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astro-ph/9311049
Effects of Diurnal Modulation in Direct Cold Dark Matter Searches. the Experiment in Sierra Grande
Contains a summary, current status and prospects for the direct detection of cold dark matter using diurnal modulation effects as presented at the ELAF 93, Mar del Plata Argentina. The potential advantages of using the Earth as an absorber to produce diurnal modulation effects in cold dark matter searches are given alo...
1993-11-18
2007-05-23
[ "astro-ph" ]
D.E. Di Gregorio, A. Gattone, H. Huck, A.O. Macchiavelli, S. Gil, J. Collar and F.T. Avignone III
astro-ph/9311048
Cosmic ray ionization of the interstellar medium
We consider a cosmic ray spectrum that is a power law in momentum down to a cutoff and derive a lower cutoff corresponding to $E_{kin} \sim (30-60)$ MeV from the observed ionization rates in nearby diffuse clouds. While the real spectra of cosmic rays may not be so simple, we argue that one expects a substantial change...
1993-11-18
2015-06-24
[ "astro-ph" ]
Biman B. Nath and Peter L. Biermann
astro-ph/9311040
Microwave Anisotropies from Texture Seeded Structure Formation
The cosmic microwave anisotropies in a scenario of large scale structure formation with cold dark matter and texture are discussed and compared with recent observational results of the COBE satellite. A couple of important statistical parameters are determined. The fluctuations are slightly non gaussian. The quadrupole...
1993-11-17
2008-11-26
[ "astro-ph" ]
R.Durrer, A. Howard, Z.-H. Zhou
astro-ph/9311042
Dynamics of Clusters of Galaxies
The abundance and internal characteristics of rich clusters of galaxies can provide useful constraints on models of large--scale structure formation. This article will review some recent three dimensional, multi--fluid simulations of cluster dynamics and discuss their impact on issues raised from optical and X-ray obse...
1993-11-17
2007-05-23
[ "astro-ph" ]
August E. Evrard
astro-ph/9311039
Early Reionization in Cosmology
The cosmic microwave background (CMB) anisotropies have turned out to represent one of the most stringent 'bottle necks' for scenarios of large scale structure formation. As a possibility to relax this constraint, it has been proposed that early reionization can damp CMB fluctuations on small scales due to photon diffu...
1993-11-17
2009-10-22
[ "astro-ph" ]
Ruth Durrer
astro-ph/9311041
Gauge Invariant Cosmological Perturbation Theory
After an introduction to the problem of cosmological structure formation, we develop gauge invariant cosmological perturbation theory. We derive the first order perturbation equations of Einstein's equations and energy momentum ``conservation''. Furthermore, the perturbations of Liouville's equation for collisionless p...
1993-11-17
2010-12-09
[ "astro-ph" ]
Ruth Durrer
astro-ph/9311038
The Apm Galaxy Survey IV: Redshifts of Rich Clusters of Galaxies
We present redshifts for a sample of 229 clusters selected from the APM Galaxy Survey, 189 of which are new redshift determinations. Non-cluster galaxy redshifts have been rejected from this sample using a likelihood ratio test based on the projected and apparent magnitude distributions of the cluster fields. We test t...
1993-11-16
2015-06-24
[ "astro-ph" ]
G.B. Dalton (Oxford), G. Efstathiou (Oxford), S.J. Maddox (RGO), and W.J. Sutherland (Berkeley)
astro-ph/9311031
Modified-dynamics predictions agree with ovservations of the HI kinematics in faint dwarf galaxies contrary to the conclusions of Lo Sargent and Young
Lo, Sargent, and Young (1993) have recently concluded that the masses of some dwarf galaxies, as deduced by the modified dynamics (MOND) from the observed velocity dispersions, are systematically smaller than the observed masses, by a factor of ten or more. We show here that the MOND mass estimator used by Lo et al. is...
1993-11-15
2009-10-22
[ "astro-ph" ]
M. Milgrom
astro-ph/9311036
Pulsar Braking Index and Mass Accretion
I show that the braking index, $N$, a fundamental pulsar experimental quantity, naturally differs from the canonical value of 3 by terms which involve mass accretion. Using the measured values of $N$ for PSR1509-58 and PSR0531+21, I determine that for constant density neutron stars their present mass accretion rates ar...
1993-11-15
2007-05-23
[ "astro-ph" ]
P.D. Morley
astro-ph/9311034
The Stability of the Angular Two-Point Galaxy Correlation Function
In this paper, we investigate the effects of galactic extinction close to the south galactic pole and plate--to--plate matching errors. These represent the most probable systematic errors within the Edinburgh/Durham Southern Galaxy Catalogue (EDSGC) which could affect the angular correlation function. The distribution ...
1993-11-15
2007-05-23
[ "astro-ph" ]
Nichol & Collins
astro-ph/9311033
The Spatial Correlation Function from an X--ray Selected Sample of Abell Clusters
We present here the Spatial Two--Point Correlation Function for a complete sample of 67 X--ray selected Abell clusters of galaxies. We find a correlation length of $16.1\pm3.4\mpc$ with no significant clustering beyond $\simeq40\mpc$. This is the lowest uncorrected value for the correlation length ever derived from the...
1993-11-15
2015-06-24
[ "astro-ph" ]
Nichol, Briel & Henry
astro-ph/9311037
Non-Linear Axion Dynamics and Formation of Cosmological Pseudo-Solitons
The $(3+1)$-dimensional evolution of an inhomogeneous axion field configuration around the QCD epoch is studied numerically, including important non-linear effects due to the attractive self-interaction. It is found that axion perturbations on scales corresponding to causally disconnected regions at $T \sim 1 \, {\rm G...
