January 2007 arXiv papers — page 11

Johann Summhammer

Quantum experiments yield random data. We show that the most efficient way to store this empirical information by a finite number of bits is by means of the vector of square roots of observed relative frequencies. This vector has the unique property that its dispersion becomes invariant of the underlying probabilities, and therefore invariant of the physical

Martin Berninger, André Stefanov, Sarayut Deachapunya, Markus Arndt

We apply near-field matter-wave interferometry to determine the absolute scalar polarizability of the fullerenes C$_{60}$ and C$_{70}$. A key feature of our experiment is the combination of good transmission and high spatial resolution, gained by wide molecular beams passing through sub-micron gratings. This allows to significantly facilitate the observation

J. Y. Georges, A. Billes, S. Ferraroli, S. Fossette

Despite decades of conservation efforts on the nesting beaches, the critical status of leatherback turtles shows that their survival predominantly depends on our ability to reduce at-sea mortality. Although areas where leatherbacks meet fisheries have been identified during the long distance movements between two consecutive nesting seasons, hotspots of leth

Joanna Furno, Kerry Kuehn

The equilibrium tide-generating forces in the lunar orbital plane of a planet of radius R are calculated for the case of N moons of mass M_i orbiting the planet at instantaneous polar coordinates (D_i, α_i). For the case of a single moon, there are only two high tides. For the case of two moons, it is found that there can exist a critical lunar orbital dista

Dmitry Kazantsev

The local electromagnetic field distribution over the dielectric (SiC) surface illuminated by mid-IR light of frequency close to the lattice resonance was directly mapped with an apertureless scattering near-field optical microscope. Half of the sample surface was covered with a metal layer, in which some small $(0.2-10 μm)$ holes were formed. It was found,

D. C. Salisbury

In a paper appearing in Annalen der Physik in 1930 Leon Rosenfeld invented the first procedure for producing Hamiltonian constraints. He displayed and correctly distinguished the vanishing Hamiltonian generator of time evolution, and the vanishing generator of gauge transformations for general relativity with Dirac electron and electrodynamic field sources.

A. Bazan, M. Torres, F. R. Montero de Espinosa, R. Quintero-Torres

Conformal mapping of a slab of a two-dimensional ultrasonic crystal generate a closed geometrical arrangement of ultrasonic scatterers with appealing acoustic properties. This acoustic shell is able to confine ultrasonic modes. Some of these internal resonances can be induced from an external wave source. The mapping of a linear defect produces a wave-guide

Ryan M. Camacho, Curtis J. Broadbent, Irfan Ali-Khan, John C. Howell

Two-dimensional images carried by optical pulses (2 ns) are delayed by up to 10 ns in a 10 cm cesium vapor cell. By interfering the delayed images with a local oscillator, the transverse phase and amplitude profiles of the images are shown to be preserved. It is further shown that delayed images can be well preserved even at very low light levels, where each

A. J. Bennett, R. G. Harrison

Electricity in the atmosphere provides an ideal topic for educational outreach in environmental science. To support this objective, a simple instrument to measure real atmospheric electrical parameters has been developed and its performance evaluated. This project compliments educational activities undertaken by the Coupling of Atmospheric Layers (CAL) Europ

Yulian V. Vanne Alejandro Saenz

The quasistatic limit of the velocity-gauge strong-field approximation describing the ionization rate of atomic or molecular systems exposed to linear polarized laser fields is derived. It is shown that in the low-frequency limit the ionization rate is proportional to the laser frequency, if a Coulombic long-range interaction is present. An expression for th

Ilya Kuprov, Nicola Wagner-Rundell, P. J. Hore

The conventional spin dynamics simulations are performed in direct products of state spaces of individual spins. In a general system of n spins, the total number of elements in the state basis is >4^n. A system propagation step requires an action by an operator on the state vector and thus requires >4^2n multiplications. It is obvious that with current compu

A. Kupliauskiene

The general expression for excitation cross section of polarized atoms by polarized electrons is derived by using the methods of the theory of an atom adapted for polarization. The special cases of the general expression for the description of the angular distribution and alignment of excited atoms in the case of polarized and non-polarized atoms as well as

H. H. He, P. Bernardini, A. K. Calabrese Melcarne, S. Z. Chen

In Extensive Air Shower (EAS) experiments, the primary direction is reconstructed by the space-time pattern of secondary particles. Thus the equalization of the transit time of signals coming from different parts of the detector is crucial in order to get the best angular resolution and pointing accuracy allowed by the detector. In this paper an off-line cal

