April 2006 arXiv papers — page 3

Denis Auroux, Ludmil Katzarkov

Every compact symplectic 4-manifold can be realized as a branched cover of the complex projective plane branched along a symplectic curve with cusp and node singularities; the covering map is induced by a triple of sections of a "very ample" line bundle. In this paper, we give an explicit formula describing the behavior of the braid monodromy invaria

Mercedes Arriojas, Yaozhong Hu, Salah-Eldin Mohammed, Gyula Pap

This article is a sequel to [A.H.M.P]. In [A.H.M.P], we develop an explicit formula for pricing European options when the underlying stock price follows a non-linear stochastic delay equation with fixed delays in the drift and diffusion terms. In this article, we look at models of the stock price described by stochastic functional differential equations with

Mercedes Arriojas, Yaozhong Hu, Salah-Eldin Mohammed, Gyula Pap

In this article we develop an explicit formula for pricing European options when the underlying stock price follows a non-linear stochastic differential delay equation (sdde). We believe that the proposed model is sufficiently flexible to fit real market data, and is yet simple enough to allow for a closed-form representation of the option price. Furthermore

David Larson, Eckart Schulz, Darrin Speegle, Keith Taylor

We consider two classes of actions on $\mathbb{R}^n$ - one continuous and one discrete. For matrices of the form $A = e^B$ with $B \in M_n(\R)$, we consider the action given by $γ\to γA^t$. We characterize the matrices $A$ for which there is a cross-section for this action. The discrete action we consider is given by $γ\to γA^k$, where $A\in GL_n(\R)$. We ch

Cedric Lecouvey

The tensor powers of the vector representation associated to an infinite rank quantum group decompose into irreducible components with multiplicities independant of the infinite root system considered. Although the irreducible modules obtained in this way are not of highest weight, they admit a crystal basis and a canonical basis. This permits in particular

Tristan Riviere, Michael Struwe

Via Gauge theory, we give a new proof of partial regularity for harmonic maps in dimension m>2 into arbitrary targets. This proof avoids the use of adapted frames and permits to consider targets of "minimal" C^2 regularity. The proof we present moreover extends to a large class of elliptic systems of quadratic growth.

Yusuf Civan, Ergun Yalcin

A vertex coloring of a simplicial complex $Δ$ is called a linear coloring if it satisfies the property that for every pair of facets $(F_1, F_2)$ of $Δ$, there exists no pair of vertices $(v_1, v_2)$ with the same color such that $v_1\in F_1\backslash F_2$ and $v_2\in F_2\backslash F_1$. We show that every simplicial complex $Δ$ which is linearly colored wit

Wicher P. Bergsma

A possible drawback of the ordinary correlation coefficient $ρ$ for two real random variables $X$ and $Y$ is that zero correlation does not imply independence. In this paper we introduce a new correlation coefficient $ρ^*$ which assumes values between zero and one, equalling zero iff the two variables are independent and equalling one iff the two variables a

Samy Skander Bahoura

We proove some inequalities concerning the product, sup * inf for some elliptic operators of order 2 and 4. Using those inequalities and the concentration phenomena we can describe the asymptotic behavior of those PDE solutions.

Massimo Fornasier, Laura Gori

This paper concerns with iterative schemes for the perfect reconstruction of functions belonging to multiresolution spaces on bounded manifolds from nonuniform sampling. The schemes have optimal complexity in the sense that the computational cost to achieve a certain fixed accuracy is proportional to the computed quantity. Since the iterations converge unifo

P. M. Sołtan

We introduce the analog of Bohr compactification for discrete quantum groups on C*-algebra level. The cases of unimodular and general C*-algebraic discrete quantum groups are treated separately. The passage from the former case to the latter is done with help of the concept of canonical Kac quotient for compact quantum groups\footnotemark. Several examples a

P. M. Sołtan

We construct quantum "az+b" groups for new values of the deformation parameter. Along the way we introduce new special functions and study their analytic properties as well as analyze the commutation relations determined by the choice of parameter.

P. M. Sołtan

We investigate the problem whether a given multiplier of a tensor product of two algebras belongs to the tensor product of multiplier algebras. We give a characterization of such multipliers in the case when one of the algebras is the algebra of functions on a discrete quantum group.

