June 2006 arXiv papers — page 15

L. Thomas Ramsey, Colin C. Graham

Let $e^{2πi\Q}$ denote the set of roots of unity. We consider subsets $E\subset e^{2πi\Q}$ that are quasi-independent or algebraically independent (as subsets of the discrete plane). A bijective map on $e^{2πi\Q}$ preserves the algebraically independent sets iff it preserves the quasi-independent sets, and those maps are characterized. The effect on the size

J. Martin Lindsay, Stephen J. Wills

A new method for the construction of Fock-adapted operator Markovian cocycles is outlined, and its use is illustrated by application to a number of examples arising in physics and probability. The construction uses the Trotter-Kato Theorem and a recent characterisation of such cocycles in terms of an associated family of contraction semigroups.

Ricardo Bianconi

We prove that if A is an infinite von Neumann algebra (i. e., the identity can be decomposed as a sum of a sequence of pairwise disjoint projections, all equivalent to the identity) then the cyclic cohomology of A vanishes. We show that the method of the proof applies to certain algebras of infinite matrices.

Angela Ortega

Our main theorem is an improvement of the Criterion of Kanev about Prym-Tyurin varieties induced by correspondences, which includes correspondences with fixed points. We give some examples of Prym--Tyurin varieties using this criterion.

Erik Talvila

If $f$ is a Henstock--Kurzweil integrable function on the real line, the Alexiewicz norm of $f$ is $\|f\|=\sup_I|\int_I f|$ where the supremum is taken over all intervals $I\subset\R$. Define the translation $τ_x$ by $τ_xf(y)=f(y-x)$. Then $\|τ_xf-f\|$ tends to 0 as $x$ tends to 0, i.e., $f$ is continuous in the Alexiewicz norm. For particular functions, $\|

Ian Melbourne, Matthew Nicol

We prove an almost sure invariance principle (approximation by d-dimensional Brownian motion) for vector-valued Holder observables of large classes of nonuniformly hyperbolic dynamical systems. These systems include Axiom~A diffeomorphisms and flows as well as systems modelled by Young towers with moderate tail decay rates. In particular, the position variab

John Cantwell, Lawrence Conlon

For sutured 3-manifolds M, there is a sutured Thurston norm due to Scharlemann. We show how depth one foliations of M and corresponding fibrations and the usual Thurston norm on the double of M are useful tools for computing this norm. In many examples, the faces of the unit ball of the sutured norm are related to cones of depth one foliations of M but examp

Glenn Shafer, Vladimir Vovk

Andrei Kolmogorov's Grundbegriffe der Wahrscheinlichkeits-rechnung put probability's modern mathematical formalism in place. It also provided a philosophy of probability--an explanation of how the formalism can be connected to the world of experience. In this article, we examine the sources of these two aspects of the Grundbegriffe--the work of the e

Sebastiaan A. Terwijn

We investigate the structure of the Medvedev lattice as a partial order. We prove that every interval in the lattice is either finite, in which case it is isomorphic to a finite Boolean algebra, or contains an antichain of size 2^2^\aleph_0, the size of the lattice itself. We also prove that it is consistent that the lattice has chains of this size, and in f

S. S. Podkorytov

Let $X$ be a simply connected pointed space with finitely generated homotopy groups. Let $Π_n(X)$ denote the set of all continuous maps $a:I^n\to X$ taking $\partial I^n$ to the basepoint. For $a\inΠ_n(X)$, let $[a]\inπ_n(X)$ be its homotopy class. For an open set $E\subset I^n$, let $Π(E,X)$ be the set of all continuous maps $a:E\to X$ taking $E\cap\partial

Abdelkader Mokkadem, Mariane Pelletier

Let $f$ be a probability density and $C$ be an interval on which $f$ is bounded away from zero. By establishing the limiting distribution of the uniform error of the kernel estimates $f_n$ of $f$, Bickel and Rosenblatt (1973) provide confidence bands $B_n$ for $f$ on $C$ with asymptotic level $1-α\in]0,1[$. Each of the confidence intervals whose union gives

David Gerard-Varet, Thierry Paul

A systematic mathematical methodology for derivation of boundary layer expansions is presented. An explicit calculation of boundary layer sizes is given and proved to be coordinates system independent. It relies on asymptotic properties of symbols of operators. Several examples, including the quasigeostrophic model, are discussed.

