For a massive calculation, the self-energy and vertex master integrals are known

Gunnar Ingelman

The idea of diffractive processes with a hard scale involved, to resolve the underlying parton dynamics, was presented at the first Blois conference in 1985 and experimentally verified a few years later. Today hard diffraction is an active research field with high-quality data and new theoretical models. The trend from Regge-based pomeron models to QCD-based

Andreas Ringwald

The PVLAS collaboration has recently reported the observation of a rotation of the polarization plane of light propagating through a transverse static magnetic field. Such an effect can arise from the production of a light, m_A ~ meV, pseudoscalar coupled to two photons with coupling strength g_{Aγ} ~ 5x10^{-6} GeV^{-1}. Here, we review these experimental fi

Boris A. Arbuzov

In QCD with two light quarks with application of Bogolubov quasi-averages approach a possibility of spontaneous generation of an effective interaction, leading to the Nambu -- Jona-Lazinio model, is studied. Compensation equations for form-factor of the interaction is shown to have the non-trivial solution leading to theory with two parameters: average low-e

W. K. Sze

A modified Fritzsch ansatz for the quark mass matrices is proposed to account for the hierarchical structure of the CKM matrix. To allow for the observed CP asymmetry, restrictions have to be imposed on the relative phase degree of freedom among the weak eigenstates of the quark fields, as for example by certain additional symmetries. The ansatz can be accom

L. G. Moretto, K. A. Bugaev, J. B. Elliott, L. Phair

A system H with a Hagedorn-like mass spectrum imparts its unique temperature T_H to any other system coupled to it. An H system radiates particles in preexisting physical and chemical equilibrium. These particles form a saturated vapor at temperature T_H. This coexistence describes a first order phase transition. An H system is nearly indifferent to fragment

Stanley J. Brodsky, Michael Rijssenbeek

Summary of the XIth International Conference on Elastic and Diffractive Scattering in Chateau de Blois, France, May 15 - 20, 2005, summarizing both theoretical and experimental presentations and discussions.

Bohdan Grzadkowski, Zenro Hioki, Kazumasa Ohkuma, Jose Wudka

Search for new-physics through possible anomalous t tbar gamma, tbW and gamma gamma H couplings which are generated by SU(2) X U(1) gauge-invariant dimension-6 effective operators is discussed, using energy and angular distributions of final charged-lepton/ b-quark in gamma gamma -> t tbar -> l X / bX for various beam polarizations. Optimal beam polarization

Massimo D'Elia, Francesco Di Renzo, Maria Paola Lombardo

We summarize our results on the phase diagram of QCD with emphasis on the high temperature regime. For $T \ge 1.5 T_c$ the results are compatible with a free field behavior, while for $T \simeq 1.1 T_c$ this is not the case, clearly exposing the strongly interacting nature of QCD in this region

Gert Aarts, Chris Allton, Richie Morrin, Alan O Cais

We report first results for spectral functions of charmonium in 2-flavour QCD. The spectral functions are determined from vector and pseudoscalar correlators on a dynamical, anisotropic lattice. J/psi and eta_c are found to survive well into the deconfined phase before melting away at T<~2T_c. Current systematic uncertainties prevent us from drawing any defi

Toru Sekido, Katsuya Ishiguro, Yoshifumi Nakamura, Tsuneo Suzuki

The dual Meissner effect is described and numerically observed in a gauge-invariant way in lattice Monte-Carlo simulations in pure SU(2) QCD. The squeezing of the non-Abelian electric field between a pair of static quark and anti-quark occurs due to the solenoidal current coming from the gauge-invariant monopole-like quantity. Preliminary results are obtaine

Tsuneo Suzuki, Katsuya Ishiguro, Yoshifumi Nakamura, Toru Sekido

The dual Meissner effect is described and numerically observed in a gauge-invariant way in lattice Monte-Carlo simulations of pure SU(2) QCD. A gauge-invariant monopole-like quantity on the lattice is defined by a gauge-invariant Abelian-like field strength. The Abelian-like field strength is expressed in terms of a unit-vector in color space which is constr

