December 2001 arXiv papers — page 25

E895 Collaboration, P. Danielewicz

Proton elliptic flow is studied as a function of impact-parameter $b$, for two transverse momentum cuts in 2 - 6 AGeV Au + Au collisions. The elliptic flow shows an essentially linear dependence on b (for $1.5 < b < 8$ fm) with a negative slope at 2 AGeV, a positive slope at 6 AGeV and a near zero slope at 4 AGeV. These dependencies serve as an important con

Robert Conte, Micheline Musette

For the master Painlevé equation P6(u), we define a consistent method, adapted from the Weiss truncation for partial differential equations, which allows us to obtain the first degree birational transformation of Okamoto. Two new features are implemented to achieve this result. The first one is the homography between the derivative of the solution $u$ and a

Idun Reiten, Michel Van den Bergh

In this paper we classify noetherian hereditary abelian categories satisfying Serre duality in the sense of Bondal and Kapranov. As a consequence we obtain a classification of saturated noetherian hereditary categories. As a side result we show that when our hereditary categories have no nonzero projectives or injectives, then the Serre duality property is e

Alexandru Tupan

In this paper we prove a theorem about the coefficients in a block of a half integral weight modular form. We show that the result of Serre and Stark for weight 1/2 forms does not generalize to higher higher weights. Let f be a half integral weight cusp form of weight at leat 3/2. We consider blocks of coefficients of f and prove that, under some weak assump

Farshid Hajir, Christian Maire

We consider p-extensions of number fields such that the filtration of the Galois group by higher ramification groups is of prescribed finite length. We extend well-known properties of tame extensions to this more general setting; for instance, we show that these towers, when infinite, are ``asymptotically good&#39;&#39; (an explicit bound for the root discri

Juergen Klueners, Gunter Malle

We obtain strong information on the asymptotic behaviour of the counting function for nilpotent Galois extensions with bounded discriminant of arbitrary number fields. This extends previous investigations for the case of abelian groups. In particular, the result confirms a conjecture by the second author on this function for arbitrary groups in the nilpotent

Dev Sinha

Local cohomology techniques in equivariant homotopy theory, introduced by John Greenlees, may be applied to understand homology of classifying spaces through other equivariant data. In this paper we relate the local cohomology filtration to the families filtration. By doing so, we may identify geometry codified by the local cohomology filtration in the setti

Shlomo Gelaki, Edward S. Letzter

In formulating a generalized framework to study certain noncommutative algebras naturally arising in representation theory, K. A. Brown asked if every finitely generated Hopf algebra satisfying a polynomial identity was finite over a normal commutative Hopf subalgebra. In this note we show that Radford&#39;s biproduct, applied to the enveloping algebra of th

Carlos A. Torre

We review the basic definitions and properties concerning smooth structures, convenient spaces, diffeological spaces and tangent structures. The relation betwen them is described. A tangent structure is constructed for each pre-convenient space. This one is proved to be convenient iff the space and the tangent fibres coincide. Some basic comments on the rela

Jean-Louis Loday

We construct an addition and a multiplication on the set of planar binary trees, closely related to addition and multiplication on the integers. This gives rise to a new kind of (noncommutative) arithmetic theory. The price to pay for this generalization is that, first the addition is not commutative, second the multiplication is distributive with the additi

A. J. van Es, H. -W. Uh

We derive asymptotic normality of kernel type deconvolution estimators of the density, the distribution function at a fixed point, and of the probability of an interval. We consider the so called super smooth case where the characteristic function of the known distribution decreases exponentially. It turns out that the limit behavior of the pointwise estimat

Don Coppersmith, David Gamarnik, Maxim Sviridenko

We consider the following long range percolation model: an undirected graph with the node set $\{0,1,...,N\}^d$, has edges $(\x,\y)$ selected with probability $\approx β/||\x-\y||^s$ if $||\x-\y||>1$, and with probability 1 if $||\x-\y||=1$, for some parameters $β,s>0$. This model was introduced by Benjamini and Berger, who obtained bounds on the diameter of

Hiroaki Terao

Let $Δ$ be a finite set of nonzero linear forms in several variables with coefficients in a field $\mathbf K$ of characteristic zero. Consider the $\mathbf K$-algebra $C(Δ)$ of rational functions generated by $\{1/α\mid α\in Δ\}$. Then the ring $\partial(V)$ of differential operators with constant coefficients naturally acts on $C(Δ)$. We study the graded $\