Julian J. McAuley, Luciano da Fontoura Costa, Tiberio S. Caetano

The so-called rich-club phenomenon in a complex network is characterized when nodes of higher degree (hubs) are better connected among themselves than are nodes with smaller degree. The presence of the rich-club phenomenon may be an indicator of several interesting high-level network properties, such as tolerance to hub failures. Here we investigate the exis

R. Machleidt

I review the recent progress in our understanding of nuclear forces in terms of an effective field theory (EFT) for low-energy QCD and put this progress into historical perspective. This is followed by an assessment of the current status of EFT based nuclear potentials. In concluding, I will summarize some unresolved issues.

M. Horoi, S. Stoica, B. A. Brown

The two-neutrino double beta decay matrix elements and half-lives of $^{48}$Ca, are calculated within a shell-model approach for transitions to the ground state and to the $2^+$ first excited state of $^{48}$Ti. We use the full $pf$ model space and the GXPF1A interaction, which was recently proposed to describe the spectroscopic properties of the nuclei in t

R. Witt

We present the first measurements of the transverse momentum spectra and mid-rapidity yields of the $Ξ^{0}(1530)$ multi-strange baryon resonance, from $\sqrt{\mathrm{s_{NN}}}=200$ GeV Au+Au collisions at RHIC from the STAR experiment. Ratios of the mid-rapidity yield of this long-lived ($cτ=21$ fm) resonance to its non-resonance partner (the $Ξ$ baryon) are

J. T. Mitchell

Recent surveys of multiplicity fluctuations, transverse momentum fluctuations, and two-particle azimuthal correlations are presented for several collision systems as a function of centrality and transverse momentum. Both multiplicity and transverse momentum fluctuations exhibit a power law scaling as a function of the number of participants that is independe

Levente Molnar

In this proceedings we present STAR measurements of two particle azimuthal correlations between trigger particles at mid-rapidity ($|η|<$ 1) and associated particles at forward rapidities (2.7 $<|η|<$ 3.9) in p+p, d+Au and Au+Au collisions at $\sqrt{s_{NN}} $= 200 GeV. Two particle azimuthal correlations between a mid-rapidity trigger particle and forward-ra

B. Sahlmueller

Measurements of inclusive spectra of hadrons at large transverse momentum over a broad range of energy in different collision systems have been performed with the PHENIX experiment at RHIC. The data allow to study the energy and system size dependence of the suppression observed in RAA of high-pT hadrons at sqrt(s_NN)= 200 GeV. Due to the large energy range

Manuel Calderon de la Barca Sanchez

We summarize here recent results from the STAR collaboration focusing on processes involving large momentum transfers. Measurements of angular correlations of di-hadrons are explored in both the pseudorapidity (eta) and azimuthal (phi) projections. In central Au+Au, an elongated structure is found in the eta projection which persists up to the highest measur

M. K. Suleymanov1, O. B. Abdinov, R. M. Aliyev, F. M. Aliyev

We will discuss the experimental results of the behavior of the angular distributions of slow particles emitted in hadron-nuclear and nuclear-nuclear interactions at relativistic energies.

Yoshimasa Matsuno

We show that the analytic N-soliton solution of the Camassa-Holm (CH) shallow-water model equation converges to the nonanalytic N-peakon solution of the dispersionless CH equation when the dispersion parameter tends to zero. To demonstrate this, we develop a novel limiting procedure and apply it to the parametric representation for the N-soliton solution of

Antonio Azzollini

In this paper we consider the nonlinear equation involving differential forms on a compact Riemannian manifold $δd ξ= f&#39;(<ξ,ξ>)ξ$. This equation is a generalization of the semilinear Maxwell equations recently introduced in a paper by Benci and Fortunato. We obtain a multiplicity result both in the positive mass case (i.e. $f&#39;(t)\geqε>0$ uniformly) a

Vladimir Tolstykh

Let $A$ be an infinitely generated free abelian group. We prove that the automorphism group $\aut A$ first-order interprets the full second-order theory of the set $|A|$ with no structure. In particular, this implies that the automorphism groups of two infinitely generated free abelian groups $A_1,A_2$ are elementarily equivalent if and only if the sets $|A_

Vladimir Tolstykh, Valery Bardakov

We prove that the elementary theory of Thompson&#39;s group $F$ is hereditarily undecidable.

Francois Metayer

We define a notion of cofibration among n-categories and show that the cofibrant objects are exactly the free ones, that is those generated by polygraphs.

