September 2001 arXiv papers — page 3

Carlo Callegari, Kevin K. Lehmann, Roman Schmied, Giacinto Scoles

In this article, recent developments in HElium NanoDroplet Isolation (HENDI) spectroscopy are reviewed, with an emphasis on the infrared region of the spectrum. Topics discussed include experimental details, comparison of radiation sources, symmetry issues of the helium solvation structure, sources of line broadening, changes in spectroscopic constants upon

S. Kraft, M. Mudrich, K. Singer, R. Grimm

We present first indications of sympathetic cooling between two neutral, optically trapped atomic species. Lithium and cesium atoms are simultaneously stored in an optical dipole trap formed by the focus of a CO$_2$ laser, and allowed to interact for a given period of time. The temperature of the lithium gas is found to decrease when in thermal contact with

J. W. Clark, E. Mavrommatis, S. Athanassopoulos, A. Dakos

Statistical modeling of data sets by neural-network techniques is offered as an alternative to traditional semiempirical approaches to global modeling of nuclear properties. New results are presented to support the position that such novel techniques can rival conventional theory in predictive power, if not in economy of description. Examples include the sta

L. A. Blanco, R. Bonnaz, B. Silvestre-Brac, F. Fernandez

The classical van Royen-Weisskopf formula for the decay width of a meson into a lepton-antilepton pair is modified in order to include non-zero quark momentum contributions within the meson as well as relativistic effects. Besides, a phenomenological electromagnetic density for quarks is introduced. The meson wave functions are obtained from two different mo

Pierre Desesquelles

We present a new method for the calculation of fragment size correlations in a discrete finite system in which correlations explicitly due to the finite extent of the system are suppressed. To this end, we introduce a combinatorial model, which describes the fragmentation of a finite system as a sequence of independent random emissions of fragments. The sequ

Alastair Craw

By associating a `motivic integral' to every complex projective variety X with at worst canonical, Gorenstein singularities, Kontsevich proved that, when there exists a crepant resolution of singularities Y of X, the Hodge numbers of Y do not depend upon the choice of the resolution. In this article we provide an elementary introduction to the theory of

Tom Graber, Joe Harris, Jason Starr

We prove that a one-parameter family of rationally connected varieties (over an algebraically closed field of characteristic 0) always has a section.

Eric S. Egge

We give enumerations of various families of restricted permutations involving the Fibonacci numbers or k-generalized Fibonacci numbers.

Christian Pauly

The moduli space M_0 of semi-stable rank 2 vector bundles with fixed trivial determinant over a non-hyperelliptic curve C of genus 3 is isomorphic to a quartic hypersurface in P^7 (Coble's quartic). We show that M_0 is self-dual and that its polar map associates to a stable bundle E \in M_0 a bundle F which is characterized by dim H^0(C, E \otimes F) = 4

Siegfried Echterhoff, John Quigg

Using the strong relation between coactions of a discrete group G on C*-algebras and Fell bundles over G, we prove a new version of Mansfield's imprimitivity theorem for coactions of discrete groups. Our imprimitivity theorem works for the universally defined full crossed products and arbitrary subgroups of G, as opposed to the usual theory which uses th

E. Shargorodsky, A. V. Sobolev

We study spectral properties of second order elliptic operators with periodic coefficients in dimension two. These operators act in periodic simply-connected waveguides, with either Dirichlet, or Neumann, or the third boundary condition. The main result is the absolute continuity of the spectra of such operators. The corner stone of the proof is an isotherma

Olalla A. Castro-Alvaredo

The bootstrap program for 1+1-dimensional integrable Quantum Field Theories (QFT's) is developed to a large extent for the Homogeneous sine-Gordon (HSG) models. This program can be divided into various steps, which include the computation of the exact S-matrix, Form Factors of local operators and correlation functions, as well as the identification of th

M. Chaichian, A. Kobakhidze, M. Tsulaia

We consider the problem of supersymmetry breaking in 5 dimensional N=1 supersymmetric models with $S^1/Z_2$ compactification.