David R. Larson

We give a detailed description of the local commutant approach to wavelet theory using operator algebraic methods. We include a new result on interpolation pairs of wavelet sets: Every pair in the generalized Journe family of wavelet sets is an interpolation pair. In the last section, we give a discussion of several open problems on wavelets and frame-wavele

P. M. Sołtan

Given a discrete quantum group A we construct a certain Hopf *-algebra AP which is a unital *-subalgebra of the multiplier algebra of A. The structure maps for AP are inherited from M(A) and thus the construction yields a compactification of A which is analogous to the Bohr compactification of a locally compact group. This algebra has the expected universal

P. M. Sołtan

It is shown that although the spectrum of the analytic generator of a one--parameter group of isometries of a Banach space may be equal to the whole complex plane, a simple operation of ampliating the analytic generator onto its graph locates its spectrum in the positive halfline.

David R. Larson

A wavelet is a special case of a vector in a separable Hilbert space that generates a basis under the action of a collection, or system, of unitary operators. We will describe the operator-interpolation approach to wavelet theory using the local commutant of a system. This is really an abstract application of the theory of operator algebras to wavelet theory

P. M. Sołtan, S. L. Woronowicz

We propose a weaker condition for multiplicative unitary operators related to quantum groups, than the condition of manageability introduced by S.L. Woronowicz. We prove that all the main results of the theory of manageable multiplicative unitaries remain true under this weaker condition. We also show that multiplicative unitaries arising naturally in the co

W. Pusz, P. M. Sołtan

The formula for all unitary representations of the quantum "az+b" group for a real deformation parameter is given. The description involves the quantum exponential function introduced by Woronowicz.

Emanuel Milman

We develop a technique using dual mixed-volumes to study the isotropic constants of some classes of spaces. In particular, we recover, strengthen and generalize results of Ball and Junge concerning the isotropic constants of subspaces and quotients of L_p and related spaces. An extension of these results to negative values of p is also obtained, using genera

Emanuel Milman

We study the structures of two types of generalizations of intersection-bodies and the problem of whether they are in fact equivalent. Intersection-bodies were introduced by Lutwak and played a key role in the solution of the Busemann-Petty problem. A natural geometric generalization of this problem considered by Zhang, led him to introduce one type of gener

Ehud Hrushovski, David Kazhdan

We develop a theory of integration over valued fields of residue characteristic zero. In particular we obtain new and base-field independent foundations for integration over local fields of large residue characteristic, extending results of Denef,Loeser, Cluckers. The method depends on an analysis of definable sets up to definable bijections. We obtain a pre

S. Bellucci, S. Krivonos, A. Shcherbakov

We explicitly construct N=4 worldline supersymmetric minimal off-shell actions for five options of 1/2 partial spontaneous breaking of $N=8, d=1$ Poincaré supersymmetry. We demonstrate that the action for the N=4 Goldstone supermultiplet with four fermions and four auxiliary components is a universal one. The remaining actions for the Goldstone supermultiple

J. Ambjorn, J. Jurkiewicz, R. Loll

The method of four-dimensional Causal Dynamical Triangulations provides a background-independent definition of the sum over geometries in quantum gravity, in the presence of a positive cosmological constant. We present the evidence accumulated to date that a macroscopic four-dimensional world can emerge from this theory dynamically. Using computer simulation

Kazumi Okuyama, Gordon W. Semenoff

The matrix models which are conjectured to compute the circle Wilson loop and its correlator with chiral primary operators are mapped onto normal matrix models. A fermion droplet picture analogous to the well-known one for chiral primary operators is shown to emerge in the large N limit. Several examples are computed. We find an interesting selection rule fo

James Gray, Yang-Hui He, Vishnu Jejjala, Brent D. Nelson

Using techniques of algorithmic algebraic geometry, we present a new and efficient method for explicitly computing the vacuum space of N=1 gauge theories. We emphasize the importance of finding special geometric properties of these spaces in connecting phenomenology to guiding principles descending from high-energy physics. We exemplify the method by address

F. Larios, R. Martinez, M. A. Perez

We survey the flavor-changing neutral couplings (FCNC) of the top quark predicted by some extensions of the Standard Model: THDM, SUSY, L-R symmetric, TC2, 331, and models with extra quarks. Since the expected sensitivity of the LHC and ILC for the tcV (V=γ,g,Z) and tcH couplings is of order of a few percent, we emphasize the importance of any new physics ef

Ernesto A. Matute

We consider a scenario in which the discrete weak symmetry between quarks and leptons is extended to the weak force by introducing exotic partners. We conjecture that there exists a hidden discrete symmetry $\tilde{P}$, defining a $Z_2$ group, between standard and exotic quarks and leptons. The unified model $SU(3)_{q} \times SU(3)_{\tilde{q}} \times SU(2)_{