Thomas Branson, Doojin Hong

We give explicit formulas for the intertwinors of all orders on the twistor bundle over $S^1\times S^{n-1}$ using spectrum generating technique introduced in \cite{BOO:96}.

F. Radoux

In [8], P. Lecomte conjectured the existence of a natural and projectively equivariant quantization. In [1], M. Bordemann proved this existence using the framework of Thomas-Whitehead connections. In [9], we gave a new proof of the same theorem thanks to the Cartan connections. After these works there was no explicit formula for the quantization. In this pap

A. A. Lopatin

A base of a relatively free associative algebra with the identity x^3=0 over a field of arbitrary characteristic is found. As an application a minimal generating system of the 3x3 matrix invariant algebra is determined.

Vesselin Drensky, Jie-Tai Yu

We develop a new method to deal with the Cancellation Conjecture of Zariski in different environments. We prove the conjecture for free associative algebras of rank two. We also produce a new proof of the conjecture for polynomial algebras of rank two over fields of zero characteristic.

Roman Drnovšek, Vladimir Müller, Nika Novak

We prove that a (bounded linear) operator acting on an infinite-dimensional, separable, complex Hilbert space can be written as a product of two quasi-nilpotent operators if and only if it is not a semi-Fredholm operator. This solves the problem posed by Fong and Sourour in 1984. We also consider some closely related questions. In particular, we show that an

M. Draief, A. Ganesh, L. Massoulie

We study how the spread of computer viruses, worms, and other self-replicating malware is affected by the logical topology of the network over which they propagate. We consider a model in which each host can be in one of 3 possible states - susceptible, infected or removed (cured, and no longer susceptible to infection). We characterise how the size of the p

Philippe Carmona, Yueyun Hu

In this note we show that in any dimension $d$, the strong disorder property implies the strong localization property. This is established for a continuous time model of directed polymers in a random environment : the parabolic Anderson Model.

Greg W. Anderson

Let $k$ be a local field of positive characteristic. Let $L$ be a cocompact discrete subgroup of $k$. Let $U$ be an open compact subgroup of $k$. Let $\ell$, $u$ and $a$ be elements of $k$, with $a$ nonzero. We study the behavior of the product $\prod_{0\neq x\in (\ell+L)\cap a(u+U)}x$ as $a$ varies. Our main result, which blends harmonic analysis and local

David Avis, Hiroshi Imai, Tsuyoshi Ito

The cut polytope of a graph arises in many fields. Although much is known about facets of the cut polytope of the complete graph, very little is known for general graphs. The study of Bell inequalities in quantum information science requires knowledge of the facets of the cut polytope of the complete bipartite graph or, more generally, the complete k-partite

Allan Rosencwaig

We apply a Casimir energy approach to evaluate the self-energy or one-photon radiative correction for an electron in a hydrogen orbital. This linking of the Lamb shift to the Casimir effect is obtained by treating the hydrogen orbital as a one-electron shell and including the probability of the electron being at a particular radius in that orbital and the pr

Bobby S Acharya, Michael R Douglas

We present evidence that the number of string/$M$ theory vacua consistent with experiments is a finite number. We do this both by explicit analysis of infinite sequences of vacua and by applying various mathematical finiteness theorems.

S. K. Singh, M. J. Vicente Vacas

The quasielastic weak production of $Λ$ and $Σ$ hyperons from nucleons and nuclei induced by antineutrinos is studied in the energy region of some ongoing neutrino oscillation experiments in the intermediate energy region. The hyperon nucleon transition form factors determined from neutrino nucleon scattering and an analysis of high precision data on semilep

David E. Morrissey, James D. Wells

When an abelian gauge theory with integer charges is spontaneously broken by the expectation value of a charge Q field, there remains a Z_Q discrete symmetry. In a supersymmetric theory, holomorphy adds additional constraints on the operators that can appear in the effective superpotential. As a result, operators with the same mass dimension but opposite sig

Alain Le Yaouanc, Dimitri Melikhov, Vincent Morenas, Lluis Oliver

A detailed discussion based on exact calculations, possible in the non relativistic quark model, is given to show that there is no 1/m_Q term in the heavy quark expansion of totally integrated semileptonic decay rates. More generally, it is shown that OPE holds with very few terms in the expansion, at least in the harmonic oscillator model.