Thomas Branson, A. Rod Gover

We derive a tensorial formula for a fourth-order conformally invariant differential operator on conformal 4-manifolds. This operator is applied to algebraic Weyl tensor densities of a certain conformal weight, and takes its values in algebraic Weyl tensor densities of another weight. For oriented manifolds, this operator reverses duality: For example in the

D. Bernard, Th. Cousin, V. A. Karmanov, J. -F. Mathiot

Within the covariant formulation of Light-Front Dynamics, in a scalar model with the interaction Hamiltonian $H=-gψ^{2}(x)ϕ(x)$, we calculate nonperturbatively the renormalized state vector of a scalar "nucleon" in a truncated Fock space containing the $N$, $Nπ$ and $Nππ$ sectors. The model gives a simple example of non-perturbative renormalization w

Ph. Brax, J. Martin, A. Riazuelo

A short review of some of the aspects of quintessence model building is presented. We emphasize the role of tracking models and their possible supersymmetric origin.

E. K. Loginov

In this paper the linear representations of analytic Moufang loops are investigated. We prove that every representation of semisimple analytic Moufang loop is completely reducible and find all nonassociative irreducible representations. We show that such representations are closely associated with the (anti-)self-dual Yang-Mills equations in ${\bf R}^8$

Savely G. Karshenboim, Vladimir G. Ivanov

We consider hyperfine splitting of 1s and, in part, of 2s levels in light hydrogen-like atoms: hydrogen, deuterium, tritium, helium-3 ion, muonium and positronium. We discuss present status of precision theory and experiment for the hfs intervals. We pay a special attention to a specific difference, D_{21} = 8 E_{hfs}(2s) - E_{hfs}(1s), which is known experi

Piotr H. Chankowski, Adam Falkowski, Stefan Pokorski

We examine unification of gauge couplings in four dimensional renormalizable gauge theories inspired by the latticized (deconstructed) SM or MSSM in five dimensions. The models are based on replicated gauge groups, spontaneously broken to the diagonal subgroup. The analysis is performed at one-loop level, with the contribution from the heavy vector bosons in

Ernest Ma

The physics responsible for neutrino mass may reside at or below the TeV energy scale. The neutrino mass matrix in the $(ν_e, ν_μ, ν_τ)$ basis may then be deduced from future high-energy accelerator experiments. The newly observed excess in the muon anomalous magnetic moment may also be related.

A. Rebhan

Starting from a nonperturbative expression for entropy and density obtained from $Φ$-derivable two-loop approximations to the thermodynamic potential, a quasiparticle model for the thermodynamics of QCD can be developed which incorporates the physics of hard thermal loops and leads to a reorganization of the otherwise ill-behaved thermal perturbation theory

E. Christova, E. Leader, S. Kretzer

We discuss how to extract the polarized parton densities and fragmentation functions in a model independent way from SIDIS, and present results for D_{u,d,s}^{π^+}.

Chun Liu

If the tau neutrino is as heavy as 10 MeV which may have certain astrophysical implications, the neutrino mass pattern is studied so as to accommodate the new oscillation observations. It predicts that the electron neutrino has Marjorana mass around 0.05 eV. A supersymmetric model is described to realize the above scenario.

S. Descotes, C. T. Sachrajda

In order to obtain information about the Standard Model from exclusive hadronic two-body B-decays, we have to quantify non-perturbative QCD effects. Approaches based on the factorization of mass singularities into hadronic distribution amplitudes and form factors provide a rigorous theoretical framework for the evaluation of these effects in the heavy quark

Hai-Yang Cheng

We have systematically investigated the semi-inclusive B decays $B\to MX$, which are manifestations of the quark decay $b \to Mq$, within a framework inspired by QCD-improved factorization. These decays are theoretically clean and have distinctive experimental signatures. We focus on a class of these that do not require any form factor information and theref

A. I. Milstein, O. P. Sushkov

Parity nonconservation due to the nuclear weak charge is considered. We demonstrate that the radiative corrections to this effect due to the vacuum fluctuations of the characteristic size larger than the nuclear radius $r_0$ and smaller than the electron Compton wave-length $λ_C$ are enhanced because of the strong electric field of the nucleus. The parameter

Kurt Langfeld

High density YM-theory is addressed by means of an effective theory where a Higgs type field corresponds to the diquark order parameter. The effective Higgs theory mimics the Cooper instability at the Fermi surface. After Landau gauge fixing, the theory possesses a global color degree of freedom. Color superconductivity corresponds to a spontaneous breakdown

M. Faber, J. Greensite, S. Olejnik

We introduce a variation of direct maximal center gauge fixing: the "direct Laplacian" center gauge. The new procedure consists of first fixing to the Laplacian adjoint Landau gauge, followed by overrelaxation to the nearby Gribov copy of the direct maximal center gauge. Certain shortcomings of maximal center gauge, associated with Gribov copies, are