E. Accomando

We have given a first application of the Axial gauge a` la Dams and Kleiss to the Standard Model (SM) physics at the LHC. We have focused on the issue of providing a well-behaved signal definition in presence of potentially strong gauge cancellations at high energies. As a first illustration, we have analysed the production of WZ vector-boson pairs, which gi

R. Jeannerot

${\rm B - L}$ cosmic strings form in a wide class of theories beyond the Standard Model which contain a ${\rm U}(1)_{\rm B - L}$ gauge symmetry. They can form at the end of hybrid inflation and explain, together with inflation, the Cosmic Microwave Background anisotropies and the formation of large scale structure. They can produce Cold Dark Matter in the fo

Yin-Jie Zhang, Huan-Ching Chiang, Peng-Nian Shen, Bing-Song Zou

Using the potentials derived from vector-meson-exchanges, the $K\bar K$, $DK$, $B\bar K$, $D\bar D$, $B\bar B$, $BD$, $\bar D K$, $BK$ and $B\bar D$ systems are studied. Possible S-wave bound-states of two pseudoscalar mesons are discussed. We find that systems of $DB$, $D\bar D$, $B\bar B$ and $DK$ with isospin 0 are likely to form S-wave bound states via s

Rachel Jeannerot

The cosmological consequences of particle physics grand unified theories (GUTs) are studied. Cosmological models are implemented in realistic particle physics models. Models consistent from both particle physics and cosmological considerations are selected. (...)

H. van Hees, R. Rapp

We confront different models for medium modifications of the electromagnetic correlation function to recent dimuon spectra from the NA60 collaboration for central In-In collisions at the CERN-SPS. In the low-mass region (M \lesssim 1.0 GeV), we evaluate medium modifications of the spectral properties of ρ-, ω- and ϕ-mesons. In the intermediate-mass region (M

V. S Pantuev

We demonstrate that the existence of a finite formation time of strongly interacting plasma in nuclear collisions at RHIC is an inavitable conclusion from recent experimental data. The most striking feature of the experimental data - an absense of absorption of high transverse momentum pions in the rection plane direction for mid-peripheral collisions - poin

C. Hagedorn, M. Lindner, F. Plentinger

We consider the standard model (SM) extended by the flavor symmetry D5 and search for a minimal model leading to viable phenomenology. We find that it contains four Higgs fields apart from the three generations of fermions whose left- and left-handed conjugate parts do not transform in the same way under D5. We provide two numerical fits for the case of Dira

Anders Tranberg, Jan Smit

Cold electroweak baryogenesis was proposed as a scenario to bypass generic problems of electroweak baryogenesis within the Standard Model. In this scenario, baryogenesis takes place during an electroweak symmetry breaking transition, which is also responsible for preheating after inflation. In the simplest modelling of the scenario, only two parameters remai

V. Kubarovsky, M. Battaglieri, R. De Vita, J. Goett

The reaction $γp \to pK^+K^-$ was studied at Jefferson Lab with photon energies from 1.8 to 3.8 GeV using a tagged photon beam. The goal was to search for a $Θ^{++}$ pentaquark, a narrow doubly charged baryon state having strangeness S=+1 and isospin I=1, in the $pK^+$ invariant mass spectrum. No statistically significant evidence of a $Θ^{++}$ was found. Up

H1 Collaboration

A search for a narrow baryonic resonance decaying to $K^0_s p$ or $K^0_s \bar p$ is carried out in deep inelastic ep scattering with the H1 detector at HERA. Such a resonance could be a strange pentaquark \thplns, evidence for which has been reported by several experiments. The $K^0_s p$ and $K^0_s \bar p$ invariant mass distributions presented here do not s

B. D. Yabsley

The new Belle phi_3/gamma measurement arXiv:hep-ex/0604054, based on Dalitz analysis of D -> Kshort pi+ pi- in B+- -> D(*) K(*)+- decays, uses likelihood ratio ordering to set confidence intervals in phi_3 and the r,delta parameters. This is different to the choice made by BaBar in PRL 95, 121802 (2005) and arXiv:hep-ex/0507101, and requires additional compu

The Belle Collaboration, A. Poluektov

We present a measurement of the unitarity triangle angle phi_3 using a Dalitz plot analysis of the K0_S pi+ pi- decay of the neutral D meson from the B+- -> D(*)K(*)+- process. The method employs the interference between D0 and D0bar to extract the angle phi_3, strong phase Delta and the ratio r of suppressed and allowed amplitudes. We apply this method to a