Tsuneo Suzuki, Katsuya Ishiguro, Yoshifumi Nakamura, Toru Sekido

The dual Meissner effect is described and numerically observed in a gauge-invariant way in lattice Monte-Carlo simulations of pure SU(2) QCD. A gauge-invariant Abelian-like field strength is defined in terms of a unit-vector in color space which is constructed by a non-Abelian field strength itself. A gauge-invariant monopole-like quantity is defined by a vi

A. D. Krisch

There will be a review of the history of polarized proton beams, and a discussion of the unexpected and still unexplained large transverse spin effects found in several high energy proton-proton spin experiments at the ZGS, AGS and Fermilab. Next, there will be a discussion of present and possible future experiments on the violent elastic collisions of polar

Mark Lancaster

Precise measurements of the mass and width of the W boson are sensitive to radiative corrections and can be used to place limits on new physics beyond the Standard Model and validate the consistency of the model. In particular, the W boson mass constrains the mass of the, as yet unobserved, Higgs boson and the width can be used to place limits on the existen

Belle Collaboration

The mass of the $τ$-lepton has been measured in the decay modes $τ\to 3πν_τ$ and $τ\to 3ππ^0ν_τ$ using a pseudomass technique. The preliminary result is $1776.71\pm 0.25 {(stat)} \pm 0.62 {(syst)}$ MeV. The preliminary value of an upper limit on the relative mass difference between positive and negative $τ$ leptons is $|(M_{τ^+}-M_{τ^-})|/M_{\mathrm{average}

David Garfinkle

Cooperstock and Tieu have proposed a model to account for galactic rotation curves without invoking dark matter. I argue that no model of this type can work.

A. W. Beckwith

We review the results of a model of how nucleation of a new universe occurs, assuming a di quark identification for soliton-anti soliton constituent parts of a scalar field. Initially, we employ a false vacuum potential system; however ,when cosmological expansion is dominated by the Einstein cosmological constant at the end of chaotic inflation, the initial

A. Mikovic

We describe a class of spin foam models of four-dimensional quantum gravity which is based on the integration of the tetrad one-forms in the path integral for the Palatini action of General Relativity. In the Euclidian gravity case this class of models can be understood as a modification of the Barrett-Crane spin foam model. Fermionic matter can be coupled b

A. Kuiroukidis, D. B. Papadopoulos

We consider brane cosmologies within the context of five-dimensional actions with O(a&#39;) higher curvature corrections. The actions are compatible with bulk string amplitude calculations from heterotic string theory. We find wrapped solutions that satisfy the field equations in an approximate but acceptable manner given their complexity, where the internal

T. Papakostas

A generalization of the notion of surfaces of revolution in the spaces of General Relativity is presented. We apply this definition to the case of Carter&#39;s family [A] of solutions and we study the Kerr&#39;s metric with respect the above mentioned foliation.

Ratko V. Tomic

Quantized Indexing is a fast and space-efficient form of enumerative (combinatorial) coding, the strongest among asymptotically optimal universal entropy coding algorithms. The present advance in enumerative coding is similar to that made by arithmetic coding with respect to its unlimited precision predecessor, Elias coding. The arithmetic precision, executi

Junsheng Han, Paul H. Siegel

Let C be a linear code with length n and minimum distance d. The stopping redundancy of C is defined as the minimum number of rows in a parity-check matrix for C such that the smallest stopping sets in the corresponding Tanner graph have size d. We derive new upper bounds on the stopping redundancy of linear codes in general, and of maximum distance separabl

Grigoris Antoniou, David Billington, Guido Governatori, Michael J. Maher

Defeasible reasoning is a simple but efficient approach to nonmonotonic reasoning that has recently attracted considerable interest and that has found various applications. Defeasible logic and its variants are an important family of defeasible reasoning methods. So far no relationship has been established between defeasible logic and mainstream nonmonotonic