P. Bialas, J. Wosiek

Lattice discretization of the supersymmetric Yang-Mills quantum mechanics is dis cussed. First results of the quenched Monte Carlo simulations, for D=4 and with higher g auge groups (3 <= N <= 8), are presented. We confirm an earlier (N=2) evidence tha t the system reveals different behaviours at low and high temperatures separated by a narrow transiti on re

R. G. Daghigh, J. I. Kapusta

The relativistic viscous fluid equations describing the outflow of high temperature matter created via Hawking radiation from microscopic black holes are solved numerically for a realistic equation of state. We focus on black holes with initial temperatures greater than 100 GeV and lifetimes less than 6 days. The spectra of direct photons and photons from $π

C. S. Unnikrishnan, G. T. Gillies, R. C. Ritter

We discuss the evolution of the Universe from what might be called its quantum origin. We apply the uncertainty principle to the origin of the Universe with characteristic time scale equal to the Planck time to obtain its initial temperature and density. We establish that the subsequent evolution obeying the Einstein equation gives the present temperature of

Anand S. Sengupta, Sanjeev V. Dhurandhar, Albert Lazzarini, Tom Prince

Pattern matching techniques like matched filtering will be used for online extraction of gravitational wave signals buried inside detector noise. This involves cross correlating the detector output with hundreds of thousands of templates spanning a multi-dimensional parameter space, which is very expensive computationally. A faster implementation algorithm w

Hernan Galperin, Francois Bar

In this paper we analyze the development of interactive TV in the U.S. and Western Europe. We argue that despite the nascent character of the market there are important regulatory issues at stake, as exemplified by the AOL/TW merger and the British Interactive Broadcasting case. Absent rules that provide for non-discriminatory access to network components (i

D. E. MacLaughlin, O. O. Bernal, J. E. Sonier, R. H. Heffner

Magnetic susceptibility and muon spin rotation (\muSR) experiments have been carried out to study the effect of structural disorder on the non-Fermi-liquid (NFL) behavior of the heavy-fermion alloy Ce(Ru_{0.5}Rh_{0.5})_2Si_2. Analysis of the bulk susceptibility in the framework of disorder-driven Griffiths-phase and Kondo-disorder models for NFL behavior yie

Colette Boskovic, Maren Pink, John C. Huffman, David N. Hendrickson

The Mn12Ac single-molecule magnet has been converted for the first time into a form that contains non-carboxylate ligands. Reaction of Mn12Ac with diphenylphosphinic acid converts it into the title compound in which eight of the acetate (Ac) groups have been replaced with Ph2PO2 (P) groups. The Mn12AcP product retains the S=10 ground state and single-molecul

R. Franco, M. S. Figueira, M. E. Foglio

The Periodic Anderson Model (PAM) in the $U\to\infty$ limit has been studied in a previous work employing the cumulant expansion with the hybridization as perturbation (M. S. Figueira, M. E. Foglio and G. G. Martinez, Phys. Rev. B \textbf{50}, 17933 (1994)). When the total number of electrons $N_{t}$ is calculated as a function of the chemical potential $μ$

Gabor Zala, B. N. Narozhny, I. L. Aleiner

We consider the correction to conductivity of a 2D electron gas due to electron-electron interaction in the parallel magnetic field at arbitrary relation between temperature and the elastic mean free time. The correction exhibits non-trivial dependence on both temperature and the field. This dependence is determined by the Fermi liquid constant, which accoun

V. S. Oudovenko, G. Kotliar

We investigate the thermoelectric properties of a system near a pressure driven Mott-Hubbard transition. The dependence of the thermopower and the figure of merit on pressure and temperature within a degenerate Hubbard model for integer filling n=1 is calculated using dynamical mean field theory. Quantum Monte Carlo method is used to solve the impurity model

Christian Tanguy

Excitons have recently been shown to deviate from pure bosons at densities a hundred times smaller than the Mott density. The corresponding calculations relied on the unscreened excitonic ground state wavefunction. A consistent inclusion of screening, by use of the fundamental eigenfunction of the Hulthén potential, vindicates this approximation.