W. Zimdahl, J. C. Fabris

Perturbations in a Chaplygin gas, characterized by an equation of state $p = -A/ρ$, may acquire non-adiabatic contributions if spatial variations of the parameter $A$ are admitted. This feature is shown to be related to a specific internal structure of the Chaplygin gas. We investigate how perturbations of this type modify the adiabatic sound speed. A reduct

C. Peralta, A. Melatos, M. Giacobello, A. Ooi

The gravitational wave signal generated by global, nonaxisymmetric shear flows in a neutron star is calculated numerically by integrating the incompressible Navier--Stokes equation in a spherical, differentially rotating shell. At Reynolds numbers $\Rey \gsim 3 \times 10^{3}$, the laminar Stokes flow is unstable and helical, oscillating Taylor--Görtler vorti

Sergio Caracciolo, Davide Fichera, Andrea Sportiello

2-dimensional Matching Problem, which requires to find a matching of left- to right-vertices in a balanced $2n$-vertex bipartite graph, is a well-known polynomial problem, while various variants, like the 3-dimensional analogoue (3DM, with triangles on a tripartite graph), or the Hamiltonian Circuit Problem (HC, a restriction to ``unicyclic'' matchin

Jacek Becla, Andrew Hanushevsky, Sergei Nikolaev, Ghaleb Abdulla

The 3.2 giga-pixel LSST camera will produce approximately half a petabyte of archive images every month. These data need to be reduced in under a minute to produce real-time transient alerts, and then added to the cumulative catalog for further analysis. The catalog is expected to grow about three hundred terabytes per year. The data volume, the real-time tr

W. J. Padilla, M. T. Aronsson, C. Highstrete, Mark Lee

We present a new class of artificial materials which exhibit a tailored response to the electrical component of electromagnetic radiation. These electric metamaterials (EM-MMs) are investigated theoretically, computationally, and experimentally using terahertz time-domain spectroscopy. These structures display a resonant response including regions of negativ

Satoshi Kokado, Nobuhisa Fujima, Kikuo Harigaya, Hisashi Shimizu

In order to propose a ferromagnet exhibiting highly spin-polarized transport, we theoretically analyzed the spin polarization ratio of the conductivity of the bulk Fe$_4$N with a perovskite type structure, in which N is located at the body center position of fcc-Fe. The spin polarization ratio is defined by $P = (σ_\uparrow - σ_\downarrow) / (σ_\uparrow + σ_

M. Gich, C. Frontera, A. Roig, E. Taboada

The crystal and magnetic structures of the orthorhombic e-Fe2O3 have been studied by simultaneous Rietveld refinement of X-ray and neutron powder diffraction data in combination with Mossbauer spectroscopy, as well as magnetisation and heat capacity measurements. It has been found that above 150 K the e-Fe2O3 polymorph is a collinear ferrimagnet with the mag

Daniel R. Spiegel, Elliot R. Johnson, Skyler R. Saucedo

We report a liquid-crystal pattern-formation experiment in which we break the lateral (translational) symmetry of a nematic medium with a laser-induced thermal gradient. The work is motivated by an improved measurement (reported here) of the temperature dependence of the electroconvection threshold voltage in planar-nematic 4-methoxybenzylidene-4-butylanilin

Francesco Guerra

In previous work, we have developed a simple method to study the behavior of the Sherrington-Kirkpatrick mean field spin glass model for high temperatures, or equivalently for high external fields. The basic idea was to couple two different replicas with a quadratic term, trying to push out the two replica overlap from its replica symmetric value. In the cas

Christian Klinke, Erik Delvigne, Johannes V. Barth, Klaus Kern

We have studied nickel, gold, and ferritin coatings on catalytically grown multiwall carbon nanotubes, as well as the generation of secondary nanotubes by resubmitting the decorated nanotubes to the chemical vapor deposition process. Nickel layers sputtered on nanotubes show a stronger interaction with the nanotube walls than gold coatings. At ambient temper

M. Bejas, A. Greco, A. Foussats

Using a recently developed perturbative approach, which considers Hubbard operators as fundamental excitations, we have performed electronic self-energy and spectral function calculations for the $t-J$ model on the square lattice. We have found that the spectral functions along the Fermi surface are isotropic, even close to the critical doping where the $d$-

F. Pollmann, J. J. Betouras, E. Runge

We map certain highly correlated electron systems on lattices with geometrical frustration in the motion of added particles or holes to the spatial defect-defect correlations of dimer models in different geometries. These models are studied analytically and numerically. We consider different coverings for four different lattices: square, honeycomb, triangula