Gerald V. Dunne

The induced fractional fermion number at zero temperature is topological (in the sense that it is only sensitive to global asymptotic properties of the background field), and is a sharp observable (in the sense that it has vanishing rms fluctuations). In contrast, at finite temperature, it is shown to be generically nontopological, and not a sharp observable

C. I. Lazaroiu, R. Roiban

We perform the Batalin-Vilkovisky analysis of gauge-fixing for graded Chern-Simons theories. Upon constructing an appropriate gauge-fixing fermion, we implement a Landau-type constraint, finding a simple form of the gauge-fixed action. This allows us to extract the associated Feynman rules taking into account the role of ghosts and antighosts. Our gauge-fixi

Jaume Garriga, Takahiro Tanaka

Bucher [Bucher2001] has recently proposed an interesting brane-world cosmological scenario where the ``Big Bang&#39;&#39; hypersurface is the locus of collision of two vacuum bubbles which nucleate in a five dimensional flat space. This gives rise to an open universe, where the curvature can be very small provided that $d/R_0$ is sufficiently large. Here, d

Stefano Bellucci, Anton Galajinsky

We consider quantum N=2 string embedded into the N=4 topological framework from the perspective of the old covariant quantisation. Making use of the causality and cyclic symmetry of tree amplitudes we argue that no Lorentz covariant boson emission vertex can be constructed within the N=4 topological formalism.

G. S. Danilov

The multi-loop amplitudes for the closed, oriented superstring are represented by finite dimensional integrals of explicit functions calculated through the super-Schottky group parameters and interaction vertex coordinates on the supermanifold. The integration region is proposed to be consistent with the group of the local symmetries of the amplitude and wit

N. N. Khuri, A. Martin, T. T. Wu

We stress that in contradiction with what happens in space dimensions $n \geq 3$, there is no strict bound on the number of bound states with the same structure as the semi-classical estimate for large coupling constant and give, in two dimensions, examples of weak potentials with one or infinitely many bound states. We derive bounds for one and two dimensio

Jose Alexandre Nogueira, Pedro Leite Barbieri

We consider the effects of homogeneous Dirichlet&#39;s boundary conditions on two infinite parallel plane surfaces separated by a small distance {\it a}. We find that although spontaneous symmetry breaking does not occur for the theory of a massless, quartically self-interacting real scalar field, the theory becomes a theory of a massive scalar field.

T. Csorgo, M. Gyulassy, D. Kharzeev

We explore the possibility that novel geometrical structures analogous to carbon Fullerenes may exist in Nature on the femtometer scale. QCD predicts the existence of special topological gluon field configurations called baryon junctions and anti-junctions. Here we show that femto-scale structures, networks or closed (gluon field) cages, can be constructed i

A. Ster, T. Csorgo

The final state of $Au + Au$ collisions at sqrt{s}=130 AGeV at RHIC has been reconstructed within the framework of the Buda-Lund hydro model, by performing a simultaneous fit to preliminary PHENIX and STAR data on two-particle Bose-Einstein correlations and identified single particle spectra. The Hubble constant of the expanding final state of this heavy ion

Gustavo Burdman

I discuss recent progress in our understanding of exclusive rare and semileptonic decays. I show the impact of HQET when combined with the predictions in the Large Energy Limit of QCD, focusing first on applications to $B\to K^*\ell^+\ell^+$. I also discuss the constraints on semileptonic form-factors that appear in HQET/LEET with the use of radiative decay

Edmond L. Berger

It has been known for a long time that the cross section for bottom-quark $b$ production at hadron collider energies exceeds theoretical expectations. An additional contribution from pair-production of light gluinos $\tilde{g}$, of mass 12 to 16 GeV, with two-body decays into bottom quarks and light bottom squarks $\tilde{b}$, helps to obtain a $b$ productio

Sean Fleming

In this talk I review NRQCD predictions for the production of charmonium at the Tevatron. After a quick presentation of the NRQCD factorization formalism for production and decay I review some old results and discuss how they compare to recent data. Following this I discuss some recent work done with Adam Leibovich and Ira Rothstein.