Jean-Marc Bardet, Paul Doukhan, José Rafael León

We prove uniform convergence results for the integrated periodogram of a weakly dependent time series, namely a law of large numbers and a central limit theorem. These results are applied to Whittle&#39;s parametric estimation. Under general weak-dependence assumptions we derive uniform limit theorems and asymptotic normality of Whittle&#39;s estimate for a

Partha Sarathi Chakraborty, Arupkumar Pal

The torus group $(S^1)^{\ell+1}$ has a canonical action on the odd dimensional sphere $S_q^{2\ell+1}$. We take the natural Hilbert space representation where this action is implemented and characterize all odd spectral triples acting on that space and equivariant with respect to that action. This characterization gives a construction of an optimum family of

Y. Kondratiev, E. Lytvynov, M. Röckner

We study the problem of identification of a proper state-space for the stochastic dynamics of free particles in continuum, with their possible birth and death. In this dynamics, the motion of each separate particle is described by a fixed Markov process $M$ on a Riemannian manifold $X$. The main problem arising here is a possible collapse of the system, in t

Basudeb Datta

In this survey article, we are interested on minimal triangulations of closed pl manifolds. We present a brief survey on the works done in last 25 years on the following: (i) Finding the minimal number of vertices required to triangulate a given pl manifold. (ii) Given positive integers $n$ and $d$, construction of $n$-vertex triangulations of different $d$-

Andrei Asinowski, Toufik Mansour

We introduce a notion of Dyck paths with coloured ascents. For several ways of colouring, we establish bijections between sets of such paths and other combinatorial structures, such as non-crossing trees, dissections of a convex polygon, etc. In some cases enumeration gives new expression for sequences enumerating these structures.

Mitsuru Sugimoto, Naohito Tomita

We prove that pseudo-differential operators with symbols in the class $S_{1,δ}^0$ ($0<δ<1$) are not always bounded on the modulation space $M^{p,q}$ ($q\neq2$).

Oliver Goertsches, Gudlaugur Thorbergsson

We investigate the submanifold geometry of the orbits of Hermann actions on Riemannian symmetric spaces. After proving that the curvature and shape operators of these orbits commute, we calculate the eigenvalues of the shape operators in terms of the restricted roots. As applications, we get a formula for the volumes of the orbits and a new proof of a Weyl-t

Nguyen Tu Cuong, Hoang Le Truong

Let $M$ be a finitely generated module of dimension $d$ over a Noetherian local ring $(R,\m)$ and $\q $ the parameter ideal generated by a system of parameters $\x = (x_1,..., x_d)$ of $M$. For each positive integer $n$, set $$Λ_{d,n}=\{α=(α_1,...,α_d)\in\Bbb{Z}^d|α_i\geqslant 1, \forall 1\leqslant i\leqslant d \text{and} \sum\limits_{i=1}^dα_i=d+n-1\}$$ and

Nguyen Tu Cuong, Doan Trung Cuong

A finitely generated module $M$ over a local ring is called a sequentially generalized Cohen-Macaulay module if there is a filtration of submodules of $M$: $M_0\subset M_1\subset ... \subset M_t=M$ such that $\dim M_0<\dim M_1< >... <\dim M_t$ and each $M_i/M_{i-1}$ is generalized Cohen-Macaulay. The aim of this paper is to study the structure of this class

Dominic Schuhmacher

In [Schuhmacher, Electron. J. Probab. 10 (2005), 165--201] estimates of the Barbour-Brown distance d_2 between the distribution of a thinned point process and the distribution of a Poisson process were derived by combining discretization with a result based on Stein&#39;s method. In the present article we concentrate on point processes that have a density wi

Haseo Ki

We study the horizontal distribution of zeros of $ζ&#39;(s)$ which are denoted as $ρ&#39;=β&#39;+iγ&#39;$. We assume the Riemann hypothesis which implies $β&#39;\geqslant1/2$ for any non-real zero $ρ&#39;$, equality being possible only at a multiple zero of $ζ(s)$. In this paper we prove that $\liminf(β&#39;-1/2)\logγ&#39;\not=0$ if and only if for any $c>0$

Long Wang, Feng Xiao

In this paper, finite-time state consensus problems for continuous-time multi-agent systems are discussed, and two distributive protocols, which ensure that the states of agents reach an agreement in a finite time, are presented. By employing the method of finite-time Lyapunov functions, we derive conditions that guarantee the two protocols to solve the fini

Yan-Quan Feng, Klavdija Kutnar, Aleksander Malnic, Dragan Marusic

A regular covering projection $\p\colon \tX \to X$ of connected graphs is $G$-admissible if $G$ lifts along $\p$. Denote by $\tG$ the lifted group, and let $\CT(\p)$ be the group of covering transformations. The projection is called $G$-split whenever the extension $\CT(\p) \to \tG \to G$ splits. In this paper, split 2-covers are considered. Supposing that $

Leonardo Modesto

In this paper we summarize &#34;loop quantum gravity&#34; (LQG) and we show how ideas developed in LQG can solve the black hole singularity problem when applied to a minisuperspace model.