A. D. Dolgov

A comparison of the standard models in particle physics and in cosmology demonstrates that they are not compatible, though both are well established. Basics of modern cosmology are briefly reviewed. It is argued that the measurements of the main cosmological parameters are achieved through many independent physical phenomena and this minimizes possible inter

G. Soyez

In these proceedings, we shall first recall the evolution equations arising when increasing the rapidity $Y=\log(s)$ within the perturbative QCD regime. We shall then summarise the main properties on their asymptotic solutions and discuss the physical picture emerging from our analysis.

Henryk Czyz

A short review of the status of the theoretical developments concerning the radiative return method is presented. The emphasis is on the construction of the PHOKHARA Monte Carlo event generator and its tests. It is advocated that the radiative return method provides not only with the hadronic cross section extraction competitive with and complementary to the

S. Albino, F. Deppisch, R. Rückl

We present and discuss constraints on supersymmetric type I seesaw models imposed by neutrino data, charged lepton flavor violation and thermal leptogenesis.

T. M. Aliev, M. Savci

We study the exclusive (Lambda_b -> Λl^+ l^-) decay in the Appelquist, Chang, Dobrescu model within one universal extra dimension. We investigate the sensitivity of the branching ratio, lepton polarization and forward-backward asymmetry A_{FB} to the compactification parameter (1/R) We obtain that the branching ratio changed about 50% compared to the SM valu

A. Borstnik Bracic, M. Breskvar, D. Lukman, N. S. Mankoc Borstnik

In this letter we try to answer those of the open questions of the Standard model which concern the appearance of families, mass protection mechanism and the Yukawa couplings - by using the approach (proposed by one of us), which suggests a new way beyond the Standard model. The approach has in the starting action for fermions, which carry in d(=1 +13)-dimen

Wojciech Krolikowski

The off-diagonal part of the active-neutrino mass matrix is constructed from two $3\times 3$ matrices playing the role of annihilation and creation matrices acting in the neutrino-generation space of $ν_e, ν_μ, ν_τ$. The construction leads to a new relation, $M_{μτ} = 4\sqrt{3} M_{e μ} $, which predicts in the case of tribimaximal neutrino mixing that $m_3 -

Koushik Ghosh, Probhas Raychaudhuri

We have used both the Date-Compensated Discrete Fourier Transform and Periodogram analysis of the monthly solar neutrino flux data from (1) SAGE detector during the period from 1st January 1990 to 31st December 2000; (2) SAGE detector during the period from April 1998 to December 2001; (3) GALLEX detector during the period from May 1991 to January 1997; (4)

Koushik Ghosh, Probhas Raychaudhuri

The scaling behaviours of the monthly solar neutrino flux data from (1) SAGE detector during the period from 1st January 1990 to 31st December 2000; (2) SAGE detector during the period from April 1998 to December 2001; (3) GALLEX detector during the period from May 1991 to January 1997; (4) GNO detector during the period from May 1998 to December 2001; (5) G

B. R. Heckel, C. E. Cramer, T. S. Cook, E. G. Adelberger

We used a torsion pendulum containing $\sim 9 \times 10^{22}$ polarized electrons to search for CP-violating interactions between the pendulum's electrons and unpolarized matter in the laboratory's surroundings or the sun, and to test for preferred-frame effects that would precess the electrons about a direction fixed in inertial space. We find $|g_{

The BABAR Collaboration, B. Aubert

We present a search for the decay of a B0 or B0bar meson to a K*0bar K0 or K*0 K0bar final state, using a sample of approximately 232 million BBbar events collected with the BABAR detector at the PEP-II asymmetric energy e+e- collider at SLAC. The measured branching fraction is B(B0 --> K*0bar K0) + B(B0 --> K*0 K0bar) = (0.2+0.9-0.8+0.1-0.3)x 10-6. We obtai

Brent Preston, Eric Poisson

The geometrical meaning of the Eddington-Finkelstein coordinates of Schwarzschild spacetime is well understood: (i) the advanced-time coordinate v is constant on incoming light cones that converge toward r=0, (ii) the angles theta and phi are constant on the null generators of each light cone, (iii) the radial coordinate r is an affine-parameter distance alo

Brent Preston, Eric Poisson

Continuing work initiated in an earlier publication [Phys. Rev. D 69, 084007 (2004)], we construct a system of light-cone coordinates based at a geodesic world line of an arbitrary curved spacetime. The construction involves (i) an advanced-time or a retarded-time coordinate that labels past or future light cones centered on the world line, (ii) a radial coo