R. J. Birgeneau, C. Stock, J. M. Tranquada, K. Yamada

A review is presented of the static and dynamic magnetic properties of hole-doped cuprate superconductors measured with neutron scattering. A wide variety of experiments are described with emphasis on the monolayer La_{2-x}(Sr,Ba)_{x}CuO_{4} and bilayer YBa_{2}Cu_{3}O_{6+x} cuprates. At zero hole doping, both classes of materials are antiferromagnetic insula

F. Pollmann, P. Fulde

We address the question whether features known from quantum chromodynamics (QCD) can possibly also show up in solid-state physics. It is shown that spinless fermions of charge $e$ on a checkerboard lattice with nearest-neighbor repulsion provide for a simple model of confined fractional charges. After defining a proper vacuum the system supports excitations

J. Fink, A. Koitzsch, J. Geck, V. Zabolotnyy

Angle-resolved photoemission spectroscopy (ARPES) is used to study the spectral function of the optimally doped high-T$_c$ superconductor (Bi,Pb)$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ in the vicinity of the antinodal point in the superconducting state. Using a parameterized self-energy function, it was possible to describe both the coherent and the incoherent spectral

J. Marro, J. J. Torres, J. M. Cortes, B. Wemmenhove

We present exact results, as well as some illustrative Monte Carlo simulations, concerning a stochastic network with weighted connections in which the fraction of nodes that are dynamically synchronized is a parameter. This allows one to describe from single-node kinetics to simultaneous updating of all the variables at each time unit. An example of the form

T. Srokowski, A. Kaminska

We consider a Markovian jumping process which is defined in terms of the jump-size distribution and the waiting-time distribution with a position-dependent frequency, in the diffusion limit. We assume the power-law form for the frequency. For small steps, we derive the Fokker-Planck equation and show the presence of the normal diffusion, subdiffusion and sup

V. Garbuio, M. Cascella, L. Reining, R. Del Sole

We present ab-initio calculations of the excited state properties of liquid water in the framework of Many-Body Green's function formalism. Snapshots taken from molecular dynamics simulations are used as input geometries to calculate electronic and optical spectra, and the results are averaged over the different configurations. The optical absorption spe

Nitya Nath Shukla, R. Prasad

A first-principles electronic structure study of orthorhombic, monoclinic and rhombohedral LiMnO$_{2}$ has been carried out using the full-potential linearized augmented plane-wave method. The exchange and correlations have been treated within the local spin-density approximation (LSDA) and the LSDA+U methods. In the LSDA, the stable ground state is antiferr

Andrea Gabrielli, Andrea Baldassarri, Miguel A. Munoz, Bernard Sapoval

We present a two-dimensional theoretical model for the slow chemical corrosion of a thin film of a disordered solid by suitable etching solutions. This model explain different experimental results showing that the corrosion stops spontaneously in a situation in which the concentration of the etchant is still finite while the corrosion surface develops clear

J. I. Climente, A. Bertoni, G. Goldoni, E. Molinari

We investigate charge relaxation rates due to acoustic phonons in weakly-confined quantum dot systems, including both deformation potential and piezoelectric field interactions. Single-electron excited states lifetimes are calculated for single and coupled quantum dot structures, both in homonuclear and heteronuclear devices. Piezoelectric field scattering i

S. J. van der Molen, N. Tombros, B. J. van Wees

We discuss the influence of the magneto-coulomb effect (MCE) on the magnetoconductance of spin valve devices. We show that MCE can induce magnetoconductances of several per cents or more, dependent on the strength of the coulomb blockade. Furthermore, the MCE-induced magnetoconductance changes sign as a function of gate voltage. We emphasize the importance o

Hendry Izaac Elim, Jianying Ouyang, Suat Hong Goh, Wei Ji

By using nanosecond laser pulses at 532-nm wavelength, we have intensively studied the optical limiting and nonlinear optical properties of some new composites which consist of mono-functional 1,2-dihydro-1,2-methanofullerene[60]-61-carboxylic acid (FCA), multifunctional fullerenol, and supramolecular C60(HNC4H8NCH3)9 - containing polymers. The optical limit

Hendry Izaac Elim, Wei Ji, Furong Zhu

Optical Kerr nonlinearity (n2) in n-type indium tin oxide (ITO) films coated on glass substrates has been measured using Z-scans with 200-fs laser pulses at wavelengths ranging from 720 to 780 nm. The magnitudes of the measured nonlinearity in the ITO films were found to be dependent on the carrier concentration with a maximum n2-value of 4.1 x 10-5 cm2/GW a