M. Salle, J. Smit, J. C. Vink

In numerical simulations studying preheating in the classical approximation there is the problem how to derive the classical initial conditions from the quantum vacuum fluctuations. In past treatments, the initial conditions often put an energy density into the classical field of order of the cutoff, leading to a divergent temperature after thermalization. W

Dmitri Grigoriev

We discuss topological transitions during parametric resonance in the gauge sector of electroweak theory. It is shown that the resonance leads to separation of topological indices of the gauge and Higgs fields, resulting in topological transitions of non-sphaleron nature.

Hong-an Peng

In this paper we first emphasize the importance of the Pomeron (IP) for its asymptotically saturation the unitarity condition alone. After proper modified the field theory model for IP developed by Landshoff and Nochtmann, we argue that the exchange of IP in high energy $h-h&#39;$ scattering embodies the hypothesis of the maximum non-perturbative strong inte

S. Todorova-Nova

Inclusive measurement of $J/Ψ$ (DELPHI), search for $η_b$ (ALEPH) and measurement of the cross-section of the double-tagged $γγ$ events (ALEPH) are briefly overviewed.

W. J. Metzger

In hadronic Z decays, we compare Bose-Einstein correlations in \Pgpz pairs with those in identical charged pion pairs. We also measure Bose-Einstein correlations in triplets of identical charged pions. From the first study, the source radius is found to be smaller for \Pgpz-\Pgpz than for \Pgppm-\Pgppm, as would be expected, e.g., in a string model. However,

A. Ali, A. Ya. Parkhomenko

The effective $η^\prime g^* g^*$ vertex is studied in the standard (Brodsky-Lepage) and modified hard scattering approaches for arbitrary gluon virtualities in the time-like and space-like regions. The contribution of the gluons in the $η^\prime$-meson is taken into account, and the wave-function is constrained using data on the electromagnetic transition fo

Marek Karliner

We discuss the puzzling experimental results on baryon-antibaryon production in e+e- annihilation close to the threshold, in particular the fact that sigma(e+e- --> nbar n) is somewhat greater than sigma(e+e- --> pbar p). We discuss an interpretation in terms of a two-step process, via an intermediate coherent isovector state serving as an intermediary betwe

F. Moortgat, S. Abdullin, D. Denegri

We discuss the possibilities to observe the decays of heavy SUSY Higgs bosons into supersymmetric particles at the LHC. Such an observation would be of interest either in a discovery search if sparticle modes are the dominant ones, or in a study of additional decay modes, bringing information on the SUSY scenario potentially at work. We will focus on the mos

D. Denegri, V. Drollinger, R. Kinnunen, K. Lassila-Perini

This work summarises the present understanding of the expected MSSM SUSY Higgs reach for CMS. Many of the studies presented here result from detailed detector simulations incorporating final CMS detector design and response. With 30 fb-1 the h -> gamma,gamma and h -> bb channels allow to cover most of the MSSM parameter space. For the massive A,H,H+ MSSM Hig

M. Golterman, S. Peris, B. Phily, E. de Rafael

We consider a simple model of large-Nc QCD defined by a spectrum consisting of an infinite set of equally spaced zero-width vector resonances. This model is an excellent theoretical laboratory for investigating certain approximation schemes which have been used recently in calculations of hadronic parameters, such as the Minimal Hadronic Approximation. We al

M. Cacciari, V. Del Duca, S. Frixione, Z. Trocsanyi

In this talk we describe the order-$\as$ corrections to the total cross section and to jet rates in $γ^* γ^* \to$ hadrons for the process $\epem\to\epem +$ hadrons. We use a next-to-leading order general-purpose partonic Monte Carlo event generator that allows the computation of a rate differential in the produced leptons and hadrons. We compare our results

X. -H. Guo, A. W. Thomas

Hyperfine splittings between the heavy vector (D*, B*) and pseudoscalar (D, B) mesons have been calculated numerically in lattice QCD, where the pion mass (which is related to the light quark mass) is much larger than its physical value. Naive linear chiral extrapolations of the lattice data to the physical mass of the pion lead to hyperfine splittings which

J. P. Ma

Using heavy quark effective theory a factorized form for inclusive production rate of a heavy meson can be obtained, in which the nonperturbative effect related to the heavy meson can be characterized by matrix elements defined in the heavy quark effective theory. Using this factorization, predictions for the full spin density matrix of a spin-1 and spin-2 m

Robert D. Pisarski

I give a brief review of the Polyakov Loops Model and tests thereof. I concentrate especially on how in a pure SU(N) gauge theory, Polyakov loops with Z(N) charges two and three affect the effective potential for charge-one loops.