1993-11-15
2011-07-19
[ "astro-ph", "gr-qc", "hep-ph" ]
Edward W. Kolb and Igor I. Tkachev
astro-ph/9311035
Gravitational Bending of Light with Frequency Shifts
Non-static gravitational fields generally introduce frequency shifts when bending light. In this paper, I discuss the frequency shifts induced in the bending of light by moving masses. As examples, I treat the recently discovered high-velocity pulsar PSR 2224+65 and a typical Einstein ring.
1993-11-15
2007-05-23
[ "astro-ph" ]
P.D. Morley
astro-ph/9311032
Morphology of the Interstellar Cooling Lines Detected by COBE
The FIRAS instrument on the COBE satellite has conducted an unbiased survey of the far-infrared emission from our Galaxy. The first results of this survey were reported by Wright et al. (1991). We report the results of new analyses of this spectral survey, which includes emission lines from 158 um C+, 122 um and 205 um...
1993-11-15
2012-08-27
[ "astro-ph" ]
C. L. Bennett, D. J. Fixsen, G. Hinshaw, J. C. Mather, S. H. Moseley, E. L. Wright, R. E. Eplee, Jr., J. Gales, T. Hewagama, R. B. Isaacman, R. A. Shafer & K. Turpie
astro-ph/9311029
Quantum Electrodynamics in the Gravitational Field of a Cosmic String
We evaluate the cross section for electron-positron pair production by a single high energy photon in the space-time of a static, straight cosmic string. Energy and momentum conservation precludes this process in empty Minkowski space. It happens around a cosmic string, in spite of the local flatness of the metric, as ...
1993-11-12
2009-10-22
[ "astro-ph", "gr-qc" ]
Vladimir Skarzhinsky, Diego Harari and Ulf Jasper
astro-ph/9311030
Limits on Three-Point Correlations in the COBE-DMR First Year Anisotropy Maps
We compute the three-point temperature correlation function of the {\it COBE} Differential Microwave Radiometer (DMR) first-year sky maps to search for non-Gaussian temperature fluctuations. The level of fluctuations seen in the computed correlation function are too large to be attributable solely to instrument noise. ...
1993-11-12
2009-10-22
[ "astro-ph" ]
G. Hinshaw, A. Kogut, K.M. Gorski, A.J. Banday, C.L. Bennett, C. Lineweaver, P. Lubin, G.F. Smoot & E.L. Wright
astro-ph/9311028
Evolution of One-Point Distributions from Gaussian Initial Fluctuations
We study the quasilinear evolution of the one-point probability density functions (PDFs) of the smoothed density and velocity fields in a cosmological gravitating system beginning with Gaussian initial fluctuations. Our analytic results are based on the Zel'dovich approximation and laminar flow. A numerical analysis ex...
1993-11-11
2009-10-22
[ "astro-ph" ]
Lev Kofman (IFA, U of Hawaii, and CITA), Edmund Bertschinger (MIT), James M. Gelb (MIT), Adi Nusser (CPA, Berkeley) and Avishai Dekel (Hebrew University)
astro-ph/9311027
Cosmological Distribution Functions
The evolution of probability distribution functions (PDFs) of continuous density, velocity and velocity derivatives ( deformation tensor) fields in the theory of cosmological gravitational instability are considered. We show that in the Newtonian theory the dynamical equations cannot be reduced to the closed set of Lag...
1993-11-11
2007-05-23
[ "astro-ph" ]
Lev Kofman (Institute for Astronomy, University of Hawaii)
astro-ph/9311026
The X-Ray Background: Observations
Invited review talk given at the Meeting on "Extragalactic Background Radiation: A meeting in honor of Riccardo Giacconi" Baltimore, May 18-20, 1993 Ro be published by Cambridge University Press
1993-11-11
2007-05-23
[ "astro-ph" ]
Giovanni Zamorani
astro-ph/9311025
On the Galactic Distribution of Gamma Ray Bursts
Quashnock and Lamb (1993) defined a sub-sample of Gamma-ray Bursts (GRBs) from the publicly available BATSE database which shows clumping toward the galactic plane, and concluded that all GRBs are galactic in origin. The selection of these bursts (duplicated in this work in Sample 1) involved a peak countrate (in count...
1993-11-11
2016-06-08
[ "astro-ph" ]
Robert E. Rutledge, Walter H.G. Lewin
astro-ph/9311023
Quasi-Linear Evolution of Compensated Cosmological Perturbations: The Nonlinear Sigma Model
We consider the evolution of perturbations to a flat FRW universe that arise from a ``stiff source,'' such as a self-ordering cosmic field that forms in a global symmetry-breaking phase transition and evolves via the Kibble mechanism. Although the linear response of the normal matter to the source depends on the detail...
1993-11-09
2009-10-22
[ "astro-ph", "hep-ph" ]
Andrew H. Jaffe
astro-ph/9311022
Ultraviolet Radiation from Evolved Stellar Populations -- I. Models
This series of papers comprises a systematic exploration of the hypothesis that the far ultraviolet radiation from star clusters and elliptical galaxies originates from extremely hot horizontal-branch (HB) stars and their post-HB progeny. This first paper presents an extensive grid of calculations of stellar models fro...