Hendry I. Elim, Jian Yang, Jim-Yang Lee, Jun Mi

Saturable and reverse saturable absorption at longitudinal surface plasmon resonance (SPR) in gold nanorods (Au NRs) have been observed using Z-scan and transient absorption techniques with femtosecond laser pulses. At lower excitation irradiances, the wavelength dispersion of saturable absorption has been determined near the longitudinal mode of SPR with a

Heinz-Jürgen Schmidt, Johannes Richter, Roderich Moessner

At the magnetic saturation field, certain frustrated lattices have a class of states known as "localized multi-magnon states" as exact ground states. The number of these states scales exponentially with the number $N$ of spins and hence they have a finite entropy also in the thermodynamic limit $N\to \infty$ provided they are sufficiently linearly in

S. Yoshii, S. Sonoda, T. Yamamoto, T. Kashiwagi

A GaN film doped with 8.2 % Mn was grown by the molecular-beam-epitaxy technique. Magnetization measurements show that this highly Mn-doped GaN film exhibits ferromagnetism above room temperature. It is also revealed that the high-temperature ferromagnetic state is significantly suppressed below 10 K, accompanied by an increase of the electrical resistivity

Masatosi Oka, Masanori Ichioka, Kazushige Machida

We investigate how the macroscopic spatial structure of broken inversion symmetry manifests in noncentrosymmetric superconductors, by the microscopic broken inversion symmetry of the crystal structure. Based on the time-dependent Ginzburg-Landau theory including the Pauli paramagnetic effect and the Rashba interaction, we demonstrate that the centrosymmetric

Anders M. N. Niklasson, C. J. Tymczak, Matt Challacombe

We present a time-reversible Born-Oppenheimer molecular dynamics scheme, based on self-consistent Hartree-Fock or density functional theory, where both the nuclear and the electronic degrees of freedom are propagated in time. We show how a time-reversible adiabatic propagation of the electronic degrees of freedom is possible despite the non-linearity and inc

L. Francis, J. -M. Friedt, C. Zhou, P. Bertrand

We show the theoretical and experimental combination of acoustic and optical methods for the in situ quantitative evaluation of the density, the viscosity and the thickness of soft layers adsorbed on chemically tailored metal surfaces. For the highest sensitivity and an operation in liquids, a Love mode surface acoustic wave (SAW) sensor with a hydrophobized

Adam Rycerz, Jozef Spalek

We discuss the applied magnetic field dependence of the absorption of microwaves by a 3-dimensional array up to 30x30x30 Josephson junctions with random parameters including the resistivity, capacity and inductance of each junction. The numerical simulation results for the networks show characteristic microwave absorption anomalies observed in the ceramic sa

T. J. Davidge, Joseph B. Jensen, K. A. G. Olsen

Images obtained with NIRI on the Gemini North telescope are used to investigate the photometric properties of the central regions of M31 in the 3 - 5 micron wavelength range. The light distribution in the central arcsecond differs from what is seen in the near-infrared in the sense that the difference in peak brigh tness between P1 and P2 is larger in M'

J. Machalski, M. Jamrozy, S. Zola, D. Koziel

Our sample of giant radio-source candidates, published in Paper I (Machalski et al. 2001), is updated and supplemented with further radio and optical data. In this paper we present: (i) newly detected host galaxies, their photometric magnitude, and redshift estimate for the sample sources not identified yet, (ii) optical spectra and spectroscopic redshift fo

L. O. Kerber, B. X. Santiago

We used the deep colour-magnitude diagrams (CMDs) of five rich LMC clusters (NGC1805, 1818, 1831, 1868, and Hodge14) observed with HST/WFPC2 to derive their present day mass function (PDMF) and its variation with position within the cluster. The PDMF was parameterized as a power law in the available main-sequence mass range of each cluster, typically 0.9 <~

Joey Shapiro Key, Neil J. Cornish, David N. Spergel, Glenn D. Starkman

Clues to the shape of our Universe can be found by searching the CMB for matching circles of temperature patterns. A full sky search of the CMB, mapped extremely accurately by NASA&#39;s WMAP satellite, returned no detection of such matching circles and placed a lower bound on the size of the Universe at 24 Gpc. This lower bound can be extended by optimally

Ian A. Bonnell, Matthew R. Bate

Competitive accretion, a process to explain the origin of the IMF, occurs when stars in a common gravitational potential accrete from a distributed gaseous component. We show that concerns recently raised on the efficiency of competitive accretion are incorrect as they use globally averaged properties which are inappropriate for the detailed physics of a for