Gabriella Pasztor, Maxim Perelstein

If a contact interaction type correction to a Standard Model process is observed, studying its detailed properties can provide information on the fundamental physics responsible for it. Assuming that such a correction has been observed in lepton pair production at a 500 GeV - 1 TeV linear collider, we consider a few possible models that could explain it, suc

Akos Csilling

Charm production is studied in deep-inelastic electron-photon scattering using OPAL data at e+e- centre-of-mass energies from 183 to 209 GeV. Charm quarks are identified by exclusive reconstruction of D* mesons. The cross-section of D* production is measured in a restricted kinematic region, and then extrapolated to the total charm production cross-section a

S. Kluth

Experimental tests of QCD predictions for event shape distributions combining contributions from hard and soft processes are discussed. The hard processes are predicted by perturbative QCD calculations. The soft processes cannot be calculated directly using perturbative QCD, they are treated by a power correction model based on the analysis of infrared renor

Albert De Roeck, John Ellis, Fabiola Gianotti

We summarize the physics motivations for future accelerators at CERN. We argue that (a) a luminosity upgrade for the LHC could provide good physics return for a relatively modest capital investment, (b) CLIC would provide excellent long-term perspectives within many speculative scenarios for physics beyond the Standard Model, (c) a Very Large Hadron Collider

J. Oppenheim

The connection between gravity and thermodynamics is explored. Examining a perfect fluid in gravitational equilibrium we find that the entropy is extremal only if Einstein&#39;s equations are satisfied. Conversely, one can derive part of Einstein&#39;s equations from ordinary thermodynamical considerations. This allows the theory of this system to be recast

M. Pokorny, M. Brooks, B. Glendenning, G. Harris

The control system (TICS) for the test interferometer being built to support the development of the Atacama Large Millimeter Array (ALMA)will itself be a prototype for the final ALMA array, providing a test for the distributed control system under development. TICS will be based on the ALMA Common Software (ACS) (developed at the European Southern Observator

Robert Haslinger, Robert Joynt

It is shown that for materials near the metal insulator transition, inelastic losses can give rise to substantial changes on a scale of 10-100 meV in the observed lineshape compared to the intrinsic spectral function of an electron photoemitted from a solid. These changes arise from the frequency dependence of the loss function, similar to those directly obs

Richard Kerner

We show how growth by agglomeration can be described by means of algebraic or differential equations which determine the evolution of probabilities of various local configurations. The minimal fluctuation condition is used to define vitrification. Our methods have been successfully used for the description of glass formation.

V. A. Khodel, J. W. Clark

The problem of pairing in anisotropic electron systems possessing patches of fermion condensate in the vicinity of the van Hove points is analyzed. Attention is directed to opportunities for the occurrence of non-BCS pairing correlations between the states belonging to the fermion condensate. It is shown that the physical emergence of such pairing correlatio

John D. Weeks

This article reviews a new and general theory of nonuniform fluids that naturally incorporates molecular scale information into the classical van der Waals theory of slowly varying interfaces. The method optimally combines two standard approximations, molecular (mean) field theory to describe interface formation and linear response (or Gaussian fluctuation)

Cristiano De Michele, Francesco Sciortino

Generation of equilibrium configurations is the major obstacle for numerical investigation of the slow dynamics in supercooled liquid states. The parallel tempering (PT) technique, originally proposed for the numerical equilibration of discrete spin-glass model configurations, has recently been applied in the study of supercooled structural glasses. We prese

I. M. Abu-Shiekah, O. Bakharev, H. B. Brom, J. Zaanen

The experimental observations of stripes in superconducting cuprates and insulating nickelates clearly show the modulation in charge and spin density. However, these have proven to be rather insensitive to the harmonic structure and (site or bond) ordering. Using 139La NMR in La2NiO4.17, we show that in the 1/3 hole doped nickelate below the freezing tempera

H. M. Harreis, A. A. Kornyshev, C. N. Likos, H. Loewen

The pair interaction between two stiff parallel linear DNA molecules depends not only on the distance between their axes but on their azimuthal orientation. The positional and orientational order in columnar B-DNA assemblies in solution is investigated, based on the DNA-DNA electrostatic pair potential that takes into account DNA helical symmetry and the amo