V. Dolotin, A. Morozov

Direct look at the celebrated &#34;chaotic&#34; Mandelbrot Set in Fig..\ref{Mand2} immediately reveals that it is a collection of almost ideal circles and cardioids, unified in a specific {\it forest} structure. In /hep-th/9501235 a systematic algebro-geometric approach was developed to the study of generic Mandelbrot sets, but emergency of nearly ideal circ

J. Pumplin, H. L. Lai, W. K. Tung

We investigate the charm sector of the nucleon structure phenomenologically, using the most up-to-date global QCD analysis. Going beyond the common assumption of purely radiatively generated charm, we explore possible degrees of freedom in the parton parameter space associated with nonperturbative (intrinsic) charm in the nucleon. Specifically, we explore th

Nick Evans

A holographic description of chiral symmetry breaking in the pattern of QCD is reviewed. D7 brane probes are used to include quark fields in a simple non-supersymmetric deformation of the AdS/CFT Correspondence. The axial symmetry breaking is realized geometrically and the quark condensate and meson masses are computable. Surprisingly, treating the model as

Robert Fleischer

We give an overview of various determinations of $γ/ϕ_3$ with the help of $B_s$ decays into charmed final states, distinguishing between transitions with tree and penguin contributions and pure tree decays. In the corresponding strategies, the $U$-spin flavour symmetry of strong interactions provides a very useful tool, and offers interesting &#34;by-producs

Jim Gray

This provides a retrospective of the paper &#34;A Measure of Transaction Processing&#34; published in 1985. It shows that transaction processing peak performance and price-peformance have improved about 100,000x respectively and that sort/sequential performance has approximately doubled each year (so a million fold improvement) even though processor performa

Jim Gray, Charles Levine

A $2k computer can execute about 8k transactions per second. This is 80x more than one of the largest US bank&#39;s 1970&#39;s traffic - it approximates the total US 1970&#39;s financial transaction volume. Very modest modern computers can easily solve yesterday&#39;s problems.

Gerd Heber, Jim Gray

This is Part II of a three article series on using databases for Finite Element Analysis (FEA). It discusses (1) db design, (2) data loading, (3) typical use cases during grid building, (4) typical use cases during simulation (get and put), (5) typical use cases during analysis (also done in Part III) and some performance measures of these cases. It argues t

Gerd Heber, Jim Gray

In this paper, we show how to use a Relational Database Management System in support of Finite Element Analysis. We believe it is a new way of thinking about data management in well-understood applications to prepare them for two major challenges, - size and integration (globalization). Neither extreme size nor integration (with other applications over the W

Jim Gray

Message-oriented-middleware (MOM) has become an small industry. MOM offers queued transaction processing as an advance over pure client-server transaction processing. This note makes four points: Queued transaction processing is less general than direct transaction processing. Queued systems are built on top of direct systems. You cannot build a direct syste

Hal Berenson, Phil Bernstein, Jim Gray, Jim Melton

ANSI SQL-92 defines Isolation Levels in terms of phenomena: Dirty Reads, Non-Repeatable Reads, and Phantoms. This paper shows that these phenomena and the ANSI SQL definitions fail to characterize several popular isolation levels, including the standard locking implementations of the levels. Investigating the ambiguities of the phenomena leads to clearer def

Jim Gray

Soon most information will be available at your fingertips, anytime, anywhere. Rapid advances in storage, communications, and processing allow us move all information into Cyberspace. Software to define, search, and visualize online information is also a key to creating and accessing online information. This article traces the evolution of data management sy

Jim Gray, Surajit Chaudhuri, Adam Bosworth, Andrew Layman

Data analysis applications typically aggregate data across many dimensions looking for anomalies or unusual patterns. The SQL aggregate functions and the GROUP BY operator produce zero-dimensional or one-dimensional aggregates. Applications need the N-dimensional generalization of these operators. This paper defines that operator, called the data cube or sim