S. Fornasier, I. N. Belskaya, Yu. G. Shkuratov, C. Pernechele

We present the first results of an asteroid photo--polarimetry program started at Asiago--Cima Ekar Observatory. The aim of our survey is to estimate diversity in polarimetric properties of asteroids belonging to different taxonomic and dynamical classes. The data were obtained with the polarization analyser placed inside the Faint Object Spectrographic Came

Astrid M. Veronig, Manuela Temmer, Bojan Vrsnak, Julia Thalmann

We report high-cadence H-alpha observations of a distinct Moreton wave observed at Kanzelhoehe Solar Observatory associated with the 3B/X3.8 flare and CME event of 2005 January 17. The Moreton wave can be identified in about 40 H-alpha frames over a period of 7 min. The EIT wave is observed in only one frame but the derived propagation distance is close to t

E. Vanhollebeke, J. A. D. L. Blommaert, M. Schultheis, B. Aringer

Context. Galactic Centre (GC) OH/IR stars can be, based on the expansion velocities of their circumstellar shells, divided into two groups which are kinematically different and therefore are believed to have evolved from different stellar populations. Aims. To study the metallicity distribution of the OH/IR stars population in the GC on basis of a theoretica

Ilona K. Soechting, Mark E. Huber, Roger G. Clowes, Steve B. Howell

We describe a large sample of 598 galaxy clusters and rich groups discovered in the data of the Faint Sky Variability Survey. The clusters have been identified using a fully automated, semi-parametric technique based on a maximum likelihood approach applied to Voronoi tessellation, and enhanced by colour discrimination. The sample covers a wide range of rich

John R. Brucato, Giuseppa A. Baratta, Giovanni Strazzulla

Context. The chemical evolution of formamide (HCONH2), a molecule of astrobiological interest that has been tentatively identified in interstellar ices and in cometary coma, has been studied in laboratory under simulated astrophysical conditions such as ion irradiation at low temperature. Aims. To evaluate the abundances of formamide observed in space or in

Peter M. W. Kalberla, Urmas Haud

We study the properties of all major HVC complexes from a sample compiled 1991 by Wakker & van Woerden (WvW). We use the Leiden/Argentine/Bonn all sky 21-cm line survey and decompose the profiles into Gaussian components. We find a well defined multi-component structure for most of the HVC complexes. The cold HVC phase has lines with typical velocity dispers

M. Kramer, A. G. Lyne, J. T. O&#39;Brien, C. A. Jordan

PSR B1931+24 (J1933+2421) behaves as an ordinary isolated radio pulsar during active phases that are 5-10 days long. However, the radio emission switches off in less than 10 seconds and remains undetectable for the next 25-35 days, then it switches on again. This pattern repeats quasi-periodically. The origin of this behaviour is unclear. Even more remarkabl

John M. Cannon, John-David T. Smith, Fabian Walter, George J. Bendo

We present Spitzer observations of the dwarf starburst galaxy NGC 1705 obtained as part of SINGS. The galaxy morphology is very different shortward and longward of ~5 microns: short-wavelength imaging shows an underlying red stellar population, with the central super star cluster (SSC) dominating the luminosity; longer-wavelength data reveals warm dust emiss

Milena Benedettini, Jeremy A. Yates, Serena Viti, Claudio Codella

In order to investigate the origin and the structure of the low velocity, chemically rich clumps observed along the lobes of low- and intermediate-mass outflows, we construct a detailed model of the S1 clump along the CB3 outflow. We use a time-dependent chemical model coupled with a radiative transfer model to reproduce the observed line profile for a direc

Seokcheon Lee

We revise the stability of the tracking solutions and briefly review the potentials of quintessence models. We discuss the evolution of linear perturbations for $V(ϕ) = V_{0} \exp(λϕ^2/2)$ potential in which the scalar field is non-minimally coupled to cold dark matter. We consider the effects of this coupling on both cosmic microwave background temperature

U. Haud, P. M. W. Kalberla

We have analyzed the Gaussian decomposition of the Leiden/Dwingeloo Survey (LDS) of galactic neutral hydrogen for the presence of Gaussians probably not directly related to galactic HI emission. It is demonstrated that at least three classes of such components can be distinguished. The narrowest Gaussians mostly represent stronger random noise peaks in profi