Richard Berndt, Joerg Kliewer, S. Crampin

The electronic structure of artificial Mn atom arrays on Ag(111) is characterized in detail with scanning tunnelling spectroscopy and spectroscopic imaging at low temperature. We demonstrate the degree to which variations in geometry may be used to control spatial and spectral distributions of surface state electrons confined within the arrays, how these are

Nelson A. Alves, Jeaneti P. N. Ferrite, Ulrich H. E. Hansmann

We compare two recently proposed methods for the characterization of phase transitions in small systems. The validity and usefulness of these approaches are studied for the case of the q=4 and q=5 Potts model, i.e. systems where a thermodynamic limit and exact results exist. Guided by this analysis we discuss then the helix-coil transition in polyalanine, an

Hari M. Gupta, Jose R. Campanha, Bianca A. Ferrari

Gradually Truncated Power law distribution - Citation of scientists Hari M. Gupta, Jose R. Campanha and Bianca A. Ferrari Unesp - Physics Dpto. - Rio Claro Sao Paulo - Brazil Abstract The number of times, a scientist is cited in other scientific publications is now an important factor in his merit consideration. Normally citation indices of highly cited scie

M. I. Alonso, K. Wakita, J. Pascual, M. Garriga

We report on the complex dielectric tensor components of four chalcopyrite semiconductors in the optical energy range (1.4-5.2 eV, from 0.9 eV for CuInSe2) determined at room temperature by spectroscopic ellipsometry. Our results were obtained on single crystals of CuInSe2, CuGaSe2, CuInS2, and CuGaS2. Values of refractive indices n, extinction coefficients

Bosiljka Tadic

Using numerical simulations and scaling theory we study the dynamics of the world-wide Web from the growth rules recently proposed in Ref. [1] with appropriate parameters. We demonstrate that the emergence of power-law behavior of the out- and in-degree distributions in the Web involves occurrence of temporal fractal structures, that are manifested in the sc

Attila Szolnoki, Gyorgy Szabo

Monte Carlo simulations and dynamical mean-field approximations are performed to study the phase transition in a driven lattice gas with nearest-neighbor exclusion on a square lattice. A slight extension of the microscopic dynamics with allowing the next-nearest-neighbor hops results in dramatic changes. Instead of the phase separation into high- and low-den

M. Jeng, A. W. W. Ludwig, T. Senthil, C. Chamon

We study how quasiparticle interactions affect their localization properties in dirty superconductors with broken time reversal symmetry -- for example in a magnetic field. For SU(2) spin-rotation invariant (class C) systems, the only important coupling is the spin-spin triplet interaction, which we study within a renormalization group approach. Either an ad

Simon Villain-Guillot, Christophe Josserand

We study the growth of a periodic pattern in one dimension for a model of spinodal decomposition, the Cahn-Hilliard equation. We particularly focus on the intermediate region, where the non-linearity cannot be negected anymore, and before the coalescence dominates. The dynamics is captured through the standard technique of a solubility condition performed ov

Brenda Frye, Tom Broadhurst, Narciso Benitez

We present discovery spectra of a sample of eight lensed galaxies at high redshift, 3.7<z<5.2, selected by their red colors in the fields of four massive clusters: A1689, A2219, A2390, and AC114. Metal absorption lines are detected and observed to be blueshifted by 300-800 km/s with respect to the centroid of Ly-alpha emission. A correlation is found between

J. A. Eisner, L. J. Greenhill, J. R. Herrnstein, J. M. Moran

We present the results of the first high angular resolution observations of SiO maser emission towards the star forming region W51-IRS2 made with the Very Large Array (VLA) and Very Long Baseline Array (VLBA). Our images of the water maser emission in W51-IRS2 reveal two maser complexes bracketing the SiO maser source. One of these water maser complexes appe

E. N. Dorband, Marc Hemsendorf, David Merritt

A systolic algorithm rhythmically computes and passes data through a network of processors. We investigate the performance of systolic algorithms for implementing the gravitational N-body problem on distributed-memory computers. Systolic algorithms minimize memory requirements by distributing the particles between processors. We show that the performance of

Mateusz Ruszkowski, Mitchell C. Begelman

The transfer of polarized radiation in stochastic synchrotron sources is explored by means of analytic treatment and Monte Carlo simulations. We argue that the main mechanism responsible for the circular polarization properties of compact synchrotron sources is likely to be Faraday conversion and that, contrary to common expectation, a significant rate of Fa