Matthew J. M. Peacock, Iain B. Collings, Michael L. Honig

This paper uses an incremental matrix expansion approach to derive asymptotic eigenvalue distributions (a.e.d.&#39;s) of sums and products of large random matrices. We show that the result can be derived directly as a consequence of two common assumptions, and matches the results obtained from using R- and S-transforms in free probability theory. We also giv

J. M. Carmona, S. Jimenez, J. Polonyi, A. Tarancon

We introduce an effective scalar field theory to describe the He-IV phase diagram, which can be considered as a generalization of the XY model which gives the usual lambda-transition. This theory results from a Ginzburg-Landau Hamiltonian with higher order derivatives, which allow to produce transitions between the superfluid, normal liquid and solid phases

M. Mueller

A simple explanation for the logarithmic aging of the photoconductivity in yttriumhydride is proposed. We show that the scaling (``simple&#39;&#39; aging) of the relaxation response with the illumination time t_w is consistent with the superposition of independently relaxing excitations with time offsets distributed over a window of width t_w.

G. Esen, M. S. Fuhrer

Controlled electromigration of gold nanowires of different cross-sectional areas to form nanogap junctions is studied using a feedback method. A linear correlation between the cross sectional area of the gold nanowires and the power dissipated in the junction during electromigration is observed, indicating that the feedback mechanism operates primarily by co

R. K. Bowles, I. Saika-Voivod

We present a simple off-lattice hard-disc model that exhibits glassy dynamics. The inherent structures are enumerated exactly, transitions between metabasins are well understood, and the particle configurations that act to facilitate dynamics are easily identified. The model readily maps to a coarse grained dynamic facilitation description.

Francesc Malet, Marti Pi, Manuel Barranco, Enrico Lipparini

We have studied the ground state structure of quantum strips within the local spin-density approximation, for a range of electronic densities between $\sim$ 5$\times10^4$ and 2$\times10^6$ cm$^{-1}$ and several strengths of the lateral confining potential. The results have been used to address the conductance $G$ of quantum strips. At low density, when only

Matthias Sperl

The fits of 0.4 Ca(NO_3)_2 0.6 K(NO_3) (CKN) by schematic mode-coupling models [V. Krakoviack and C. Alba-Simionesco, J. Chem. Phys. 117, 2161-2171 (2002)] are analyzed by asymptotic expansions. The validity of both the power-law and the Cole-Cole-peak solutions for the critical spectrum are investigated. It is found that the critical spectrum derived from t

G. Deville, R. Leturcq, D. L&#39;Hote, R. Tourbot

We have measured the resistance and the 1/f resistance noise of a two-dimensional low density hole system in a high mobility GaAs quantum well at low temperature. At densities lower than the metal-insulator transition one, the temperature dependence of the resistance is either power-like or simply activated. The noise decreases when the temperature or the de

H. W Eng, P. Limelette, W. Prellier, Ch. Simon

Transport properties of the good thermoelectric misfit oxide Ca$_3$Co$_4$O$_9$ are examined. In-plane resistivity and Hall resistance measurements were made on epitaxial thin films which were grown on {\it c}-cut sapphire substrates using the pulsed laser deposition technique. Interpretation of the in-plane transport experiments relates the substrate-induced

N. L. Bobrov, S. I. Beloborod&#39;ko, L. V. Tyutrina, V. N. Chernobay

It is shown that the two-gap approximation is applicable for describing the $dV/dI(V)$ spectra of LuNi$_{2}$B$_{2}$C-Ag point contacts in a wide interval of temperatures. The values and the temperature dependences of the large and the small gaps in the $ab$ plane and in the $c$ direction were estimated using the generalized BTK model and the equations of Bel

P. Lombardo, A. - M. Daré, R. Hayn

We present an approach based on the dynamical mean field theory which is able to give the excitation spectrum of a triply degenerate Hubbard model with a Hund&#39;s exchange invariant under spin rotation. The lattice problem can be mapped onto a local Anderson model containing 64 local eigenstates. This local problem is solved by a generalized non-crossing a