George C. M. A Ehrhardt, Alan J. Bray

We consider an arbitrary Gaussian Stationary Process X(T) with known correlator C(T), sampled at discrete times T_n = n ΔT. The probability that (n+1) consecutive values of X have the same sign decays as P_n \sim \exp(-θ_D T_n). We calculate the discrete persistence exponent θ_D as a series expansion in the correlator C(ΔT) up to 14th order, and extrapolate

M. Grueninger, M. Windt, T. Nunner, C. Knetter

Magnetic excitations in two-leg S=1/2 ladders are studied both experimentally and theoretically. Experimentally, we report on the reflectivity, the transmission and the optical conductivity sigma(omega) of undoped La_x Ca_14-x Cu_24 O_41 for x=4, 5, and 5.2. Using two different theoretical approaches (Jordan-Wigner fermions and perturbation theory), we calcu

Yuriy I. Kuzmin

The influence of the fractal clusters of a normal phase, which act as pinning centers, on the dynamics of magnetic flux in percolative type-II superconductor is considered. The voltage-current characteristics of such a superconductor are obtained taking into account the effect of fractal properties of cluster boundaries on the magnetic flux trapping. It is r

Enzo Orlandini, Somendra M. Bhattacharjee, Davide Marenduzzo, Amos Maritan

Recent theoretical predictions on DNA mechanical separation induced by pulling forces are numerically tested within a model in which self-avoidance for DNA strands is fully taken into account. DNA strands are described by interacting pairs of self avoiding walks (SAW) which are pulled apart by a force applied at the two extremities. The whole phase diagram i

M. Garst, T. Kopp

We investigate the distribution of the supercurrent through a chaotic quantum dot which is strongly coupled to two superconductors when the Thouless energy is large compared to the superconducting energy gap. The distribution function of the critical currents P(I_c) is known to be Gaussian in the limit of large channel number N. For N=1, we present an analyt

H. K. Lee, H. -W. Lee, D. Kim

We present a method to derive macroscopic fluid-dynamic models from microscopic car-following models via a coarse-graining procedure. The method is first demonstrated for the optimal velocity model. The derived macroscopic model consists of a conservation equation and a momentum equation, and the latter contains a relaxation term, an anticipation term, and a

Laurent Proville

The self-organization of a chemi-sorbed mono-layer is studied as a two dimensional ordering process in presence of surface stress. As proved previously for a single phase separation, a steady surface state is yielded from the competition between the domain boundary energy and the surface stress elastic energy. In the present letter, the resulting patterns ar

L. Hedin, J. D. Lee

The conditions behind the sudden approximation are critically examined. The fuzzy band expression is derived in detail from first principles. We go beyond the sudden approximation to account for both extrinsic losses and interference effects. In an extension of earlier work we discuss both core and valence satellites including both intrinsic and extrinsic am

O. Pulkkinen, J. Merikoski

We present exact and asymptotic results for clusters in the one-dimensional totally asymmetric exclusion process (TASEP) with two different dynamics. The expected length of the largest cluster is shown to diverge logarithmically with increasing system size for ordinary TASEP dynamics and as a logarithm divided by a double logarithm for generalized dynamics,

Tomoya Isoshima

We propose a method to create a vortex in BEC utilizing the spin degree of freedom. We consider the optical plug at the center of the vortex, which makes the vortex-creation process stable. We also investigate the instability of the halfway state to complete vortex state without the optical plug.

H. Aoki, M. Koshino, D. Takeda, H. Morise

Electronic band structure for electrons bound on periodic minimal surfaces is differential-geometrically formulated and numerically calculated. We focus on minimal surfaces because they are not only mathematically elegant (with the surface characterized completely in terms of &#34;navels&#34;) but represent the topology of real systems such as zeolites and n

T. Inami, S. Ishihara, H. Kondo, J. Mizuki

We report resonant inelastic x-ray scattering experiments of the orbital ordered manganite LaMnO3. When the incident photon energy is tuned near the Mn K absorption edge, the spectra reveal three features at 2.5 eV, 8 eV and 11 eV. The 8 eV and 11 eV peaks are considered charge-transfer type excitations. On the other hand, theoretical calculations identify t

Yoshiyuki Shibayama, Masaya Yamazaki, Hanako Isshiki, Keiya Shirahama

The Wigner crystal on liquid He accompanies with periodic corrugation of the He surface; dimples. The dynamics of the crystal is coupled with the motion and the deformation of the dimples. Nonlinear phenomena found in AC Corbino conductivity are attributed to the collective sliding of the electrons out of the dimples. In order to inspect the dynamical transi