Lorenzo Iorio

According to general relativity, the gravitomagnetic Lense-Thirring force of Mars would secularly shift the orbital plane of the Mars Global Surveyor (MGS) spacecraft by an amount of 1.5 m, on average, in the cross-track direction over 5 years. The determined cross-track post-fit residuals of MGS, built up by neglecting just the gravitomagnetic force in the

Matthew J. Benacquista, Lee Samuel Finn, Shane L. Larson, Louis J. Rubbo

The principal goal of the \emph{LISA Science Analysis Workshop} is to encourage the development and maturation of science analysis technology in preparation for LISA science operations. Exactly because LISA is a pathfinder for a new scientific discipline -- gravitational wave astronomy -- LISA data processing and science analysis methodologies are in their i

Frances White

Explicit expressions for the quasi-Kinnersley tetrad for the quasi-Kerr metric are given. These provide a very clear and simple example of the quasi-Kinnersley tetrad, and may be useful in the future development of a `quasi-Teukolsky' scheme for the analysis of perturbation equations in spacetimes which are Petrov type I but in some sense close to type D

Maciej Dunajski, Maciej Przanowski

We review the integrable systems which arise as symmetry reductions of Plebanski's heavenly equations, and their generalisations. We also show that all four-dimensional null Kahler-Einstein (or type N hyper-heavenly) metrics with symmetry can be found from solutions to a variable coefficient generalisation of the dispersionless Kadomtsev-Petviashvili equ

C. Baier, N. Bertrand, Ph. Schnoebelen

We prove a general finite convergence theorem for "upward-guarded" fixpoint expressions over a well-quasi-ordered set. This has immediate applications in regular model checking of well-structured systems, where a main issue is the eventual convergence of fixpoint computations. In particular, we are able to directly obtain several new decidability res

F. J. Manjon, D. Errandonea, N. Garro, J. Pellicer-Porres

Room-temperature Raman scattering has been measured in lead tungstate up to 17 GPa. We report the pressure dependence of all the Raman modes of the tetragonal scheelite phase (PbWO4-I, space group I41/a), which is stable at ambient conditions. Upon compression the Raman spectrum undergoes significant changes around 6.2 GPa due to the onset of a partial struc

V. G. Kogan, R. Prozorov, S. L. Bud'ko, P. C. Canfield

The field dependence of the vortex core size $ξ(B)$ is incorporated in the London model, in order to describe reversible magnetization $M(B,T)$ for a number of materials with large Ginzburg-Landau parameter $κ$. The dependence $ξ(B)$ is directly related to deviations in $M(\ln B)$ from linear behavior prescribed by the standard London model. A simple method

David Pekker, Roman Barankov, Paul M. Goldbart

Recent experiments by Sato et al. [1] have explored the dynamics of $^4$He superflow through an array of nanopores. These experiments have found that, as the temperature is lowered, phase-slippage in the pores changes its character, from synchronous to asynchronous. Inspired by these experiments, we construct a model to address the characteristics of phase-s

Vladimir Privman, Alexander Dementsov, Igor Sokolov

We report on our progress towards continuum rate equation modeling, as well as numerical simulations, of self-healing of fatigue in composites reinforced with glue carrying nanoporous fibers. We conclude that with the proper choice of the material parameters, effects of fatigue can be partially overcome and degradation of mechanical properties can be delayed

J. Milton Pereira, V. Mlinar, F. M. Peeters, P. Vasilopoulos

We report the existence of confined massless fermion states in a graphene quantum well (QW) by means of analytical and numerical calculations. These states show an unusual quasi-linear dependence on the momentum parallel to the QW: their number depends on the wavevector and is constrained by electron-hole conversion in the barrier regions. An essential diffe

N. Plakida, V. Oudovenko

A microscopic theory for electronic spectrum of the CuO2 plane within an effective p-d Hubbard model is proposed. Dyson equation for the one-electron Green function in terms of the Hubbard operators is derived which is solved self-consistently for the self-energy evaluated in the noncrossing approximation. Electron scattering on spin fluctuations induced by

I. M. Sokolov, J. Klafter

We discuss the response of continuous time random walks to an oscillating external field within the generalized master equation approach. We concentrate on the time dependence of the two first moments of the walker&#39;s displacements. We show that for power law waiting time distributions with 0 < alpha < 1 corresponding to a semi-Markovian situation showing

Baleegh Abdo, Eran Arbel-Segev, Oleg Shtempluck, Eyal Buks

We exploit nonlinearity in NbN superconducting stripline resonators, which is originated by local thermal instability, for studying stochastic resonance. As the resonators are driven into instability, small amplitude modulated (AM) microwave signals are amplified with the aid of injected white noise. The dependence of the signal amplification on the modulati