1993-11-09
2009-10-22
[ "astro-ph" ]
B. Dorman, R. Rood, and R. O'Connell
astro-ph/9311021
A toolbox for general elliptical gravitational lenses
We introduce a formalism to describe 2D-Potentials for 2D-matter (or charge) distributions with arbitrary elliptical symmetry including varying eccentricity and twisting of the iso-density curves. We use this approach to describe elliptical matter distributions such as elliptical galaxies or clusters as gravitational l...
1993-11-09
2007-05-23
[ "astro-ph" ]
T. Schramm
astro-ph/9311024
Polarization of the Microwave Background in Inflationary Cosmology
We evaluate the large scale polarization of the cosmic microwave background induced, via Thomson scattering prior to decoupling, by nearly scale-invariant spectra of scalar and tensor metric perturbations, such as those predicted by most inflationary models of the early Universe. We solve the radiative transfer equatio...
1993-11-09
2016-08-30
[ "astro-ph", "gr-qc" ]
Diego Harari and Matias Zaldarriaga (Univ. of Buenos Aires)
astro-ph/9311020
Mapping Moderate Redshift Cluster
To test whether clusters have rising mass to light ratios at large radii and to estimate the amplitude of the density fluctuation spectrum on the scale of 10\hmpc\ the Canadian Network for Observational Cosmology (CNOC) cluster collaboration is obtaining Multi-Object Spectrograph velocities and two colour photometry fo...
1993-11-07
2007-05-23
[ "astro-ph" ]
Carlberg, et al
astro-ph/9311018
Non-Linear Clustering in the Cold+Hot Dark Matter Model
We use high resolution PM N-body simulations to follow the development of non-linear clustering in a flat Universe, dominated by Cold + Hot Dark Matter (CHDM) with 60% of CDM, 30% of HDM and 10% of baryons; a simulation box of 100 Mpc a side ($h=0.5$) is used. We analyze two CHDM simulations with $b =1.5$ (COBE normali...
1993-11-06
2015-06-24
[ "astro-ph" ]
S.A. Bonometto, S. Borgani, S. Ghigna, A. Klypin, J.R. Primack
astro-ph/9311019
Convergence properties of finite-difference hydrodynamics schemes in the presence of shocks
We investigate asymptotic convergence in the~$\Delta x \!\rightarrow\! 0$ limit as a tool for determining whether numerical computations involving shocks are accurate. We use one-dimensional operator-split finite-difference schemes for hydrodynamics with a von Neumann artificial viscosity. An internal-energy scheme con...
1993-11-06
2009-09-25
[ "astro-ph" ]
Paul A. Kimoto & David F. Chernoff
astro-ph/9311017
Global String Radiation
We study Goldstone boson (or axion) radiation from global $U(1)$-strings making direct quantitative comparisons between numerical scalar field theory simulations and linearized analytic calculations in the dual antisymmetric tensor representation. Concentrating on periodic long string configurations, we show excellent ...
1993-11-05
2009-10-22
[ "astro-ph", "cond-mat", "hep-ph", "hep-th" ]
R.A.Battye and E.P.S.Shellard
astro-ph/9311016
Molecular Lines in Bok Globules and Around Herbig Ae/be Stars
This paper is intended as part of a more extensive molecular line survey in star forming regions along the evolutionary track of a collapsing cloud toward a young stellar object. We have studied a sample of seven small dark clouds (Bok globules) and eight Herbig Ae/Be stars in the J=1->0 transition of HCO$^{+}$, H$^{13...
1993-11-05
2009-10-22
[ "astro-ph" ]
F. Scappini, G.G.C. Palumbo, G. Bruni and P. Bergman
astro-ph/9311015
Radio and Optical Emission, Spectral Shapes and Breaks in GRB
Relativistic blast wave models predict the spectrum of the emitted synchrotron radiation. The electrons in the shocked region are heated to a Wien distribution whose ``temperature'' is $1/3$ of the mean electron energy. This energy scale determines a characteristic (break) frequency of synchrotron radiation. At much lo...
1993-11-03
2015-06-24
[ "astro-ph" ]
J. I. Katz
astro-ph/9311014
Reconstruction of the Large Scale Structure
The large scale structure of the universe is reconstructed by means of the Wiener filter and constrained realizations of Gaussian fields. The density field constructed from optically selected galaxies (Hudson \cite{Hudson}) has been sampled out to a distance of $80\hmpc$. This data set is used for the reconstruction of...
1993-11-03
2007-05-23
[ "astro-ph" ]
Y. Hoffman
astro-ph/9311013
Clustering in Redshift Space: Linear Theory
The clustering in redshift space is studied here to first order within the framework of gravitational instability. The distortion introduced by the peculiar velocities of galaxies results in anisotropy in the galaxy distribution and mode-mode coupling when analyzed in Fourier space. An exact linear calculation of the f...
1993-11-03
2008-02-03
[ "astro-ph" ]
Saleem Zaroubi and Yehuda Hoffman
astro-ph/9311008
Large-scale correlations between QSOs and IRAS galaxies
We demonstrate that high-redshift 1-Jansky radio sources are correlated with foreground IRAS galaxies on angular scales of several 10 arc minutes on a statistical significance level of up to 99.8\%. Based on a theoretical analysis published earlier, we propose to interpret these correlations in terms of gravitational l...
1993-11-02
2007-05-23
[ "astro-ph" ]
M. Bartelmann and P. Schneider
astro-ph/9311012
Microwave Background Anisotropies in Primeval Isocurvature Baryon Models: Constraints on the Cosmological Parameters
We have performed the most comprehensive predictions of the temperature fluctuations \dtt in the primeval isocurvature baryon models to see whether or not the models are consistent with the recent data on the cosmic microwave background anisotropies. More specifically, we computed the \dtt corresponding to the experime...