Mario De Menech

A phase--field method is applied to the modeling of flow and breakup of droplets in a T--shaped junction in the hydrodynamic regime where capillary and viscous stresses dominate over inertial forces, which is characteristic of microfluidic devices. The transport equations are solved numerically in the three--dimensional geometry, and the dependence of the dr

K. Kikoin, M. N. Kiselev, M. R. Wegewijs

We investigate transport through a mononuclear transition-metal complex with strong tunnel coupling to two electrodes. The ground state of this molecule is a singlet while the first excited state is a triplet. We show that a modulation of the tunnel-barrier due to a molecular distortion which couples to the tunneling induces a Kondo-effect, provided the disc

T. Vekua, D. C. Cabra, A. Dobry, C. Gazza

We investigate a simple model of a frustrated spin-1/2 Heisenberg chain coupled to adiabatic phonons under an external magnetic field. Using field theoretic methods complemented by extensive Density Matrix Renormalisation Group techniques generalized to include self-consistent lattice distortions, we show that magnetization plateaux at non-trivial rational v

H. Stark, T. C. Lubensky

Nematic liquid crystals are well modeled as a fluid of rigid rods. Starting from this model, we use a Poisson-bracket formalism to derive the equations governing the dynamics of nematic liquid crystals. We treat the spin angular momentum density arising from the rotation of constituent molecules about their centers of mass as an independent field and derive

V. Meerovich, V. Sokolovsky, L. Prigozhin, D. Rozman

Dynamic voltage-current characteristics of an HTS Ag/BiSCCO composite tape are studied both experimentally and theoretically. The tape is subjected by pulsed currents with different shapes and magnitude and voltage traces are measured using the four-point method with different location of potential taps on the sample surface. Clockwise and anticlockwise hyst

P. Lipavsky, K. Morawetz, J. Kolacek, T. J. Yang

A boundary condition for the Ginzburg-Landau wave function at surfaces biased by a strong electric field is derived within the de Gennes approach. This condition provides a simple theory of the field effect on the critical temperature of superconducting layers.

X. C. Zhang, D. R. Faulhaber, H. W. Jiang

In a GaAs/AlGaAs two-dimensional electron system with two occupied subbands, the experimentally determined phase diagram in the density-magnetic field plane exhibits rich topological features. Ring-like structures are observed at even integer filling factors, in the phase diagram. Even with the identical quantized Hall resistance values as those given rise b

Olivier Fruchart, André Thiaville

We propose a short overview of a few selected issues of magnetism in reduced dimensions, which are the most relevant to set the background for more specialized contributions to the present Special Issue. Magnetic anisotropy in reduced dimensions is discussed, on a theoretical basis, then with experimental reports and views from surface to single-atom anisotr

Satoshi Sugahara, Kok Leong Lee, Shinsuke Yada, Masaaki Tanaka

We investigated the origin of ferromagnetism in epitaxially grown Mn-doped Ge thin films. Using low-temperature molecular beam epitaxy, Mn-doped Ge films were successfully grown without precipitation of ferromagnetic Ge-Mn intermetallic compounds, such as Mn5Ge3. Magnetic circular dichroism measurements revealed that the epitaxially grown Mn-doped Ge films e

L. E. F. Foa Torres, H. M. Pastawski, E. Medina

We show that, in presence of a complex spectrum, antiresonances act as a precursor for dephasing enabling the crossover to a fully decoherent transport even within a unitary Hamiltonian description. This general scenario is illustrated here by focusing on a quantum dot coupled to a chaotic cavity containing a finite, but large, number of states using a Hamil

Sergei V. Kalinin, S. Jesse, A. Y. Borisevich, H. N. Lee

Strong coupling between electrical and mechanical phenomena and the presence of switchable polarization have enabled applications of ferroelectric materials for nonvolatile memories (FeRAM), data storage, and ferroelectric lithography. Understanding the local functionality of inorganic ferroelectrics including crystallographic orientation, piezoresponse, ela