Cristiano Ciuti, Iacopo Carusotto

We present a full quantum theory for the dissipative dynamics of an optical cavity in the ultra-strong light-matter coupling regime, in which the vacuum Rabi frequency is comparable to the electronic transition frequency and the anti-resonant terms of the light-matter coupling play an important role. In particular, our model can be applied to the case of int

S. G. Magalhaes, F. M. Zimmer, C. J. Kipper, E. J. Callegari

The competition among spin glass (SG), antiferromagnetism (AF) and local pairing superconductivity (PAIR) is studied in a two-sublattice fermionic Ising spin glass model with a local BCS pairing interaction in the presence of an applied magnetic transverse field $Γ$. In the present approach, spins in different sublattices interact with a Gaussian random coup

S. G. Magalhaes, F. M. Zimmer, P. R. Krebs, B. Coqblin

The competition between spin glass, ferromagnetism and Kondo effect is analysed here in a Kondo lattice model with an inter-site random coupling $J_{ij}$ between the localized magnetic moments given by a generalization of the Mattis model which represents an interpolation between ferromagnetism and a highly disordered spin glass. Functional integral techniqu

W. A. Coish, Daniel Loss

The ability to perform high-precision one- and two-qubit operations is sufficient for universal quantum computation. For the Loss-DiVincenzo proposal to use single electron spins confned to quantum dots as qubits, it is therefore sufficient to analyze only single- and coupled double-dot structures, since the strong Heisenberg exchange coupling between spins

S. Yuan, H. De Raedt, S. Miyashita

Through numerical solution of the time-dependent Schrodinger equation, we demonstrate that magnetic chains with uniaxial anisotropy support stable structures, separating ferromagnetic domains of opposite magnetization. These structures, domain walls in a quantum system, are shown to remain stable if they interact with a spin wave. We find that a domain wall

Yoshihiko Togawa, Takashi Kimura, Ken Harada, Tetsuya Akashi

We investigate the current-excited magnetization dynamics in a narrow ferromagnetic Permalloy wire by means of Lorentz microscopy, together with the results of simultaneous transport measurements. A detailed structural evolution of the magnetization is presented as a function of the applied current density. Local structural deformation, bidirectional displac

O. E. Raichev, F. T. Vasko

Transient magnetotransport of two-dimensional electrons with partially-inverted distribution excited by an ultrashort optical pulse is studied theoretically. The time-dependent photoconductivity is calculated for GaAs-based quantum wells by taking into account the relaxation of electron distribution caused by non-elastic electron-phonon interaction and the r

D. Y. Vodolazov, F. M. Peeters, T. T. Hongisto, A. Yu. Arutyunov

A microscopic model is constructed which is able to describe multiple magnetic flux transitions as observed in recent ultra-low temperature tunnel experiments on an aluminum superconducting ring with normal metal - insulator - superconductor junctions [Phys. Rev. B \textbf{70}, 064514 (2004)]. The unusual multiple flux quantum transitions are explained by th

T. Zambelli, S. Goudeau, J. Lagoute, A. Gourdon

Because of its promising contribution to the bottom-up approach for nanofabrication of complex molecular architectures, self-organization is widely studied nowadays. Numerous studies have tackled supramolecular chirality or low-dimensional molecular nanostructures using in most cases small and rigid molecules adsorbed on metallic substrates. In this situatio

C. Cazorla, J. Boronat

We present a zero-temperature quantum Monte Carlo calculation of liquid $^4$He immersed in an array of confining potentials. These external potentials are centered in the lattice sites of a fcc solid geometry and, by modifying their well depth and range, the system evolves from a liquid phase towards a progressively localized system which mimics a solid phas

J. Hamrle, S. Blomeier, O. Gaier, B. Hillebrands

Magnetic anisotropies and magnetization reversal properties of the epitaxial Heusler compound Co$_2$Cr$_{0.6}$Fe$_{0.4}$Al (CCFA) deposited on Fe and Cr buffer layers are studied. Both samples exhibit a growth-induced fourfold anisotropy, and magnetization reversal occurs through the formation of stripy domains or 90 degree domains. During rotational magneto

Tomoya Ono, Kikuji Hirose

The electron-conduction properties of fullerene chains are examined by first-principles calculations based on the density functional theory. The conductivity of the C$_{60}$ dimer is low owing to the constraint of the junction of the molecules on electron conduction, whereas the C$_{60}$ monomer exhibits a conductance of $\sim$ 1 G$_0$. One of the three dege