1993-11-02
2009-10-22
[ "astro-ph" ]
Takashi Chiba, Naoshi Sugiyama and Yasushi Suto
astro-ph/9311011
A gravitational lens model for B1422+231
We construct a simple elliptical gravitational lens model for the quadruple lens B1422+231 and show that the details of the configuration cannot be easily understood in terms of this model; in particular, the flux ratios of the images are hard to reproduce. This qualitatively verifies the results from a different lens ...
1993-11-02
2007-05-23
[ "astro-ph" ]
R. Kormann, P. Schneider and M. Bartelmann
astro-ph/9311009
Magnetic Activity in Thick Accretion Disks and Associated Observable Phenomena: II. Flux Storage
In paper I, we have studied the conditions under which flux tubes are expelled from adiabatic thick accretion disks. In the present paper, we explore a few other models of thick disks, where flux tubes could be stored. We show that flux tubes with sufficiently weak fields are not expelled out if they move adiabatically...
1993-11-02
2009-10-22
[ "astro-ph" ]
Sydney D'Silva and Sandip K. Chakrabarti
astro-ph/9311010
Magnetic Activity in Thick Accretion Disks and Associated Observable Phenomena I. Flux Expulsion
We study the dynamics of toroidal magnetic flux tubes, symmetric about the rotation axis, inside non-magnetic thick accretion disks around black holes. We present model equations which include effects of gravity, centrifugal force, pressure gradient force, Coriolis force, drag, magnetic tension and magnetic buoyancy. W...
1993-11-02
2009-10-22
[ "astro-ph" ]
Sandip K. Chakrabarti and Sydney D'Silva
astro-ph/9311003
Structural Characteristics and Stellar Composition of Low Surface Brightness Disk Galaxies
We present UBVI surface photometry of a sample of low surface brightness (LSB) disk galaxies. LSB disk galaxies are fairly well described as exponential disks with no preferred value for either scale length, central surface brightness, or rotational velocity. Indeed, the distribution of scale lengths is indistinguishab...
1993-11-01
2009-10-22
[ "astro-ph" ]
Stacy McGaugh & Greg Bothun
astro-ph/9311007
The X-ray Behavior of Two CVs: TT Ari and DP Leo
We present ROSAT PSPC observations of the nova-like, or intermediate polar, TT Ari and the eclipsing polar DP Leo. Observations of TT Ari were performed as part of a simultaneous multiwavelength campaign. The X-ray spectrum of TT Ari from ROSAT was combined with Ginga observations to suggest the presence of three disti...
1993-11-01
2007-05-23
[ "astro-ph" ]
Craig R. Robinson and France A. Cordova
astro-ph/9311001
Monitoring of active galactic nuclei. V. The Seyfert 1 galaxy Markarian 279
We report on the Lovers of Active Galaxies' (LAG) monitoring of the Seyfert 1 galaxy Markarian 279 from January to June 1990. The source, which was in a very bright state, gradually weakened after the first month of monitoring: the H-Alpha and H-Beta flux decreased by 20% and 35% respectively, and the continuum under H...
1993-11-01
2007-05-23
[ "astro-ph" ]
G.M. Stirpe, et al
astro-ph/9311005
Colors and color gradients in bulges of galaxies
We have obtained surface photometry in U, B, R and I for a complete optically selected sample of 45 early-type spiral galaxies, to investigate the colors and color gradients of spiral bulges. Color profiles in U-R, B-R, U-B and R-I have been determined in wedges opening on the minor axes. Based on several criteria, we ...
1993-11-01
2009-09-25
[ "astro-ph" ]
M. Balcells and R.F. Peletier
astro-ph/9311002
Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. VI. Variability of NGC 3783 from ground-based data
The Seyfert 1 galaxy NGC 3783 was intensely monitored between 1991 December and 1992 August. We present the results from the ground-based observations in the optical and near-IR, which complement the data-set from the IUE, discussed elsewhere. Spectroscopic and photometric data from many observatories were combined in ...
1993-11-01
2009-10-22
[ "astro-ph" ]
G.M. Stirpe, et al
astro-ph/9311004
Spatial Distribution of Low Surface Brightness Galaxies
Using redshift samples, we calculate the cross-correlation functions of LSB galaxies with normal galaxies in complete samples (i.e. CfA and IRAS), which enables us to compare directly the amplitudes and shapes of the correlation functions. For pair separations $r\gs 2\mpc$, we find that the shape is in agreement with t...
1993-11-01
2015-06-24
[ "astro-ph" ]
H.J. Mo, S.S. McGaugh, & G.D. Bothun
astro-ph/9311006
Primordial Nucleosynthesis in Conformal Weyl Gravity
Recently conformal Weyl gravity has been considered as a candidate alternative gravity theory. This fourth-order theory is attractive because it is the only metric theory of gravity which is invariant under local conformal transformations of the metric. We calculate the primordial light element abundances in this theor...
1993-11-01
2009-09-25
[ "astro-ph", "gr-qc" ]
Lloyd Knox and Arthur Kosowsky (University of Chicago)
astro-ph/9310051
Reionization and Cosmic Microwave Anisotropies
The effects of reionization, occurring after standard recombination in cold dark matter-dominated models, on CMB anisotropies are investigated. Late-time reionization reduces the CMB anisotropies, in particular, on degree scales. It is found that constraints on cold dark matter-dominated models from the highest frequen...