Constantino Tsallis, Ernesto P. Borges, Fulvio Baldovin

After a brief review of the present status of nonextensive statistical mechanics, we present a conjectural scenario where mixing (characterized by the entropic index $q_{mix} \le 1$) and equilibration (characterized by the entropic index $q_{eq} \ge 1$) play central and inter-related roles, and appear to determine {\it a priori} the values of the relevant in

Martin Plihal, David C. Langreth, Peter Nordlander

It is shown that the rate limiting time constant for the formation of the Kondo state in a quantum dot can be extracted analytically from known perturbation theoretic results. The prediction obtained is verified via numerical simulations in the noncrossing approximation.

Sam F. Edwards, Moshe Schwartz

We consider non-linear stochastic field equations such as the KPZ equation for deposition and the noise driven Navier-Stokes equation for hydrodynamics. We focus on the Fourier transform of the time dependent two point field correlation, $Φ_{\bf{k}}(t)$. We employ a Lagrangian method aimed at obtaining the distribution function of the possible histories of t

Douglas C. Leonard, Alexei V. Filippenko, Elinor L. Gates, Weidong Li

We present 30 optical spectra and 49 photometric epochs sampling the first 517 days after discovery of supernova (SN) 1999em, and derive its distance through the expanding photosphere method (EPM). SN 1999em is shown to be a Type II-plateau (II-P) event, with a photometric plateau lasting until about 100 days after explosion. We identify the dominant ions re

Douglas P. Finkbeiner, David J. Schlegel, Curtis Frank, Carl Heiles

We present the first tentative detection of spinning dust emission from specific astronomical sources. All other detections in the current literature are statistical. The Green Bank 140 foot telescope was used to observe 10 dust clouds at 5, 8, and 10 GHz. In some cases, the observed emission was consistent with the negative spectral slope expected for free-

Pauline Barmby, Kathryn M. Perrett, Terry J. Bridges

The M31 globular cluster candidate 037-B327 has long been known to be an extremely red, non-stellar object. The first published spectrum of this object is used to confirm that it is a globular cluster belonging to M31, with rather typical values of v_r = -338 +/- 12 km/s and [Fe/H]= -1.07 +/- 0.20 dex. Using the spectroscopic metallicity to predict the intri

S. Hinkley, M. Im

Recent studies based on line indices of nearby early-type galaxies suggest that stars in the galaxies&#39; inner part may be younger and more metal rich than stars in the outer part. If confirmed, the finding has a profound implication for the formation and evolution of early-type galaxies, since such age gradients naturally arise if merging played an import

R. C. Telfer, W. Zheng, G. A. Kriss, A. F. Davidsen

We use a sample of 332 Hubble Space Telescope spectra of 184 QSOs with z > 0.33 to study the typical ultraviolet spectral properties of QSOs, with emphasis on the ionizing continuum. Our sample is nearly twice as large as that of Zheng et al. (1997) and provides much better spectral coverage in the extreme ultraviolet (EUV). The overall composite continuum c

Qingjuan Yu

Since many or most galaxies have central massive black holes (BHs), mergers of galaxies can form massive binary black holes (BBHs). In this paper, we study the evolution of massive BBHs in realistic galaxy models, using a generalization of techniques used to study tidal disruption rates around massive BHs. The evolution of BBHs depends on BH mass ratio and h

D. Hutsemekers, H. Lamy

Correlations between BAL QSO intrinsic properties and polarization have been searched for. Some results are summarized here, providing possible constraints on BAL outflow models.

Andrew J. Young, Andrew S. Wilson, Yuichi Terashima, Keith A. Arnaud

We report Chandra ACIS and quasi-simultaneous RXTE observations of the nearby, powerful radio galaxy Cygnus A, with the present paper focusing on the properties of the active nucleus. In the Chandra observation, the hard (> a few keV) X-ray emission is spatially unresolved with a size \approxlt 1 arcsec (1.5 kpc, H_0 = 50 km s^-1 Mpc^-1) and coincides with t

J. W. Truran, S. Burles, J. J. Cowan, C. Sneden

Nucleocosmochronology involves the use of the abundances of radioactive nuclear species and their radiogenic decay daughters to establish the finite age of the elements and the time scale for their formation. While there exist radioactive products of several specific nucleosynthesis mechanisms that can reveal the histories of these mechanisms, it is the long