M. A. Avila, K. Suekuni, K. Umeo, H. Fukuoka

The present controversy over the origin of glasslike thermal conductivity observed in certain crystalline materials is addressed by studies on single-crystal x-ray diffraction, thermal conductivity k(T) and specific heat Cp(T) of carrier-tuned Ba8Ga16X30 (X = Ge, Sn) clathrates. These crystals show radically different low-temperature k(T) behaviors depending

Z. P. Yin, S. Y. Savrasov, W. E. Pickett

Linear response methods are applied to identify the increase in electron-phonon coupling in elemental yttrium that is responsible for its high superconducting critical temperature Tc, which reaches nearly 20 K at 115 GPa. While the evolution of the band structure and density of states is smooth and seemingly modest, there is strong increase in the 4d content

Mukunda P. Das, Frederick Green, Jagdish S. Thakur

We remark on some delicate points that attend the physical meaning of intrinsic device resistance.

Xiang Xia, Robert J. Silbey

The nature of fluorescence intermittency for semiconductor quantum dots (QD) and single molecules (SM) is proposed as a manifestation of Anderson localization. The power law like distribution for the \emph{on} time is explained as due to the interaction between QD/SM with a random environment. In particular, we find that the \emph{on}-time probability distri

Stefan Hilbert, Jörn Dunkel

We calculate exactly both the microcanonical and canonical thermodynamic functions (TDFs) for a one-dimensional model system with piecewise constant Lennard-Jones type pair interactions. In the case of an isolated $N$-particle system, the microcanonical TDFs exhibit (N-1) singular (non-analytic) microscopic phase transitions of the formal order N/2, separati

Michael Patra, Marja T. Hyvonen, Emma Falck, Mohsen Sabouri-Ghomi

Typical biomolecular systems such as cellular membranes, DNA, and protein complexes are highly charged. Thus, efficient and accurate treatment of electrostatic interactions is of great importance in computational modelling of such systems. We have employed the GROMACS simulation package to perform extensive benchmarking of different commonly used electrostat

Zhiyuan Li, Q. Daniel Wang, Judith A. Irwin, Tara Chaves

We present an XMM-Newton observation of the massive edge-on Sb galaxy NGC 2613. We discover that this galaxy contains a deeply embedded active nucleus with a 0.3-10 keV luminosity of 3.3x10^40 erg/s and a line-of-sight absorption column of 1.2x10^23 cm^-2. Within the 25 mag/arcsec^2 optical B-band isophote of the galaxy, we detect an additional 4 sources wit

Nicholas M. Ball, Robert J. Brunner, Adam D. Myers, David Tcheng

We provide classifications for all 143 million non-repeat photometric objects in the Third Data Release of the Sloan Digital Sky Survey (SDSS) using decision trees trained on 477,068 objects with SDSS spectroscopic data. We demonstrate that these star/galaxy classifications are expected to be reliable for approximately 22 million objects with r < ~20. The ge

Christian Leipski, Heino Falcke, Nicola Bennert, Susanne Huettemeister

We investigate the radio emitting structures of radio-quiet active galactic nuclei with an emphasis on radio-quiet quasars to study their connection to Seyfert galaxies. We present and analyse high-sensitivity VLA radio continuum images of 14 radio-quiet quasars and six Seyfert galaxies. Many of the low redshift radio-quiet quasars show radio structures that

Paula Szkody, Thomas E. Harrison, Richard M. Plotkin, Steve B. Howell

Low state optical photometry of EF Eri during an extended low accretion state combined with GALEX near and far UV time-resolved photometry reveals a source of UV flux that is much larger than the underlying 9500K white dwarf, and that is highly modulated on the orbital period. The near UV and optical light curves can be modeled with a 20,000K spot but no spo

Gregory Rudnick, Ivo Labbe, Natascha M. Foerster Schreiber, Stijn Wuyts

(Abridged) We present the evolution of the volume averaged properties of the rest-frame optically luminous galaxy population to z~3, determined from four disjoint deep fields with optical to near-infrared wavelength coverage. We select galaxies above a rest-frame V-band luminosity of 3x10^10 Lsol and characterize their rest-frame UV through optical propertie