Greg L. Bryan, Tom Abel, Michael L. Norman

As an entry for the 2001 Gordon Bell Award in the &#34;special&#34; category, we describe our 3-d, hybrid, adaptive mesh refinement (AMR) code, Enzo, designed for high-resolution, multiphysics, cosmological structure formation simulations. Our parallel implementation places no limit on the depth or complexity of the adaptive grid hierarchy, allowing us to ac

Tom Abel, Greg L. Bryan, Michael L. Norman

We describe results from a fully self-consistent three dimensional hydrodynamical simulation of the formation of one of the first stars in the Universe. Dark matter dominated pre-galactic objects form because of gravitational instability from small initidal density perturbations. As they assemble via hierarchical merging, primordial gas cools through ro-vibr

Torsten Boeker, Seppo Laine, Roeland P. van der Marel, Marc Sarzi

We present new HST I-band images of a sample of 77 nearby, late-type spiral galaxies with low inclination. The main purpose of this catalog is to study the frequency and properties of nuclear star clusters. In 59 galaxies of our sample, we have identified a distinct, compact (but resolved), and dominant source at or very close to their photocenter. In many c

Y. Ulchin, O. Regev, G. A. Wynn

The structure of accretion discs around magnetic T Tauri stars is numerically calculated using a particle hydrodynamical code, in which magnetic interaction is included in the framework of King&#39;s diamagnetic blob accretion model. Setting up the calculation so as to simulate the density structure of a quasi-steady disc in the equatorial plane of a T Tauri

Hugh R. A. Jones, R. Paul Butler, C. G. Tinney, Geoffrey W. Marcy

We report the detection of a extrasolar planet candidate orbiting the G1 V star HD 39091. The orbital period is 2083 d and the eccentricity is 0.62. With a minimum (M sin $i$) mass of 10.3 M$_{\rm JUP}$ this object falls near the high mass end of the observed planet mass function, and may plausibly be a brown dwarf. Other characteristics of this system, incl

Anne Mathieu, Michael Merrifield, Konrad Kuijken

This paper investigates the detailed dynamical properties of a relatively homogeneous sample of disc-dominated S0 galaxies, with a view to understanding their formation, evolution and structure. By using high signal-to-noise ratio long-slit spectra of edge-on systems, we have been able to reconstruct the complete line-of-sight velocity distributions of stars

Stefan Harfst, Christian Theis, Gerhard Hensler

We present a new particle based code with a multi-phase description of the ISM implemented in order to follow the chemo-dynamical evolution of galaxies. The multi-phase ISM consists of clouds (sticky particles) and diffuse gas (SPH): Exchange of matter, energy and momentum is achieved by drag (due to ram pressure) and condensation or evaporation. Based on ti

A. Bosma

We still do not have a &#34;standard&#34; model for the mass distribution of spiral galaxies. I review various methods used to delimit the range of values of the mass-to-light ratio of the disk, such as spiral structure criteria, the influence of bars, warped and flaring HI layers, velocity dispersions, and features in the rotation curve occuring just beyond

Christian Theis

Most formation scenarios of globular clusters assume a molecular cloud as the progenitor of the stellar system. However, it is still unclear, how this cloud is transformed into a star cluster, i.e. how the destructive processes related to gas removal or low star formation efficiency can be avoided. Here a scheme of supernova (SN) induced cluster formation is

E. Athanassoula

In this paper I argue that, far from necessarily hindering bar formation in disc galaxies, inner haloes may stimulate it. This constitutes a new instability mechanism by which bars can grow. To show this I use a number of N-body simulations whose initial conditions have identical discs and more or less concentrated haloes. They show that the bar that grows i

E. Athanassoula

I present N-body simulations of isolated and interacting galaxies, made on GRAPE machines. In particular I discuss the formation and evolution of N-body bars and compare their properties to those of bars in early-type and late-type galactic discs. I argue that the halo can help the bar grow, contrary to previous beliefs, by taking positive angular momentum f

Min S. Yun, C. L. Carilli

As a logical next step in improving the radio-to-submm spectral index as a redshift indicator (Carilli & Yun 1999), we have investigated a technique of using the entire radio-to-FIR spectral energy distribution (SED) for deriving photometric redshifts for dusty starburst galaxies at high redshift. A dusty starburst SED template is developed from theoretical