1993-10-29
2009-10-22
[ "astro-ph" ]
Naoshi Sugiyama, Joseph Silk and Nicola Vittorio
astro-ph/9310052
Models for the Evolution of the Spectral Energy Distribution of Elliptical Galaxies from UV to Far--IR Wavelengths
We have worked out evolutionary synthesis models of the broad-band spectral energy distribution of elliptical galaxies over the whole frequency range from UV to far--IR. Internal extinction and far--IR re--emission by interstellar dust have been taken into account in a self--consistent way. Diffuse dust emission has be...
1993-10-29
2009-10-22
[ "astro-ph" ]
P. Mazzei, G. De Zotti, C. Xu
astro-ph/9310048
Analysis of Small Scale MBR Anisotropy in the Presence of Foreground Contamination
Many of the current round of experiments searching for anisotropies in the MBR are confronting the problem of how to disentangle the cosmic signal from contamination due to galactic and intergalactic foreground sources. Here we show how commonly used likelihood function techniques can be generalized to account for fore...
1993-10-28
2009-10-22
[ "astro-ph" ]
Scott Dodelson and Albert Stebbins
astro-ph/9310049
Bulge/Disk Segregation in the Universe
The observations of bulge/disk segregation in the Universe are reviewed with a focus on whether the observed segregation in clusters is local or global, and whether there is bulge-disk segregation on large-scales. The high concentration of bulge-rich galaxies in the cores of clusters of galaxies can be accounted for by...
1993-10-28
2007-05-23
[ "astro-ph" ]
Gary A. Mamon
astro-ph/9310050
Modes of Elliptical Galaxies
Long lived modes of elliptical galaxies can exist {\it \`a la} van Kampen. Specific systems may possess long lived oscillations which Landau damp on time scales longer than a Hubble time. Some physical processes such as a close encounter, tidal forces from a cluster or an orbiting satellite could preferentially excite ...
1993-10-28
2009-10-22
[ "astro-ph" ]
Ue-Li Pen
astro-ph/9310047
Simulation of Thick Accretion Disks with Standing Shocks by Smoothed Particle Hydrodynamics
We present results of numerical simulation of inviscid thick accretion disks and wind flows around black holes. We use Smoothed Particle Hydrodynamics (SPH) technique for this purpose. Formation of thick disks are found to be preceded by shock waves travelling away from the centrifugal barrier. For a large range of the...
1993-10-27
2009-10-22
[ "astro-ph" ]
Diego Molteni, G. Lanzafame and S. K. Chakrabarti
astro-ph/9310045
Gravitational Waves and the Polarisation of the Cosmic Microwave Background
We discuss the influence of gravitational waves (GWs) upon the polarisation of the Cosmic Microwave Background Radiation (CMBR). We show how to compute the {\em rms} temperature anisotropy and polarisation of the CMBR induced by GWs of arbitrary wavelength. We find that the ratio of polarisation, $\Pi$, to anisotropy, ...
1993-10-26
2016-06-08
[ "astro-ph" ]
R. A. Frewin, A. G. Polnarev and P. Coles
astro-ph/9310046
The Small Scale Integrated Sachs-Wolfe Effect
The integrated Sachs-Wolfe effect (ISW) can be an important factor in the generation of Cosmic Microwave Background anisotropies on all scales, especially in a reionized curvature or lambda dominated universe. We present an analytic treatment of the ISW effect, which is analogous to thick last scattering surface techni...
1993-10-26
2009-07-17
[ "astro-ph" ]
Wayne Hu and Naoshi Sugiyama
astro-ph/9310044
Gravitational Radiation from First-Order Phase Transitions
We consider the stochastic background of gravity waves produced by first-order cosmological phase transitions from two types of sources: colliding bubbles and hydrodynamic turbulence. First we discuss the fluid mechanics of relativistic spherical combustion. We then numerically collide many bubbles expanding at a veloc...
1993-10-25
2009-10-22
[ "astro-ph", "gr-qc", "hep-ph" ]
Marc Kamionkowski, Arthur Kosowsky, and Michael S. Turner
astro-ph/9310043
Weighted Bias and Galaxy Clustering
We consider a weighted biasing scheme for galaxy clustering. This differs from previous treatments in the fact that the biased density field coincides with the background mass--density whenever the latter exceeds a given threshold value. There is some physical motivation for this scheme and it is in better accord with ...
1993-10-25
2015-06-24
[ "astro-ph" ]
P. Catelan, P. Coles, S. Matarrese and L. Moscardini
astro-ph/9310042
Smoothed Particle Hydrodynamics Confronts Theory: Formation of Standing Shocks in Accretion Disks and Winds Around Black Holes
We present results of numerical simulation of thin accretion disks and winds. We use the Smoothed Particle Hydrodynamics (SPH) technique for this purpose. We show that the simulation agrees very well with the recent theoretical work on the shock formation. The most significant conclusion is that shocks in an inviscid f...
1993-10-25
2009-10-22
[ "astro-ph" ]
Sandip K. Chakrabarti and Diego Molteni
astro-ph/9310041
Topological Defects and Structure Formation
Topological defects are produced during phase transitions in the very early Universe. They arise in most unified theories of strong, weak and electromagnetic interactions. These lectures focus on the role of topological defects in cosmology, with particular emphasis on the models of structure formation based on defects...
1993-10-24
2010-11-01
[ "astro-ph", "hep-ph" ]
Robert H. Brandenberger (Brown University)
astro-ph/9310040
How Unusual is the Locally Quiet Hubble Flow?