A. A. Coley, N. Pelavas

We discuss the averaging problem in general relativity, using the form of the macroscopic gravity equations in the case of spherical symmetry in volume preserving coordinates. In particular, we calculate the form of the correlation tensor under some reasonable assumptions on the form for the inhomogeneous gravitational field and matter distribution. On cosmo

Toshiya Ueta

We present the far-infrared (IR) maps of a bipolar planetary nebula (PN), NGC 650, at 24, 70, and 160 micron taken with the Multiband Imaging Photometer for Spitzer (MIPS) on-board the Spitzer Space Telescope. While the two-peak emission structure seen in all MIPS bands suggests the presence of a near edge-on dusty torus, the distinct emission structure betw

N. P. H. Nesvadba, M. D. Lehnert, F. Eisenhauer, A. Gilbert

To explain the properties of the most massive low-redshift galaxies and the shape of their mass function, recent models of galaxy evolution include strong AGN feedback to complement starburst-driven feedback in massive galaxies. Using the near-infrared integral-field spectrograph SPIFFI on the VLT, we searched for direct evidence for such a feedback in the o

Artyom V. Yurov, Prado Martin Moruno, Pedro F. Gonzalez-Diaz

This paper contains a detailed discussion on new cosmic solutions describing the early and late evolution of a universe that is filled with a kind of dark energy that may or may not satisfy the energy conditions. The main distinctive property of the resulting space-times is that they make to appear twice the single singular events predicted by the correspond

J. S. Sanders

We present a new technique for choosing spatial regions for X-ray spectroscopy, called &#34;contour binning&#34;. The method chooses regions by following contours on a smoothed image of the object. In addition we re-explore a simple method for adaptively smoothing X-ray images according to the local count rate, we term &#34;accumulative smoothing&#34;, which

N. P. H. Nesvadba, M. D. Lehnert, F. Eisenhauer, R. Genzel

Using the near-infrared integral-field spectrograph SPIFFI on the VLT, we have studied the spatially-resolved dynamics in the z=3.2 strongly lensed galaxy 1E0657-56 ``arc+core&#39;&#39;. The lensing configuration suggests that the high surface brightness ``core&#39;&#39; is the M=20 magnified central 1 kpc of the galaxy (seen at a spatial resolution of about

C. Guidorzi, F. Frontera, E. Montanari, F. Rossi

From a sample of 32 GRBs with known redshift (Guidorzi et al. 2005) and then a sample of 551 BATSE GRBs with derived pseudo-redshift (Guidorzi 2005), the time variability/peak luminosity correlation (V vs. L) found by Reichart et al. (2001) was tested. For both samples the correlation is still found but less relevant due to a much higher spread of the data.

John P. Wisniewski, Karen S. Bjorkman, ;

We present B, V, R, and H alpha photometry of 8 clusters in the Small Magellanic Cloud, 5 in the Large Magellanic Cloud, and 3 Galactic clusters, and use 2 color diagrams (2-CDs) to identify candidate Be star populations in these clusters. We find evidence that the Be phenomenon is enhanced in low metallicity environments, based on the observed fractional ea

Abhijit Bhattacharyya, Sanjay K. Ghosh, Partha S. Joardar, Ritam Mallick

The conversion of neutron matter to strange matter in a neutron star have been studied as a two step process. In the first step, the nuclear matter gets converted to two flavour quark matter. The conversion of two flavour to three flavour strange matter takes place in the second step. The first process is analysed with the help of equations of state and hydr

K. Geissler, E. Masciadri

In this paper we present the characterization of all the principal meteorological parameters (wind speed and direction, pressure, absolute and potential temperature) extended over 25 km from the ground and over two years (2003 and 2004) above the Antarctic site of Dome C. The data set is composed by &#39;analyses&#39; provided by the General Circulation Mode

C. P. Haines, F. La Barbera, A. Mercurio, P. Merluzzi

We examine the origins of the bimodality observed in the global properties of galaxies around a stellar mass of 3x10^10 M_sun by comparing the environmental dependencies of star-formation for the giant and dwarf galaxy populations. The Sloan Digital Sky Survey DR4 spectroscopic dataset is used to produce a sample of galaxies in the vicinity of the superclust

Sergio del Campo, Ramon Herrera, German Olivares, Diego Pavon

The coincidence problem of late cosmic acceleration is a serious riddle in connection with our understanding of the evolution of the Universe. In this paper we show that an interaction between the dark energy component (either phantom or quintessence) and dark matter can alleviate it. In this scenario the baryon component is independently conserved. This gen