Philip M. Hinz, William F. Hoffmann, Joseph L. Hora

Physical models of circumstellar disks surrounding pre-main sequence stars are currently constrained primarily by the spectral energy distribution (SED) of the system. Here we present first results from a survey of nearby Herbig Ae stars using nulling interferometry. We measure the spatial extent of the mid-IR emission for the stars HD 150193, HD 163296, and

N. Ivanova, Ph. Podsiadlowski, H. Spruit

We present detailed simulations of the interaction of a stream emanating from a mass-losing secondary with the core of a massive supergiant in the slow merger of the two stars inside a common envelope. The dynamics of the stream can be divided into a ballistic phase, starting at the L_1 point, and a hydrodynamical phase where the stream interacts strongly wi

D. E. Harris, H. Krawczynski

The emission processes responsible for the observed X-rays from radio jets are commonly believed to be non-thermal, but in any particular case, it is unclear if synchrotron emission or one or more varieties of inverse Compton emission predominates. We present a formulation of inverse Compton emission from a relativistically moving jet (``IC/beaming&#39;&#39;

Ruth Durrer

This is a review of the theory of CMB anisotropies, an updated version of a course given at the troisieme cycle de la Suisse Romande. An introduction to gauge invariant cosmological perturbation theory is given and the theory CMB anisotropies is develiped in this context. Simple analytical approximations for the acoustic peak positions for adiabatic and isoc

E. Pfahl, S. Rappaport, Ph. Podsiadlowski, H. Spruit

We investigate an interesting new class of high-mass X-ray binaries (HMXBs) with long orbital periods (P_orb > 30 days) and low eccentricities (e <~ 0.2). The orbital parameters suggest that the neutron stars in these systems did not receive a large impulse, or ``kick,&#39;&#39; at the time of formation. We develop a self-consistent phenomenological picture

H. Rebel

By a short tour through the exciting field of very high-energy and ultra high-energy cosmic rays studies, a brief review is given about the current questions approached, in particular by the KASCADE experiment and the Pierre Auger project. The present status of the investigations of the knee region of the cosmic ray spectrum by KASCADE is presented and open

Y. Izotov, F. Chaffee, C. Foltz, K. Fricke

The results of the N/O abundance determination in a sample of low-metallicity blue compact dwarf (BCD) galaxies based on new spectroscopic observations with large telescopes (Keck, VLT, MMT, 4m KPNO) are presented. We show that the N/O abundance ratio is constant at lowest metallicities < Zsun/20, confirming previous findings and strongly supporting the orig

T. X. Thuan, A. Lecavelier des Etangs, Y. I. Izotov

New FUSE far-UV spectroscopy of the nearby metal-deficient (Zsun/8) cometary Blue Compact Dwarf (BCD) galaxy Markarian (Mrk) 59 is discussed. The data are used to investigate element abundances in its interstellar medium. The H I absorption lines are characterized by narrow cores which are interstellar in origin and by broad wings which are stellar in origin

V. I. Slysh, V. Migenes, I. E. Val&#39;tts, S. Yu. Lyubchenko

W75N is a star-forming region containing various ultracompact HII regions and OH, water, and methanol maser emission. Our VLBA map shows that the OH masers are located in a thin disk rotating around an O-star which is the exciting star of the ultracompact HII region VLA1. A separate set of maser spots is connected with the ultracompact HII region VLA2. The r

A. Rodriguez-Ardila, S. M. Viegas, M. G. Pastoriza, L. Prato

We obtained 0.8-2.4 micron spectra at a resolution of 320 km/s of four narrow-line Seyfert 1 galaxies in order to study the near-infrared properties of these objects. We focus on the analysis of the FeII emission in that region and the kinematics of the low-ionization broad lines. We found that the 1 micron FeII lines (9997 A, 10501 A, 10863 A and 11126 A) a

P. B. Marty, J. Schultz, C. Bayer, A. Fritz

The latest all-sky survey in hard X-ray band was performed by the HEAO-1 satellite (13-80 keV) with an angular resolution of 24x48 arcmin. A diffuse hard X-Ray background (HXB) was detected between 3 and 50 keV. The main scientific goal of In.XS is to resolve a large fraction of this HXB into individual sources. As no distortion by Compton up-scattering is s