The local galaxy distribution offers an interesting constraint to cosmological models of structure formation. The galaxies are distributed in a long, filamentary structure, presumably the result of large amplitude gravitational instability, yet the local velocity field is cold. In particular, there are no blueshifted g...
1993-10-22
2009-10-22
[ "astro-ph" ]
David Schlegel, Marc Davis, Frank Summers and Jon A. Holtzman
astro-ph/9310039
Statistical Tests for the Gaussian Nature of Primordial Fluctuations Through CBR Experiments
Information about the physical processes that generate the primordial fluctuations in the early universe can be gained by testing the Gaussian nature of the fluctuations through cosmic microwave background radiation (CBR) temperature anisotropy experiments. One of the crucial aspects of density perturbations that are p...
1993-10-21
2009-12-30
[ "astro-ph" ]
Xiaochun Luo
astro-ph/9310038
On Nonlinear Approximations to Cosmic Problems with Mixed Boundary Conditions
Nonlinear approximations to problems with mixed boundary conditions are useful for predicting large-scale streaming velocities from the density field, or vice-versa. We evaluate the schemes of Bernardeau \cite{bernardeau92}, Gramann \cite{gramann93}, and Nusser \etal \cite{nusser91}, using smoothed density and velocity...
1993-10-20
2007-05-23
[ "astro-ph" ]
Paul J. Mancinelli, Amos Yahil, Galit Ganon, and Avishai Dekel
astro-ph/9310037
Filling Factors and Ionized Masses in Planetary Nebulae
We calculate filling factors (${\varepsilon}$) and ionized masses (M$_{\rm i}$) for a total of 84 galactic and extragalactic planetary nebulae (PNe) at known distances. To do these calculations, we have chosen forbidden line electron densities, observed angular diameters, and H${\beta}$ fluxes, from the most recent mea...
1993-10-19
2007-05-23
[ "astro-ph" ]
F. R. Boffi and L. Stanghellini
astro-ph/9310036
General Relativistic Dynamics of Irrotational Dust: Cosmological Implications
The non--linear dynamics of cosmological perturbations of an irrotational collisionless fluid is analyzed within General Relativity. Relativistic and Newtonian solutions are compared, stressing the different role of boundary conditions in the two theories. Cosmological implications of relativistic effects, already pres...
1993-10-18
2009-10-22
[ "astro-ph" ]
Sabino Matarrese, Ornella Pantano and Diego Saez
astro-ph/9310035
A New Method for Estimating the Distance to Young Open Clusters
We present a new technique for estimating the distance to young open clusters. The method requires accurate measurement of the axial rotation period of late-type members of the cluster: rotation periods are first combined with projected rotation velocities and an estimate of the angular diameter for each star -- obtain...
1993-10-15
2015-06-24
[ "astro-ph" ]
Martin A. Hendry, Mark A. O'Dell and Andrew Collier-Cameron (University of Sussex, Brighton BN1 9QH.)
astro-ph/9310027
Properties of $^{8}$Be and $^{12}$C deduced from the folding--potential model
The $\alpha$--$\alpha$ differential cross sections are analyzed in the optical model using a double--folded potential. With the knowledge of this potential bound and resonance--state properties of $\alpha$--cluster states in $^{8}$Be and $^{12}$C as well as astrophysical S--factors of $^{4}$He($\alpha$,$\gamma$)$^{8}$B...
1993-10-14
2015-06-24
[ "astro-ph" ]
P. Mohr, H. Abele, V. K\"olle, G. Staudt, H. Oberhummer, H. Krauss
astro-ph/9310032
Cosmic-Ray Antiprotons from Neutralino Annihilation into Gluons
We estimate the flux of cosmic-ray antiprotons expected from the annihilation of neutralinos in the galactic halo. The antiproton signal may offer an important alternative detection scheme in the case that neutralino annihilation proceeds mainly to the two-gluon final state.
1993-10-14
2010-11-30
[ "astro-ph", "hep-ph" ]
Gerard Jungman and Marc Kamionkowski
astro-ph/9310028
What Do We Mean by Malmquist Bias?
In this paper we review the two main approaches to the problem of Malmquist bias which have been adopted in the cosmology literature, and show how these two formulations of the problem represent fundamentally different views of the nature of probability. We discuss the assumptions upon which both approaches are based a...
1993-10-14
2007-05-23
[ "astro-ph" ]
Martin A. Hendry, John F. L. Simmons, Andrew M. Newsam
astro-ph/9310030
HST Observations of Globular Clusters in M31.I:Surface Photometry of 13 Objects
We present the initial results of a study of globular clusters in M31, using the Faint Object Camera (FOC) on the Hubble Space Telescope (HST). The sample of objects consists of 13 clusters spanning a range of properties. Three inde- pendent image deconvolution techniques were used in order to compensate for the optica...
1993-10-14
2007-05-23
[ "astro-ph" ]
F. Fusi Pecci, P. Battistini, O. Bendinelli, F. B\`onoli, C. Cacciari, S. Djorgovski, L. Federici, F.R. Ferraro, G. Parmeggiani, N. Weir, F. Zavatti
astro-ph/9310029
Optimal Galaxy Distance Estimators
The statistical properties of galaxy distance estimators are studied and a rigorous framework is developed for identifying and removing the effects of Malmquist bias due to obsevational selection. The prescription of Schechter (1980) for defining unbiased distance estimators is extended to more general -- and more real...