Slavek M. Rucinski, Hilmar Duerbeck

Radial-velocity measurements and sine-curve fits to the orbital velocity variations are presented for nine contact binaries, V1464 Aql, V759 Cen, DE Oct, MW Pav, BQ Phe, EL Aqr, SX Crv, VZ Lib, GR Vir; for the first five among these, our observations are the first available radial velocity data. Among three remaining radial velocity variables, CE Hyi is a kn

A. P. Hatzes, W. D. Cochran, M. Endl E. W. Guenther, S. H. Saar

We present precise stellar radial velocity measurements for the K giant star Beta Gem spanning over 25 years. These data show that the long period low amplitude radial velocity variations found by Hatzes & Cochran (1993) are long-lived and coherent. An examination of the Ca II K emission, spectral line shapes from high resolution data (R = 210,000), and Hipp

A. Asensio Ramos

It is shown that the two-part Minimum Description Length Principle can be used to discriminate among different models that can explain a given observed dataset. The description length is chosen to be the sum of the lengths of the message needed to encode the model plus the message needed to encode the data when the model is applied to the dataset. It is veri

W. Zima, D. Wright, J. Bentley, P. L. Cottrell

We present a mode identification based on new high-resolution time-series spectra of the non-radially pulsating Delta Scuti star FG~Vir (HD 106384, V = 6.57, A5V). From 2002 February to June a global Delta Scuti Network (DSN) campaign, utilizing high-resolution spectroscopy and simultaneous photometry has been conducted for FG~Vir in order to provide a theor

Satoki Matsushita, Masao Saito, Kazushi Sakamoto, Todd R. Hunter

We report the measurement results and compensation of the antenna elevation angle dependences of the Sub-millimeter Array (SMA) antenna characteristics. Without optimizing the subreflector (focus) positions as a function of the antenna elevation angle, antenna beam patterns show lopsided sidelobes, and antenna efficiencies show degradations. The sidelobe lev

W. Zima

We present the Fourier parameter fit method, a new method for spectroscopically identifying stellar radial and non-radial pulsation modes based on the high-resolution time-series spectroscopy of absorption-line profiles. In contrast to previous methods this one permits a quantification of the statistical significance of the computed solutions. The applicatio

Tarun Souradeep

Observational Cosmology has indeed made very rapid progress in recent years. The ability to quantify the universe has largely improved due to observational constraints coming from structure formation Measurements of CMB anisotropy and, more recently, polarization have played a very important role. Besides precise determination of various parameters of the `s

Amedeo Balbi, Paolo Natoli, Nicola Vittorio

The study of cosmic microwave background (CMB) polarization is still in a pioneering stage, but promises to bring a huge advancement in cosmology in the near future, just as high-accuracy observations of the anisotropies in the total intensity of the CMB revolutionized our understanding of the universe in the past few years. In this contribution, we outline

Ludovic Sauge, Gilles Henri

Most of current models of TeV blazars emission assume a Synchrotron Self-Compton mechanism where relativistic particles emit both synchrotron radiation and Inverse Compton photons. For sake of simplicity, these models usually consider only steady state emission. The spectral features are thus only related to the shape of the particle distribution, and do not

Xiang-Dong Li

The recent discovery of rotating radio transients and the quasi-periodicity of pulsar activity in the radio pulsar PSR B1931$+$24 has challenged the conventional theory of radio pulsar emission. Here we suggest that these phenomena could be due to the interaction between the neutron star magnetosphere and the surrounding debris disk. The pattern of pulsar em

S. Kuch

The KM3NeT project is a common European effort for the design of a km3-scale deep-sea neutrino telescope in the Mediterranean. For the upcoming Design Study simulations have been done using modified ANTARES software. Several concepts and ideas have been tested for their merits and feasibility.

D. M. Harrington, J. R. Kuhn, K. Whitman

We designed, built, and calibrated a new spectropolarimeter for the HiVIS spectrograph (R 12000-49000) on the AEOS telescope. We also did a polarization calibration of the telescope and instrument. We will introduce the design and use of the spectropolarimeter as well as a new data reduction package we have developed, then discuss the polarization calibratio

A. S. Almgren, J. B. Bell, C. A. Rendleman, M. Zingale

The convective period leading up to a Type Ia supernova (SN Ia) explosion is characterized by very low Mach number flows, requiring hydrodynamical methods well-suited to long-time integration. We continue the development of the low Mach number equation set for stellar scale flows by incorporating the effects of heat release due to external sources. Low Mach