M. Girardi, W. Boschin, R. Barrena

We conduct an intensive study of the rich, X-ray luminous, and hot galaxy cluster Abell 697 (at z=0.282), likely containing a diffuse radio emission, to determine its dynamical status. Our analysis is based on new spectroscopic data obtained at the TNG telescope for 93 galaxies and on new photometric data obtained at the INT telescope. We combine galaxy velo

G. Nelemans, P. G. Jonker, D. Steeghs

We present optical spectroscopy of several (candidate) ultra-compact X-ray binaries (UCXBs) obtained with the ESO VLT and Gemini-North telescopes. In only one of five observed UCXB candidates did we find evidence for H in its spectrum (4U 1556-60). For XB 1905+00 the optical counterpart is not detected. For the known UCXBs 4U 1626-67 and XB 1916-05 we find s

A. Petric, M. Lacy, L. J. Storrie-Lombardi, A. Sajina

We present a preliminary investigation of the spectral energy distributions (SEDs), and star-formation properties of a sample of Mid-IR selected Quasars. The mid-infrared SEDs of our objects are consistent with that expected from clumpy torus models. At longer wavelengths, the radio to infrared ratios of several objects are consistent with those of star-form

Y. Shirasaki, M. Tanaka, S. Kawanomoto, S. Honda

We present the design and implementation of the Japanese Virtual Observatory (JVO) system. JVO is a portal site to various kinds of astronomical resources distributed all over the world. We have developed five components for constructing the portal: (1) registry, (2) data service, (3) workflow system, (4) data analysis service (5) portal GUI. Registry servic

Roberto D. D. Costa, Walter J. Maciel

The role of planetary nebulae as probes for the galactic chemical evolution is reviewed. Their abundances throughout the Galaxy are discussed for key elements, in particular oxygen and other alpha elements. The abundance distribution derived from planetary nebulae leads to the establishment of radial abundance gradients in the galactic disk that are importan

Alexander Hubbard, Eric G. Blackman

Active Galactic Nuclei can produce extremely powerful jets. While tightly collimated, the scale of these jets and the stellar density at galactic centers implies that there will be many jet/star interactions, which can mass-load the jet through stellar winds. Previous work employed modest wind mass outflow rates, but this does not apply when mass loading is

D. F. Mota

This thesis describes a detailed investigation of the effects of matter inhomogeneities on the cosmological evolution of the fine structure constant using the Bekenstein-Sandvik-Barrow-Magueijo (BSBM) theory. We briefly review the observational and theoretical motivations to this work, together with the standard cosmological model. We start by analysing the

Michael J. Gagen, Kae Nemoto

In game theory, players have continuous expected payoff functions and can use fixed point theorems to locate equilibria. This optimization method requires that players adopt a particular type of probability measure space. Here, we introduce alternate probability measure spaces altering the dimensionality, continuity, and differentiability properties of what

Tao Hu, B. I. Shklovskii

We study the hopping conduction in a composite made of straight metallic nanowires randomly and isotropically suspended in an insulator. Uncontrolled donors and acceptors in the insulator lead to random charging of wires and hence finite bare density of states at the Fermi level. Then the Coulomb interactions between electrons of distant wires result in the

A. M. Fedotov, N. B. Narozhny

Generation of odd harmonics by a super strong focused laser beam in vacuum is considered. The process occurs due to the plural light-by-light scattering effect. In the leading order of perturbation theory, generation of $(2k+1)$th harmonic is described by a loop diagram with $(2k+2)$ external incoming, and two outgoing legs. A frequency of the beam is assume

G. Worthey, H. -c. Lee

A collection of Johnson/Cousins photometry for stars with known [Fe/H] is used to generate color-color relations that include the abundance dependence. Literature temperature and bolometric correction dependences are attached to the color relations. The main result of this work is the tabulation of seven colors and the V-band bolometric correction as a funct

Jun-Hwan Choi, Yu Lu, H. J. Mo, Martin D. Weinberg

We consider the sensitivity of the circular-orbit adiabatic contraction approximation to the baryon condensation rate and the orbital structure of dark matter halos in the $Λ$CDM paradigm. Using one-dimensional hydrodynamic simulations including the dark matter halo mass accretion history and gas cooling, we demonstrate that the adiabatic approximation is ap

M. Gmitra, J. Barnas

Spin transfer torque in spin valves usually destabilizes one of the collinear configurations (either parallel or antiparallel) and stabilizes the second one. Apart from this, balance of the spin-transfer and damping torques can lead to steady precessional modes. In this letter we show that in some asymmetric nanopillars spin current can destabilize both para