Henk Hoekstra, H. K. C. Yee, Michael D. Gladders

The Red-Sequence Cluster Survey (RCS) is a 100 deg^2 galaxy cluster survey designed to provide a large sample of optically selected clusters of galaxies with redshifts 0.1<z<1.4. The survey data are also useful for a variety of lensing studies. Several strong lensing clusters have been discovered so far, and follow up observations are underway. In these proc

Martin Elvis

The model I recently proposed for the structure of quasars offers to unify the many aspects of Type 1 AGN: emission lines, absorption lines and reflection features. This makes the model heavily overconstrained by observation and readily tested. Here I first outline the model, and then concentrate on how the model answers objections raised since publication -

S. Demers, P. Battinelli

We present the latest results of our ongoing homogeneous cool C star survey of Local Group dwarf galaxies. We apply our two color photometric technique to the study of two small galaxies: the Sagittarius dwarf (SagDIG) and Leo I. We identify 16 C stars in SagDIG and 13 C stars in Leo I. Even though both galaxies have a known C star population, we identify 7

P. T. de Zeeuw, M. Bureau, E. Emsellem, R. Bacon

Early results are reported from the SAURON survey of the kinematics and stellar populations of a representative sample of nearby E, S0 and Sa galaxies. The survey is aimed at determining the intrinsic shape of the galaxies, their orbital structure, the mass-to-light ratio as a function of radius, the age and metallicity of the stellar populations, and the fr

Ilse van Bemmel, Peter Barthel

Far-infrared photometry of broad-line radio galaxies shows this class of AGN to consist of many hot and some cool infrared emitters, with peaks in their spectral energy distributions around 25 micron or longward of 60 micron, respectively. Quantitative analysis indicates that this distribution relates to a substantial dispersion in the strength of the cool d

Xavier Dupac

The map-making process of Cosmic Microwave Background data involves linear inversion problems which cannot be performed by a brute force approach for the large timelines of most modern experiments. We present optimal iterative map-making methods, both COBE and Wiener, and apply these methods on simulated data. They produce very well restored maps, by removin

A. Karastergiou, A. von Hoensbroech, M. Kramer, D. R. Lorimer

We present the first results from a programme of multi-frequency simultaneous single pulse observations carried out as part of the European Pulsar Network. We detail the main data analysis methods and apply them to simultaneous observations of the strong pulsar B0329+54 at 1.4 and 2.7 GHz using the Jodrell Bank and Effelsberg radio telescopes respectively. T

Garret Cotter, Helen J. Buttery, Steve Rawlings, Steve Croft

We present the results of radio, optical and near-infrared observations of the field of TOC J0233.3+3021, a cluster of milliJansky radiosources from the TexOx Cluster survey. In an observation of this field with the Ryle Telescope (RT) at 15 GHz, we measure a decrement in the cosmic microwave background (CMB) of $-675 \pm 95 μ$Jy on the RT&#39;s $\approx$ 0.

Rosa M. Gonzalez Delgado

Observations at ultraviolet, optical and near-infrared wavelengths have shown the existence of recent star formation in the nuclear regions of Seyfert 2 (Sy2) galaxies that suggest a connection between the Starburst and the Seyfert phenomenon. According with the standard unified models of AGN circumnuclear starbursts also have to be present (and in the same

Katherine Blundell, Amy Mioduszewski, Tom Muxlow, Philipp Podsiadlowski

We have imaged the X-ray binary SS433 with unprecedented Fourier-plane coverage at 6cm using simultaneously the VLBA, MERLIN, and the VLA, and also at 20cm with the VLBA. At both wavelengths we have securely detected smooth, low-surface brightness emission having the appearance of a `ruff&#39; or collar attached perpendicularly to the well-studied knotty jet

A. Maeder, R. Behrend

We briefly describe the three existing scenarios for forming massive stars and emphasize that the arguments often used to reject the accretion scenario for massive stars are misleading. It is usually not accounted for the fact that the turbulent pressure associated to large turbulent velocities in clouds necessarily imply relatively high accretion rates for

Rob Fender

In this review I summarise the observational connections between accretion and relativistic outflows -- jets -- in X-ray binaries. I argue that jets are likely to be a fairly ubiquitous property of X-ray binaries as a whole, an assertion which can be tested by further observations of the Atoll-type X-ray binaries. I discuss broad patterns that are emerging f