K. Beuermann, K. Reinsch

We have investigated the nature of the magnetic white dwarf LP 790-29 = LHS 2293 by polarimetric monitoring, searching for short-term variability. No periodicity was found and we can exclude rotation periods between 4 sec and 1.5 hour with a high confidence. Maximum amplitudes of sinusoidal variations are Delta R < 0.009 mag and Delta V_R < 0.7% for a mean v

P. Sikivie

The late infall of cold dark matter onto an isolated galaxy, such as our own, produces streams and caustics in its halo. The outer caustics are topological spheres whereas the inner caustics are rings. The self-similar model of galactic halo formation predicts that the caustic ring radii $a_n$ follow the approximate law $a_n \sim 1/n$. In a study of 32 exten

V. Larionov, V. M. Lyuty, G. V. Zaitseva

A homogeneous set of UBV photometry (354 data points obtained between 1983 and 1998) for the Be/X-ray binary A0535+26 = V725Tau is analysed, aiming to look for possible periodic component(s). After subtraction of the long-term variation it was found that only a 103-day periodic component remains in the power spectra in both the V and B colour bands. The prob

Mordehai Milgrom

An account is given of the development, and the status, of the modified dynamics (MOND)--a proposed alternative to dark matter, which posits a breakdown of Newtonian dynamics in the limit of small accelerations.

I. Salamanca, R. J. Terlevich, G. Tenorio-Tagle

We report the detection of a very narrow P Cygni profile on top of the broad emission Ha and Hb lines of the Type IIn Supernova 1997eg. A similar feature has been detected in SN 1997ab (Salamanca et al. 1998), SN 1998S (Meikle & Geballe 1998, Fassia et al. 2001) and SN 1995G (Filippenko & Schlegel 1995). The detection of the narrow P Cygni profile indicates

I. Salamanca, L. Kaper, P. M. Vreeswijk, S. L. Ellison

Analysis of the absorption lines in the afterglow spectrum of the gamma-ray burst GRB010222 indicates that its host galaxy (at a redshift of z=1.476) is the strongest damped Lyman-alpha (DLA) system known, having a very low metallicity and modest dust content. This conclusion is based on the detection of the red wing of Lyman-alpha plus a comparison of the e

B. Famaey, H. Dejonghe

We present new tools to establish axisymmetric equilibrium models of the Milky Way. The models we wish to establish are pairs (V,F) where V is the gravitational potential generated by the whole mass distribution including the dark matter, and F is the distribution function in phase space for late-type tracer stars. We present a set of Stackel potentials that

G. Bono, A. Balbi, S. Cassisi, N. Vittorio

We present the results of a joint investigation aimed at constraining the primordial He content ($Y_P$) on the basis of both the Cosmic Microwave Background (CMB) anisotropy and two stellar observables, namely the tip of the Red Giant Branch (TRGB) and the luminosity of the Zero Age Horizontal Branch (ZAHB). Current baryon density estimates based on CMB meas

M. Stickel, U. Klaas, D. Lemke, K. Mattila

The ISOPHOT instrument aboard ISO has been used to observe extended FIR emission of six Abell clusters. The raw profiles of the I_(120 um) / I_(180 um) surface brightness ratio including zodiacal light show a bump towards Abell 1656 (Coma), dips towards Abell 262 and Abell 2670, and are without clear structure towards Abell 400, Abell 496, and Abell 4038. Af

Kevin A. Pimbblet

I discuss recent seminal work on the LARCS dataset: a panoramic study of rich clusters of galaxies at z~0.12. The importance of observing beyond the cluster core is illustrated by exploiting these data to examine colour gradients across the clusters.

Y. Hagiwara, P. J. Diamond, M. Miyoshi

We report the result of an on-going survey for 22 GHz H2O maser emission towards infrared luminous galaxies. The observed galaxies were selected primarily from the IRAS bright galaxy sample. The survey has resulted in the detection of one new maser. The new maser was discovered towards the [U]LIRG/merger galaxy NGC6240, which contains a LINER nucleus. This i

A. Heger, S. E. Woosley, I. Baraffe, T. Abel

While the modern stellar IMF shows a rapid decline with increasing mass, theoretical investigations suggest that very massive stars (>100 solar masses) may have been abundant in the early universe. Other calculations also indicate that, lacking metals, these same stars reach their late evolutionary stages without appreciable mass loss. After central helium b

Fridolin Weber

This paper discusses several most intruigung astrophysical implications connected with the possible absolute stability of strange quark matter.This is followed by a discussion of two astrophysical signals that may point at the existence of quark matter in both isolated neutron stars as well as in neutron stars in low-mass x-ray binaries (LMXBs).