E. Zaccarelli, C. Mayer, A. Asteriadi, C. N. Likos

We examine the vitrification and melting of asymmetric star polymers mixtures by combining rheological measurements with mode coupling theory. We identify two types of glassy states, a {\it single} glass, in which the small component is fluid in the glassy matrix of the big one and a {\it double} glass, in which both components are vitrified. Addition of sma

David P. DiVincenzo, Frederico Brito, Roger H. Koch

A complete analysis of the decoherence properties of a Josephson junction qubit is presented. The qubit is of the flux type and consists of two large loops forming a gradiometer and one small loop, and three Josephson junctions. The contributions to relaxation (T_1) and dephasing (T_ϕ) arising from two different control circuits, one coupled to the small loo

Masanobu Iwanaga, Teruya Ishihara

We reveal all the linear optical responses, reflection, transmission, and, diffraction, of typical one-dimensional metallic photonic crystal slabs (MPhCS) with the periodicity of a half micrometer. Maxwell equations for the structure of deep grooves are solved numerically with good precision by using the formalism of scattering matrix, without assuming perfe

A. V. Shytov, E. G. Mishchenko, H. -A. Engel, B. I. Halperin

An arbitrarily small concentration of impurities can affect the spin Hall conductivity in a two-dimensional semiconductor system. We develop a Boltzmann-like equation that can be used for impurity scattering with arbitrary angular dependence, and for arbitrary angular dependence of the spin-orbit field b(k) around the Fermi surface. For a model applicable to

M. Rigol, S. R. Manmana, A. Muramatsu, R. T. Scalettar

In a recent letter Machida et al. [Phys. Rev. Lett. 93, 200402 (2004)] concluded that in a trapped gas of fermions with repulsive interactions a superfluid phase appears around the Mott-insulator at the center of the trap. They base their conclusion on a negative binding energy, and a large weight for a singlet formed by particles located at opposite sides o

C. Knez, A. C. A. Boogert, K. M. Pontoppidan, J. E. Kessler-Silacci

A powerful way to observe directly the solid state inventory of dense molecular clouds is by infrared spectroscopy of background stars. We present Spitzer/IRS 5-20 micron spectra of ices toward stars behind the Serpens and Taurus molecular clouds, probing visual extinctions of 10-34 mag. These data provide the first complete inventory of solid-state material

B. J. Maughan, S. C. Ellis, L. R. Jones, K. O. Mason

We present an analysis of a 50ks XMM observation of the merging galaxy cluster ClJ0152.7-1357 at z=0.83. In addition to the two main subclusters and an infalling group detected in an earlier Chandra observation of the system, XMM detects another group of galaxies possibly associated with the cluster. This group may be connected to the northern subcluster by

A. Siemiginowska, C. C. Cheung, S. LaMassa, D. Burke

We report the first significant detection of an X-ray cluster associated with a powerful (L(bol) ~1e47 erg/sec) radio-loud quasar at high redshift (z=1.06). Diffuse X-ray emission is detected out to ~120 kpc from the CSS quasar 3C 186. A strong Fe-line emission at the z(rest)=1.06 confirms its thermal nature. We find that the CSS radio source is highly overp

Krzysztof Gozdziewski, Maciej Konacki, Andrzej J. maciejewski

We perform a dynamical analysis of the recently published radial velocity (RV) measurements of a few solar type stars which host multiple Jupiter-like planets. In particular, we re-analyze the data for HD 202206, 14 Her, HD 37124 and HD 108874. We derive dynamically stable configurations which reproduce the observed RV signals using our method called GAMP (a

J. Davy Kirkpatrick, Travis S. Barman, Adam J. Burgasser, Mark R. McGovern

While following up L dwarf candidates selected photometrically from the Two Micron All Sky Survey, we uncovered an unusual object designated 2MASS J01415823-4633574. Its optical spectrum exhibits very strong bands of vanadium oxide but abnormally weak absorptions by titanium oxide, potassium, and sodium. Morphologically such spectroscopic characteristics fal