Michal Forišek, Branislav Katreniak, Jana Katreniaková, Rastislav Královič

The paper investigates a version of the resource allocation problem arising in the wireless networking, namely in the OVSF code reallocation process. In this setting a complete binary tree of a given height $n$ is considered, together with a sequence of requests which have to be served in an online manner. The requests are of two types: an insertion request

Hajar Mahdavi-Doost, Masoud Ebrahimi, Amir K. Khandani

In this paper, an $n$-user Gaussian interference channel, where the power of the transmitters are subject to some upper-bounds is studied. We obtain a closed-form expression for the rate region of such a channel based on the Perron-Frobenius theorem. While the boundary of the rate region for the case of unconstrained power is a well-established result, this

Howard Cheng, Guillaume Hanrot, Emmanuel Thomé, Eugene Zima

The currently best known algorithms for the numerical evaluation of hypergeometric constants such as $ζ(3)$ to $d$ decimal digits have time complexity $O(M(d) \log^2 d)$ and space complexity of $O(d \log d)$ or $O(d)$. Following work from Cheng, Gergel, Kim and Zima, we present a new algorithm with the same asymptotic complexity, but more efficient in practi

Cenke Xu, Joel E. Moore

The phase diagram of the XXZ spin-1 quantum magnet on the kagome lattice is studied for all cases where the $J_z$ coupling is antiferromagnetic. In the zero magnetic field case, the six previously introduced phases, found using various methods, are: the nondegenerate gapped photon phase which breaks no space symmetry or spin symmetry; the six-fold degenerate

R. Raimondi, C. Gorini, M. Dzierzawa, P. Schwab

The quasiclassical Green function formalism is used to describe charge and spin dynamics in the presence of spin-orbit coupling. We review the results obtained for the spin Hall effect on restricted geometries. The role of boundaries is discussed in the framework of spin diffusion equations.

Hiroyuki Yamase, Andrey A. Katanin

The most salient features observed around a metamagnetic transition in Sr3Ru2O7 are well captured in a simple model for spontaneous Fermi surface symmetry breaking under a magnetic field, without invoking a putative quantum critical point. The Fermi surface symmetry breaking happens in both a majority and a minority spin band but with a different magnitude o

Pedro Castro Menezes, Alba Theumann

We show that the effective action of the quantum spherical spin glass is invariant under a generalized form of the Becchi-Rouet-Stora-Tyutin(BRST) supersymmetry. The Ward identities associated to this invariance indicate that the spin glass order parameter must vanish, and as a result the annealed average is exact in this model. We present new results for fo

Hiroyuki Yamase, Walter Metzner

A pronounced xy-anisotropy was observed in recent neutron scattering experiments for magnetic excitations in untwinned YBa_{2}Cu_{3}O_{6+y} (YBCO). The small anisotropy of the bare band structure due to the orthorhombic crystal symmetry seems to be enhanced by correlation effects. A natural possibility is that the system is close to a Pomeranchuk instability

V. Bellani, M. Amado, E. Diez, C. Koerdt

We report the experimental study of resonant Rayleigh scattering in GaAs-AlGaAs superlattices with ordered and intentionally disordered potential profiles (correlated and uncorrelated) in the growth direction z. We show that the intentional disorder along z modify markedly the energy dispersion of the dephasing rates of the excitons. The application of an ex

T. Yang, A. Hirohata, M. Hara, T. Kimura

We fabricated a current-perpendicular-to-plane pseudo-spin-valve nanopillar comprising a thick and a thin Co rings with deep submicron lateral sizes. The dc current can effectively induce the flux-closure vortex states in the rings with desired chiralities. Abrupt transitions between the vortex states are also realized by the dc current and detected with the

B. D. Gerardot, S. Seidl, P. A. Dalgarno, M. Kroner

We perform transmission spectroscopy on single quantum dots and examine the effects of a resident carriers spin, the incident laser spot size, polarization, and power on the experimental contrast. We demonstrate a factor of 4 improvement in the maximum contrast by using a solid immersion lens to decrease the spot area. This increase yields a maximum signal t

A. Yu. Kuntsevich, N. N. Klimov, S. A. Tarasenko, N. S. Averkiev

We have measured the weak localization magnetoresistance in (001)-oriented Si MOS structures with a wide range of mobilities. For the quantitative analysis of the data, we have extended the theory of weak-localization corrections in the ballistic regime to the system with two equivalent valleys in electron spectrum. This theory describes the observed magneto