1993-10-14
2009-10-22
[ "astro-ph" ]
Martin A. Hendry, John F. L. Simmons
astro-ph/9310031
Optimal Addition of Images for Detection and Photometry
In this paper we describe weighting techniques used for the optimal coaddition of CCD frames with differing characteristics. Optimal means maximum signal-to-noise (s/n) for stellar objects. We derive formulae for four applications: 1) object detection via matched filter, 2) object detection identical to DAOFIND, 3) ape...
1993-10-14
2009-10-22
[ "astro-ph" ]
Philippe Fischer, Greg P. Kochanski
astro-ph/9310033
New Distance Measurements to the $\alpha$ Persei and Pleiades Clusters
We apply the new distance measuring technique of Hendry, O'Dell and Collier- Cameron, 1993, to the Pleiades and $\alpha$ Persei clusters. The method relies on knowledge of the periods, rotation velocities and angular diameters of a sample of late-type stars within each cluster. The angular diameters were found by recal...
1993-10-14
2015-06-24
[ "astro-ph" ]
Mark A. O'Dell, Martin A. Hendry, Andrew Collier Cameron
astro-ph/9310034
Study of the Core of the Shapley Concentration: I.the Sample
We report the first results of a spectroscopic survey of galaxies in the core of the Shapley Concentration, the richest nearby supercluster of clusters of galaxies. We have measured 311 new galaxy redshifts in an area of $\sim 4.5$ square degrees centered around the Abell cluster A3558. Considering also the data alread...
1993-10-14
2015-06-24
[ "astro-ph" ]
S. Bardelli, E.Zucca, G.Vettolani, G.Zamorani, et al
astro-ph/9310026
Alpha Clustering and the stellar nucleosynthesis of carbon
The astrophysical S--factor and reaction rates for the triple--alpha process are calculated in the direct--capture model. It is shown that the stellar carbon production is extremely sensitive to small variations in the N--N interaction.
1993-10-14
2015-06-24
[ "astro-ph" ]
H. Oberhummer, H. Krauss, K. Gr\"un, T. Rauscher, H. Abele, P. Mohr, G. Staudt
astro-ph/9310023
Mergers of Systems Containing Gas
Several simple mergers between model galaxy clusters containing a mixture of gas and dark matter are examined, testing the coupling of the gas to the underlying collisionless material. The gas is shocked, irreversibly dissipating the energy fed into it by the collisionless component and forms a resolved constant-densit...
1993-10-13
2015-06-24
[ "astro-ph" ]
F.R.Pearce, P.A.Thomas, H.M.P.Couchman
astro-ph/9310024
An Owner's Guide to Smoothed Particle Hydrodynamics
We present a practical guide to Smoothed Particle Hydrodynamics (\SPH) and its application to astrophysical problems. Although remarkably robust, \SPH\ must be used with care if the results are to be meaningful since the accuracy of \SPH\ is sensitive to the arrangement of the particles and the form of the smoothing ke...
1993-10-13
2007-05-23
[ "astro-ph" ]
T.J.Martin, F.R.Pearce, P.A.Thomas
astro-ph/9310022
Third-Order Lagrangian Perturbation Theory - Realization at High-Spatial Resolution
The Lagrangian theory of gravitational instability of homogeneous-isotropic Friedman-Lemaitre cosmogonies investigated and solved in the series of papers by Buchert (1989), (1992), Buchert & Ehlers (1993), Buchert (1993a,b), Ehlers & Buchert (1993), is illustrated. The third-order solution of this theory for generic in...
1993-10-13
2007-05-23
[ "astro-ph" ]
T. Buchert, A. G. Weiss
astro-ph/9310025
A Simple Model of Large Scale Structure Formation
We explore constraints on inflationary models employing data on large scale structure mainly from COBE temperature anisotropies and IRAS selected galaxy surveys, taking care not to apply linear perturbation theory to data in the non-linear regime. In models where the tensor contribution to the COBE signal is negligible...
1993-10-13
2009-12-30
[ "astro-ph", "hep-ph" ]
R.K. Schaefer and Q. Shafi
astro-ph/9310021
On the Galactic Evolution of $D$ and $^3He$
The determined abundances of primordial $^4He$ and $^7Li$ provide a basis with which to test the standard model of big bang nucleosynthesis in conjunction with the other two light element isotopes $D$ and $^3He$, also produced in the big bang. Overall, consistency in the standard big bang nucleosynthesis model is best ...
1993-10-12
2009-10-22
[ "astro-ph" ]
Elisabeth Vangioni-Flam, Keith A. Olive, and Nikos Prantzos
astro-ph/9310020
The Nuclear Ten Micron Emission of Spiral Galaxies
We examine the 10\m\ emission of the central regions of 281 spiral galaxies, after having compiled all ground-based, small-aperture ($\sim$5") broad-band photometric observations at \l$\sim$10\m\ (N magnitudes) published in the literature. We evaluate the compactness of the $\sim$10\m\ emission of galaxy nuclei by comp...
1993-10-12
2009-10-22
[ "astro-ph" ]
G. Giuricin, L. Tamburini, F. Mardirossian, M. Mezzetti, P. Monaco
astro-ph/9310019
The Meaning of Eros/Macho
Most of the mass density in the Universe---and in the halo of our own galaxy---exists in the form of dark matter. Overall, the contribution of luminous matter (in stars) to the mass density of the Universe is less than 1\%; primordial nucleosynthesis indicates that baryons contribute between 1\% and 10\% of the critica...