Christopher S. Peters, John R. Thorstensen

We present spectroscopy of four cataclysmic variables. Using radial velocity measurements, we find orbital periods for the first time. The stars and their periods are GY Hya, 0.347230(9) d; SDSS J204448-045929, 1.68(1) d; V392 Hya, 0.324952(5) d; and RX J1951.7+3716, 0.492(1) d. We also detect the spectra of the secondary stars, estimate their spectral types

Laurent Eyer

Gaia is a cornerstone mission of the European Space Agency (ESA) selected in 2000, with a target launch date of 2011. The Gaia mission will perform a survey of about 1 billion sources brighter than V=20. Its goal is to provide astrometry leading to parallaxes, proper-motions and positions. Astrometric data are complemented by multicolour photometry and a spe

R. Sambruna, M. Gliozzi, D. Donato, L. Maraschi

We present deep (70-80 ks) Chandra and multicolor HST ACS images of two jets hosted by the powerful quasars 1136-135 and 1150+497, together with new radio observations. The sources have an FRII morphology and were selected from our previous X-ray and optical jet survey for detailed follow up aimed at obtaining better constraints on the jet multiwavelength mo

Laurent Eyer

How to analyse Terabytes of photometric data, and extract knowledge on variable stars? How to detect variable phenomena? How to combine different photometric bands? Which algorithm to search for periods? How to characterize and classify the detected variable objects? Many questions, but certainly no definitive answers yet. We present several aspects which ar

J Crummy, AC Fabian, L Gallo, RR Ross

We present a large sample of type 1 active galactic nuclei (AGN) spectra taken with XMM-Newton, and fit them with both the conventional model (a power law and black body) and the relativistically-blurred photoionized disc reflection model of Ross and Fabian (2005). We find the disc reflection model is a better fit. The disc reflection model successfully repr

Rich Townsend

I review the basic concepts of the Rigidly Rotating Magnetosphere model for the circumstellar plasma distribution around the helium-strong star sigma Ori E. I demonstrate that the model can furnish a good fit to the photometric, spectroscopic and magneticv ariability exhibited by this star, and argue that the variability of other helium-strong stars may be a

Rich Townsend

The stability of retrograde mixed modes in rotating B-type stars is investigated. It is found that these modes are susceptible to kappa-mechanism excitation, due to the iron opacity bump at log T ~ 5.3. The findings are discussed in the context of the pulsation of SPB and Be stars.

Mary Oksala, Rich Townsend

We present new UBVRI observations of the magnetic Bp star sigma Ori E. The basic features of the star&#39;s lightcurve have not changed since the previous monitoring by Hesser et al. (1977), indicating that the star&#39;s magnetosphere has remained stable over the past three decades. Interestingly, we find a rotation period that is slightly longer than in th

F. D. A. Hartwick

Nucleosynthetic signatures in common between the gas responsible for the high redshift Lyman alpha forest and a subsample of extremely metal poor stars are found. A simple mass loss model of chemical evolution with physically motivated parameters provides a consistent picture in which the gas is identified with that lost by supernova-driven winds during the

Manolis K. Georgoulis

Intermittent magnetohydrodynamical turbulence is most likely at work in the magnetized solar atmosphere. As a result, an array of scaling and multi-scaling image-processing techniques can be used to measure the expected self-organization of solar magnetic fields. While these techniques advance our understanding of the physical system at work, it is unclear w

Manolis K. Georgoulis, Barry J. LaBonte

We outline a general methodology to infer the inductive velocity field vector in solar active regions. For the first time, both the field-aligned and the cross-field velocity components are reconstructed. The cross-field velocity solution accounts for the changes of the vertical magnetic field seen between a pair of successive active-region vector magnetogra

Georges Meynet, Raphael Hirschi, Sylvia Ekstrom, Andre Maeder

At very low metallicity, the effects of differential rotation have a more important impact on the evolution of stars than at high metallicity. Rotational mixing leads to the production of great quantities of helium and of primary $^{14}$N by massive stars. Rotation induces important mass loss and allows stars to locally strongly enrich the interstellar mediu