Takayuki Tatekawa, Momoko Suda, Kei-ichi Maeda, Hiroto Kubotani

We study an effect of inhomogeneity of density distribution of the Universe. We propose a new Lagrangian perturbation theory with a backreaction effect by inhomogeneity. The inhomogeneity affects the expansion rate in a local domain and its own growing rate. We numerically analyze a one-dimensional plane-symmetric model, and calculate the probability distrib

Alberto Noriega-Crespo, Peter M. Garnavich

A key ingredient in understanding the dynamics of stellar outflows is their proper motion. We have used optical images in the [SII] emission at 6717/31 A and the red Digitized Palomar Observatory Sky Survey (DSS) plates to determine the proper motion of HH 7-11 system and the optical knot of Cep E (HH 377). The DSS plate measurements span nearly 37 years for

Masashi Chiba

We investigate the effects of numerous dark matter subhalos in a galaxy-sized halo on the events of strong lensing, to assess their presence as expected from the cold dark matter scenario. Lens galaxies are represented by a smooth ellipsoid in an external shear field and additional cold dark matter subhalos taken from Monte Carlo realizations which accord wi

J. Patrick Henry

We describe the ensemble X-ray properties of high redshift clusters with emphasis on changes with respect to the local population. Cluster X-ray luminosity evolution is detected in five nearly independent surveys. The relevant issue now is characterizing this evolution. Cluster temperature evolution provides constraints on the dark matter and dark energy con

Axel Brandenburg

The advantages of high-order finite difference scheme for astrophysical MHD and turbulence simulations are highlighted. A number of one-dimensional test cases are presented ranging from various shock tests to Parker-type wind solutions. Applications to magnetized accretion discs and their associated outflows are discussed. Particular emphasis is placed on th

Manasse R. Mbonye

We explore the dynamics of neutrinos in a vacuum dominated cosmology. First we show that such a geometry will induce a phase change in the eigenstates of a massive neutrino and we calculate the phase change. We also calculate the delay in the neutrino flight times in this geometry. Applying our results to the presently observed background vacuum energy densi

K. Maeda, T. Nakamura, K. Nomoto, P. A. Mazzali

Aspherical explosion models for the hypernova (hyper-energetic supernova) SN 1998bw are presented. Nucleosynthesis in aspherical explosions is examined with a two-dimensional hydrodynamical code and a detailed nuclear reaction network. Aspherical explosions lead to a strong $α$-rich freezeout, thus enhancing the abundance ratios [$^{44}$Ca, $^{48}$Ti, and $^

S. -R. Eric Yang, Ziqiang Wang, A. H. MacDonald

We examine the long wave length limit of the self-consistent Hartree-Fock approximation irreducible static density-density response function by evaluating the charge induced by an external charge. Our results are consistent with the compressibility sum rule and inconsistent with earlier work that did not account for consistency between the exchange-local-fie

Steen H. Hansen, Martin Kunz

Direct observations provide constraints on the first two derivatives of the inflaton potential in slow roll models. We discuss how present day observations, combined with the flow equations in slow roll parameter space, provide a non-trivial constraint on the third derivative of the inflaton potential. We find a lower bound on the third derivative of the inf

Franz Luef, Gerald Teschl

We present a new oscillation criterion to determine whether the number of eigenvalues below the essential spectrum of a given Jacobi operator is finite or not. As an application we show that Kenser&#39;s criterion for Jacobi operators follows as a special case.

B. Uchoa, G. G. Cabrera

The distribution of magnetic moments in finite ferromagnetic bodies was first investigated by Landau and Lifshitz in a famous paper [\textit{Phys. Z. Soviet Union}, \textbf{8}, 153 (1935)], where they obtained the domain structure of a ferromagnetic crystal at low temperatures, in the regime of saturated magnetization. In this article, we investigate the gen

Thereza Paiva, Gokhan Esirgen, Richard T. Scalettar, Carey Huscroft

We study a simple model for $f$-electron systems, the three-dimensional periodic Anderson model, in which localized $f$ states hybridize with neighboring $d$ states. The $f$ states have a strong on-site repulsion which suppresses the double occupancy and can lead to the formation of a Mott-Hubbard insulator. When the hybridization between the $f$ and $d$ sta

Yu-Yu Chen, Zhen Ye

Acoustic propagation and scattering in water containing many parallel air-filled cylinders is studied. Two situations are considered and compared: (1) wave propagating through the array of cylinders, imitating a traditional experimental setup, and (2) wave transmitted from a source located inside the ensemble. We show that waves can be blocked from propagati