M. S. Oey, B. Groves, L. Staveley-Smith, R. C. Smith

The ambient interstellar environment of wind- and supernova-driven superbubbles strongly affects their evolution, but its properties are rarely well-determined. We have therefore obtained HI aperture synthesis imaging of the environment around three similar, optically-selected superbubble nebulae in the Large Magellanic Cloud. The resulting HI maps show that

Peter Erwin, Juan Carlos Vega Beltran, John Beckman

We have found four barred S0 galaxies -- NGC 936, NGC 3945, NGC 4340, and NGC 4371 -- which contain smooth, luminous, purely stellar nuclear rings within their bars. These rings have little or no dust, no evidence for recent star formation, and are approximately the same color as surrounding bar and bulge. Thus, they are probably the aged remnants of bar-dri

Dean Richardson, David Branch, Darrin Casebeer, Jennifer Millard

The Asiago Supernova Catalog is used to carry out a comparative study of supernova absolute-magnitude distributions. An overview of the absolute magnitudes of the supernovae in the current observational sample is presented, and the evidence for subluminous and overluminous events is examined. The fraction of supernovae that are underluminous (M_B > -15) appe

E. V. Gotthelf, C. M. Olbert

We present preliminary results from a systematic spectral study of pulsars and their wind nebulae using the Chandra X-Ray Observatory. The superb spatial resolution of Chandra allows us to differentiate the compact object&#39;s spectrum from that of its surrounding nebulae. Specifically, for six Crab-like pulsars, we compare spectral fits of the averaged pul

Jeffrey D. P. Kenney, Elizabeth E. Yale

We present broadband and narrowband Hubble Space Telescope images of the central region of the heavily disturbed Virgo cluster galaxy NGC 4438 (Arp120), whose nucleus has been described as a type 1 LINER or dwarf Seyfert. Narrowband H-alpha and [NII] HST images reveal striking bipolar shell features, 1 kpc in projected length from end-to-end, which are likel

BRAHMS Collaboration, I. G. Bearden

We present charged particle densities as a function of pseudorapidity and collision centrality for the 197Au+197Au reaction at Sqrt{s_NN}=200 GeV. For the 5% most central events we obtain dN_ch/deta(eta=0) = 625 +/- 55 and N_ch(-4.7<= eta <= 4.7) = 4630+-370, i.e. 14% and 21% increases, respectively, relative to Sqrt{s_NN}=130 GeV collisions. Charged-particl

Benjamin McKay

We construct an explicit diffeomorphism taking any fibration of a sphere by great circles into the Hopf fibration, using elementary geometry--indeed the diffeomorphism is a local (differential) invariant, algebraic in derivatives.

Horace Stoica

The brane-world scenario offers the possibility for signals to travel outside our visible universe and reenter it. We find the condition for a signal emitted from the brane to return to the brane. We study the propagation of such signals and show that, as seen by a 4D observer, these signals arrive earlier than light traveling along the brane. We also study

G. Kofinas, E. Papantonopoulos, I. Pappa

An analysis of a spherically symmetric braneworld configuration is performed when the intrinsic curvature scalar is included in the bulk action; the vanishing of the electric part of the Weyl tensor is used as the boundary condition for the embedding of the brane in the bulk. All the solutions outside a static localized matter distribution are found; some of

L. E. Marcucci, R. Schiavilla, S. Rosati, A. Kievsky

The ^3He(mu^-,nu_mu)^3H weak capture is studied using correlated-hyperspherical-harmonics wave functions, obtained from realistic Hamiltonians consisting of the Argonne $v_{14}$ or Argonne $v_{18}$ two-nucleon, and Tucson-Melbourne or Urbana-IX three-nucleon interactions. The nuclear weak charge and current operators have vector and axial-vector components t

D. A. Sanders, L. M. Cremaldi, V. Eschenburg, C. N. Lawrence

The next generation of high-energy physics experiments is expected to gather prodigious amounts of data. New methods must be developed to handle this data and make analysis at universities possible. We examine some techniques that use recent developments in commodity hardware. We test redundant arrays of integrated drive electronics (IDE) disk drives for use