S. Ghizzardi, S. Molendi, A. Leccardi, M. Rossetti

We perform a systematic search of cold fronts in a sample of 62 clusters observed with XMM-Newton with redshift ranging from 0.01 to 0.3. We detect one or more cold fronts in 21 (34%) of our objects. A large fraction (87.5%) of nearby clusters 0.01 < z < 0.04 host a cold front while only 20% of the distant clusters, mostly merging clusters, do so. The absenc

Jiri Krticka, Jiri Kubat

We review basic physics of line-driven stellar winds of OB stars. We discuss elementary processes due to which stellar winds are accelerated on a microscopic level. We show how these microscopic processes may enable the outflow and how they determine wind properties on a macroscopic level. We discuss shortcomings of present wind theories and future wind mode

S. P. Bamford, A. Aragon-Salamanca, B. Milvang-Jensen

We examine the evolution of the Tully-Fisher relation (TFR) using a sample of 89 field spirals, with 0.1 < z < 1, for which we have measured confident rotation velocities (Vrot). By plotting the residuals from the local TFR versus redshift, or alternatively fitting the TFR to our data in several redshift bins, we find evidence that luminous spiral galaxies a

John D. Barrow

We review properties of theories for the variation of the gravitation and fine structure &#39;constants&#39;. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that are consistent with time-variation in the fine structure &#39;constant&#39; since a redshift of 3.5. The behaviour of

Frederic Meynadier, Mohammad Heydari-Malayeri, Nolan Walborn

We study the Large Magellanic Cloud HII region N 214C using imaging and spectroscopy obtained at the ESO New Technology Telescope. On the basis of the highest resolution images so far obtained of the OB association LH 110, we show that the main exciting source of the HII region, Sk -71 51, is in fact a tight cluster of massive stars consisting of at least 6

A. L. Longinotti, S. Sim, K. Nandra, P. O&#39;Neill

In the recent literature on AGNs it has been often reported that spectra of Seyfert 1 Galaxies show resonant absorption lines of Fe K which are redshifted from the rest frame position. Such lines are often found with marginal significance but, if real, could potentially open up new avenues to study the circumnuclear gas in the black hole environment. It is a

Robert C Nichol, Garry Smith, Christopher J Miller, Chris Genovese

We outline our first steps towards marrying two new and emerging technologies; the Virtual Observatory (e.g, AstroGrid) and the computational grid. We discuss the construction of VOTechBroker, which is a modular software tool designed to abstract the tasks of submission and management of a large number of computational jobs to a distributed computer system.

Tom Dwelly, Mathew J. Page

We use the very deep XMM-Newton observations in the CDF-S to measure the distribution of absorption in the AGN population. We describe the Monte Carlo method used to unveil the intrinsic properties of the AGN using their multi-band X-ray colours. The measured distribution of AGN in z, L_X and N_H space is compared with the distributions predicted by a number

M. P. Esquej, B. Altieri, D. Bermejo, M. J. Freyberg

The XMM-Newton satellite is the most sensitive X-ray observatory flown to date due to the great collecting area of its mirrors coupled with the high quantum efficiency of the EPIC detectors. It performs slewing manoeuvers between observation targets tracking almost circular orbits through the ecliptic poles due to the Sun constraint. Slews are made with the

T. Bertram, A. Eckart, M. Krips, C. Straubmeier

We present the results of a survey for CO line emission from a sample of nearby QSO hosts taken from the Hamburg/ESO survey (HES) and the Veron-Cetty and Veron quasar catalogue. From a total of 39 observed sources we clearly detected 5 objects with >10sigma signals (HE 0108-4743, HE 0224-2834, J035818.7-612407, HE 1029-1831, HE 2211-3903). Further 6 sources

Ignasi Ribas

Binary systems have long been recognized as the source of powerful astrophysical diagnostics. Among the many applications of binary stars, they have been used as probes of stellar structure and evolution (both of single and binary stars) in a broad range of masses, evolutionary stages, and chemical compositions, and as indicators of distance and time. With t