Chenglong Jia, Shigeki Onoda, Naoto Nagaosa, Jung Hoon Han

A systematic microscopic theory of magnetically induced ferroelectricity and lattice modulation is presented for all electron configurations of Mott-insulating transition-metal oxides. Various mechanisms of polarization are identified in terms of a strong-coupling perturbation theory. Especially, the spin-orbit interaction acting on the ligand p orbitals is

Kouta Katayama, Shinji Kawasaki, Masahide Nishiyama, Hitoshi Sugawara

We report $^{123}$Sb nuclear quadrupole resonance (NQR) measurements of the filled skutterudite heavy-fermion superconductor PrOs$_4$Sb$_{12}$ under high pressures of 1.91 and 2.34 GPa. The temperature dependence of NQR frequency and the spin-lattice relaxation rate $1/T_1$ indicate that the crystal-electric-field splitting $Δ_{\rm CEF}$ between the ground s

P. Kleinert, V. V. Bryksin

Based on a rigorous quantum-kinetic approach, spin-charge coupled drift-diffusion equations are derived for a strongly confined two-dimensional hole gas. An electric field leads to a coupling between the spin and charge degrees of freedom. For weak spin-orbit interaction, this coupling gives rise to the intrinsic spin-Hall effect. There exists a threshold va

I. Galanakis, K. Ozdogan, E. Sasioglu, B. Aktas

Half-metallic antiferromagnets are the ideal materials for spintronic applications since their zero magnetization leads to lower stray fields and thus tiny energy losses. Starting from the Mn$_2$VAl and Mn$_2$VSi alloys we substitute Co or Fe for Mn and we show by means of first-principle electronic structure calculations that the resulting compounds are fer

K. Kaneko, N. Metoki, R. Shiina, T. D. Matsuda

Neutron scattering experiments have revealed a field-induced antiferroquadrupolar order parameter in the Pr-based heavy-fermion superconductor PrOs$_4$Sb$_{12}$. We observed the field-induced antiferromagnetic dipole moment with the propagation vector {\textit{\textbf{q}}} = (1 0 0) for the applied field direction both {\textit{\textbf{H}}}${\parallel}$[1 1

Huan-Qiang Zhou, John Paul Barjaktarevic

It is shown that the fidelity, a basic notion of quantum information science, may be used to characterize quantum phase transitions, regardless of what type of internal order is present in quantum many-body states. If the fidelity of two given states vanishes, then there are two cases: (1) they are in the same phase if the distinguishability results from irr

Gregor Veble, Rudolf Podgornik

We develop a boundary element method to calculate Van der Waals interactions for systems composed of domains of spatially constant dielectric response. We achieve this by rewriting the interaction energy expression exclusively in terms of surface integrals of surface operators. We validate this approach in the Lifshitz case and give numerical results for the

D. Semionov, V. Vansevicius

We present a program suite for the radiative transfer problem solution in axi-symmetrical dusty galaxy disks, intended primarily for spectrophotometric analysis of stellar populations by means of integrated and differential photometry. The solution is obtained using a 2D ray-tracing algorithm at a discrete wavelength set, emphasizing careful treatment of the

D. Semionov, K. Kodaira, R. Stonkute, V. Vansevicius

We study the effects of dusty spiral arms on the photometric properties of disk galaxies using a series of 2D radiative transfer models, approximating the arms with axially symmetrical rings. We find that dusty arms, as well as dusty disks, have a significant influence on the aperture photometry and surface brightness profiles altering colors of model galaxi

E. Terlevich, R. Terlevich, V. Luridiana

The presently accepted "Theory of the Universe" was pioneered 60 years ago by Gamow, Alpher and Herman. As a consequence of the, later dubbed, Hot Big-Bang, matter was neutrons, and after some decay protons, and a history of successive captures built up the elements. It wasn't until some 15 years later (with the discovery of the Cosmic Microwave Background r

I. F. Mirabel

Microquasars provide new insights into: 1) the physics of relativistic jets from black holes, 2) the connection between accretion and ejection, and 3) the physical mechanisms in the formation of stellar-mass black holes. Furthermore, the studies of microquasars in our Galaxy can provide in the future new insights on: 1) a large fraction of the ultraluminous

K. Yakut, C. Aerts, Th. Morel

Our goal was to improve the fundamental parameters of the massive close double-lined eclipsing B2.5V+B2.5V binary CV Velorum.We gathered new high-resolution echelle spectroscopy on 13 almost consecutive nights covering essentially two orbits. We computed a simultaneous solution to all the available high-quality radial-velocity and light data with the latest

Zoltan Balog, James Muzerolle, G. H. Rieke, Kate Y. L. Su

We present the results from a survey of NGC 2244 from 3.6 to 24 micron with the Spitzer Space Telescope. The 24micron-8micron-3.6micron color composite image of the region shows that the central cavity surrounding the multiple O and B stars of NGC2244 contains a large amount of cool dust visible only at 24micron. Our survey gives a detailed look at disk surv

Jorick S. Vink

For the occasion of the official retirement of Henny Lamers, a meeting was held to celebrate Henny's contribution to mass loss from stars and stellar clusters. Stellar mass loss is crucial for understanding the life and death of massive stars, as well as their environments. Henny has made important contributions to many aspects of our understanding of hot-st

J. Sollerman, J. P. U. Fynbo, J. Gorosabel, J. P. Halpern

We present comprehensive photometric R-band observations of the fading optical afterglow of the X-Ray Flash XRF050824, from 11 minutes to 104 days after the burst. The R-band lightcurve of the afterglow resembles the lightcurves of long duration Gamma-Ray Bursts (GRBs), i.e., a power-law albeit with a rather shallow slope of alpha=0.6. Our late R-band images

K. G. Stassun, M. van den Berg, E. Feigelson

We present a statistical analysis of simultaneous optical and X-ray light curves, spanning 600 ks, for 814 pre-main-sequence (PMS) stars in the Orion Nebula Cluster. The aim of this study is to establish the relationship, if any, between the sites of optical and X-ray variability, and thereby to elucidate the origins of X-ray production in PMS stars. In a pr

Prashanth Jaikumar

Under extreme conditions of temperature and/or density, quarks and gluons are expected to undergo a deconfinement phase transition. While this is an ephemeral phenomenon at the ultra-relativistic heavy-ion collider (BNL-RHIC), quark matter may exist naturally in the dense interior of neutron stars. Herein, we present an appraisal of the possible phase struct

Brian Punsly

In this Letter, the broad emission line (BEL) profiles of superluminal quasars with apparent jet velocities, $β_{a}>10$, (ultraluminal QSOs, or ULQSOs hereafter) are studied as a diagnostic of the velocity field of the BEL emitting gas in quasars. The ULQSOs are useful because they satisfy a very strict kinematical constraint, their parsec scale jets must be

E. Noordermeer, J. M. van der Hulst, R. Sancisi, R. S. Swaters

We present rotation curves for 19, mostly luminous, early-type disk galaxies. Rotation velocities are measured from a combination of HI velocity fields and long-slit optical emission line spectra along the major axis. We find that the rotation curves generally rise rapidly in the central regions and often reach rotation velocities of 200 - 300 km/s within a

E. Noordermeer, J. M. van der Hulst

We present deep B- and R-band surface photometry for a sample of 21 galaxies with morphological types between S0 and Sab. We present radial profiles of surface brightness, colour, ellipticity, position angle and deviations of axisymmetry for all galaxies, as well as isophotal and effective radii and total magnitudes. We have decomposed the images into contri

E. J. Bernard, M. Monelli, C. Gallart, A. Aparicio

We present preliminary results concerning the search for short-period variable stars in Tucana and LGS3 based on very deep HST/ACS imaging. In the fraction of the observed field we studied in each galaxy, a total of 133 and 30 variables were found, respectively. For Tucana, we identified 76 of them as RR Lyrae (RRL) stars pulsating in the fundamental mode (R

Simon P. Driver, Paul D. Allen, Jochen Liske, Alister W. Graham

We derive the luminosity functions of elliptical galaxies, galaxy bulges, galaxy pseudo-bulges and galaxy discs from our structural catalogue of 10,095 galaxies. In addition we compute their associated luminosity and stellar mass densities. We show that spheroidal systems (elliptical galaxies and the bulges of disc galaxies) exhibit a strong color bimodality

A. T. Valcheva, V. D. Ivanov, E. P. Ovcharov, P. L. Nedialkov

We identify the rich Carbon star population of the Magellanic-type dwarf irregular galaxy WLM (Wolf-Lundmark-Melotte) and study its photometric properties from deep near-IR observations. The galaxy exhibits also a clear presence of Oxygen rich population. We derive a Carbon to M-star ratio of C/M=0.56(+/-0.12), relatively high in comparison with many galaxie