Deng Xinfa, Ma Xinsheng, Luo Chenghong, Zhang Qun

We have constructed a Main galaxy subsample with redshifts in the range 0.08<=z<=0.12 from SDSS Data Release 3 (SDSS DR3), and refer to this subsample as &#34;MGSU&#34;(It contains 67777 galaxies). By cluster analysis, two isolated Main galaxy samples are extracted from this subsample. It turns out that two isolated Main galaxy samples identified at differen

Ignasi Ribas

Eclipsing binaries with M-type components are still rare objects. Strong observational biases have made that today only a few eclipsing binaries with component masses below 0.6 Msun and well-determined fundamental properties are known. However, even in these small numbers the detailed comparison of the observed masses and radii with theoretical predictions h

Marcello Lissia, Piero Quarati

This article illustrates how very small deviations from the Maxwellian exponential tail, while leaving unchanged bulk quantities, can yield dramatic effects on fusion reaction rates and discuss several mechanisms that can cause such deviations.

J. Rodriguez, A. Bodaghee, P. Kaaret, J. A. Tomsick

We report on observations of the X-ray pulsar IGR J16320-4751 (a.k.a. AX J1631.9-4752) performed simultaneously with INTEGRAL and XMM-Newton. We refine the source position and identify the most likely infrared counterpart. Our simultaneous coverage allows us to confirm the presence of X-ray pulsations at ~1300 s, that we detect above 20 keV with INTEGRAL for

J. Fritz, A. Franceschini, E. Hatziminaoglou

We describe improved modelling of the emission by dust in a toroidal--like structure heated by a central illuminating source within Active Galactic Nuclei (AGN). We chose a simple but realistic torus geometry, a flared disc, and a dust grain distribution function including a full range of grain sizes. The optical depth within the torus is computed in detail

C. J. Davis, B. Nisini, M. Takami, T. -S. Pyo

We present long-slit H- and K-band spectroscopy of the low-mass outflow source SVS 13, obtained with the adaptive-optics assisted imager-spectrometer NACO on the VLT. With a spatial resolution of < 0.25 arcsec and a pixel scale of 0.027 arcsec we precisely establish the relative offsets of H2, [FeII], CO, HI and NaI components from the source continuum. The

Celeste M. Yeates, J. Christopher Clemens, S. E. Thompson, F. Mullally

The lightcurves of variable DA stars are usually multi-periodic and non-sinusoidal, so that their Fourier transforms show peaks at eigenfrequencies of the pulsation modes and at sums and differences of these frequencies. These combination frequencies provide extra information about the pulsations, both physical and geometrical, that is lost unless they are a

B. Mennesson, C. Koresko, M. J. Creech-Eakman, E. Serabyn

We report interferometric observations of the semi-regular variable star RS CrB, a red giant with strong silicate emission features. The data were among the first long baseline mid-infrared stellar fringes obtained between the Keck telescopes, using parts of the new nulling beam combiner. The light was dispersed by a low-resolution spectrometer, allowing sim

R. M. Quimby, E. S. Rykoff, S. A. Yost, F. Aharonian

We present the unfiltered ROTSE-III light curve of the optical transient associated with GRB 050319 beginning 4 s after the cessation of gamma-ray activity. We fit a power-law function to the data using the revised trigger time given by Chincarini et al. (2005), and a smoothly broken power-law to the data using the original trigger disseminated through the G

L. Chemin, C. Balkowski, V. Cayatte, C. Carignan

A catalog of ionized gas velocity fields for a sample of 30 spiral and irregular galaxies of the Virgo cluster has been obtained by using three-dimensional optical data. The aim of this survey is to study the influence of high density environments on the gaseous kinematics of local cluster galaxies. Observations of the Halpha line by means of Fabry-Perot int

Eric V. Linder

Distance-redshift data can impose strong constraints on dark energy models even when the equation of state is oscillatory. Despite the double integral dependence of the distance on the equation of state, precision measurement of the distance-redshift relation for z=0-2 is more incisive than the linear growth factor, CMB last scattering surface distance, and