Carme Gallart

In this contribution I present the main research activities of the IAC ``Stellar Populations in Galaxies&#39;&#39; research Group, with emphasis on the subtopics directly related with the study of the evolution of nearby galaxies. In particular, I discuss preliminary results of ongoing research on the Magellanic Clouds using deep ground-based observations, a

Aprajita Verma, Matthew D. Lehnert, Natascha M. Foerster Schreiber, Malcolm N. Bremer

We determine the ensemble properties of z~5 Lyman break galaxies (LBGs) selected as V-band dropouts to i(AB)<26.3 in the Chandra Deep Field South using their rest-frame UV-to-visible SEDs. By matching the selection and performing the same analysis that has been used for z~3 samples, we show clear differences in the properties of two samples of LBGs which are

Laura S. Douglas, Malcolm N. Bremer, Elizabeth R. Stanway, Matthew D. Lehnert

As part of a large spectroscopic survey of z>5 Lyman break galaxies (LBGs), we have identified a single source which is clearly hosting an AGN. Out of a sample of more than fifty spectroscopically-confirmed R-band dropout galaxies at z~5 and above, only J104048.6-115550.2 at z=5.44 shows evidence for a high ionisation-potential emission-line indicating the p

M. Puech, F. Hammer, M. D. Lehnert, H. Flores

[Abridged] One of the most outstanding problems related to numerical models of galaxy formation is the so-called ``angular momentum catastrophe&#39;&#39;. We study the evolution of the angular momentum from z~0.6 to z=0 to further our understanding of the mechanisms responsible for the large angular momenta of disk galaxies observed today. This study is base

Frederic Malacrino, Jean-Luc Atteia, Michel Boer, Alain Klotz

We analyze images of the CFHTLS Very Wide Survey to search for visible orphan afterglows from gamma-ray bursts (GRBs). We have searched 490 square degrees down to magnitude r&#39;=22.5 for visible transients similar to GRB afterglows. We translate our observations into constraints on the number of GRB visible afterglows in the sky, by measuring the detection

Marek Biesiada

There are several different theoretical ideas invoked to explain the dark energy with relatively little guidance of which one of them might be right. Therefore the emphasis of ongoing and forthcoming research in this field shifts from estimating specific parameters of cosmological model to the model selection. In this paper we apply information-theoretic mod

Z. E. Musielak, S. Routh, R. Hammer

Propagation of torsional Alfvén waves along magnetic flux tubes has been extensively studied for many years but no conclusive results regarding the existence of a cutoff frequency for these waves have been obtained. The main purpose of this paper is to derive new wave equations that describe the propagation of linear torsional Alfvén waves along thin and iso

Jeremy Shears, Gary Poyner

Nova Lyrae was discovered at the Harvard College Observatory on 1919 December 6 at magnitude 6.5. We present a lightcurve for this nova based on published and archival observations. This was a classical fast nova, probably of type B. Decline times were t2 = 31 or 47d, depending on the method used, and t3 = 97d. The amplitude was at least 9.5 magnitudes. Base

S. Dreizler, S. Schuh, D. Homeier

The Optical Gravitational Lensing Experiment project has recently provided the OGLE III list of low-luminosity object transits from campaigns #3 and #4, reporting 40 new objects exhibiting the low-amplitude photometric eclipses expected for exoplanets. Compared to previous OGLE targets, these OGLE III candidates have been more restrictively selected and may

Michal Svanda, Junwei Zhao, Alexander G. Kosovichev

We present a direct comparison between two different techniques time-distance helioseismology and a local correlation tracking method for measuring mass flows in the solar photosphere and in a near-surface layer: We applied both methods to the same dataset (MDI high-cadence Dopplergrams covering almost the entire Carrington rotation 1974) and compared the re

T. Oosterloo, R. Morganti, E. M. Sadler, J. M. van der Hulst

We discuss the morphology and kinematics of the HI of a sample of 30 southern gas-rich early-type galaxies selected from the HI Parkes All-Sky Survey (HIPASS). This is the largest collection of high-resolution HI data of a homogeneously selected sample. Given the sensitivity of HIPASS, these galaxies represent the most HI-rich early-type galaxies. In two-thi

K. Bekki, M. -R. L. Cioni

Recent morphological studies of galaxies by the {\it Hubble Space Telescope (HST)} have revealed that actively star-forming galaxies at intermediate and high redshifts ($z=0.5-2.0$) have very clumpy and irregular distributions of stars. It is however unclear whether and how these clumpy galaxies evolve into the present spiral and elliptical galaxies with reg