1993-10-12
2009-09-25
[ "astro-ph", "hep-ph" ]
Michael S. Turner (Fermilab/U. Chicago)
astro-ph/9310018
Non--Linear Dynamics of Irrotational Dust: Eulerian and Lagrangian Approaches
Some recently proposed approximations to follow the non--linear evolution of collisionless matter perturbations in the universe are reviewed. The first one, called frozen--flow approximation, is an Eulerian method within Newtonian theory, and is based on neglecting the role of particle inertia compared to the damping i...
1993-10-11
2007-05-23
[ "astro-ph" ]
S. Matarrese, P. Catelan, F. Lucchin, L. Moscardini, O. Pantano and D. Saez
astro-ph/9310017
The Correlation Function of Rich Clusters of Galaxies in CDM-like Models
We use ensembles of high-resolution CDM simulations to investigate the shape and amplitude of the two point correlation function of rich clusters. The standard scale-invariant CDM model with $\Omega=1$ provides a poor description of the clustering measured from the APM rich cluster redshift survey, which is better fitt...
1993-10-11
2015-06-24
[ "astro-ph" ]
R. A. C. Croft and G. Efstathiou
astro-ph/9310016
Large-scale structure and motions from simulated galaxy clusters
We use high resolution dissipationless N-body simulations to examine the spatial distribution of galaxy clusters on large scales. The Standard CDM model and two of its main competitors, Low density CDM and Mixed Dark Matter are compared.The two-point correlation function of simulated clusters is compared with an extend...
1993-10-11
2007-05-23
[ "astro-ph" ]
R. A. C. Croft and G. Efstathiou
astro-ph/9310015
Baryonic Content of Galactic Halos and Constraints on Models for Structure Formation
The recent detection of microlensing of stars of LMC by compact objects in the halo of our galaxy suggests that our galaxy is surrounded by a non-luminous halo made of compact objects with mass of about $(0.03-0.5) \msun$. The rate of detection could be consistent with the assumption that these halo objects are distrib...
1993-10-07
2007-05-23
[ "astro-ph" ]
T.Padmanabhan and K.Subramanian
astro-ph/9310012
Natural Inflation
A pseudo-Nambu-Goldstone boson, with a potential of the form $ V(\phi) = \Lambda^4 [1 + \cos(\phi/f)]$, can naturally give rise to an epoch of inflation in the early universe (Freese, Frieman, and Olinto 1990). The potential is naturally flat (as required by microwave background limits on the amplitude of density fluct...
1993-10-06
2007-05-23
[ "astro-ph" ]
Katherine Freese
astro-ph/9310013
General Analytic Results for Nonlinear Waves and Solitons in Molecular Clouds
We study nonlinear wave phenomena in self-gravitating fluid systems, with a particular emphasis on applications to molecular clouds. This paper presents analytical results for one spatial dimension. We show that a large class of physical systems can be described by theories with a ``charge density'' $q(\rho)$; this qua...
1993-10-06
2009-10-22
[ "astro-ph" ]
Fred C. Adams, Marco Fatuzzo, and Richard Watkins
astro-ph/9310014
Subclustering and Luminous-Dark Matter Segregation in Galaxy Clusters
We have performed a series of N-body experiments on Connection Machine-5 in order to simulate the formation of galaxy clusters gravitationally dominated by a massive dark background. In accordance with previous authors we find an extremely inhomogeneous evolution where subcondensations are continually formed and merged...
1993-10-06
2009-10-22
[ "astro-ph" ]
A. Serna, J.M. Alimi and H. Scholl
astro-ph/9310010
Self-Gravity and Dissipation in Polar Rings
We construct models of highly-inclined (``polar'') rings in an external potential including both self--gravity and dissipation due to a drag force. We adopt the oblate spheroidal scale--free logarithmic potential with axis ratio $q=0.85$ and an initial inclination of 80$^\circ$ for the self--gravitating rings. Stellar ...
1993-10-05
2009-10-22
[ "astro-ph" ]
John Dubinski and Dimitris Christodoulou
astro-ph/9310011
Lowered Evans Models: Analytic Distribution Functions of Oblate Halo Potentials
We describe an analytic distribution function of a finite, oblate stellar system that is useful for the practical modelling of dark halos. The function is determined by lowering Evans's (1993) distribution function of a flattened, cored isothermal system in analogy to the lowering of the singular, isothermal sphere in ...
1993-10-05
2015-06-24
[ "astro-ph" ]
Konrad Kuijken and John Dubinski
astro-ph/9310008
Bias in Velocity Field Recoveries
We investigate the effect of using different distance estimators on the recovery of the peculiar velocity field of galaxies using Potent. An inappropriate choice of distance estimator will give rise to spurious flows. We discuss methods of minimising these biases and the levels of accuracy required of distance estimato...
1993-10-04
2007-05-23
[ "astro-ph" ]
Andrew Newsam, John F.L. Simmons, Martin Hendry
astro-ph/9310005
Gamma-Ray Bursts and Topology of the Universe
In this letter we propose a physical explanation for recently reported correlations between pairs of close and antipodal gamma-ray bursts from publicly available BATSE catalogue. Our model is based on the cosmological scenario in which bursters are located at cosmological distances of order of 0.5--2~Gpc. Observed dist...
1993-10-04
2007-05-23
[ "astro-ph" ]
Marek Biesiada
astro-ph/9310007
Potent and Max-Flow Algorithms
Although Potent purports to use only radial velocities in retrieving the potential velocity field of galaxies, the derivation of transverse components is implicit in the smoothing procedures. Thus the possibility of using nonradial line integrals to derive the velocity field arises. In the case of inhomogeneous distrib...
1993-10-04
2007-05-23
[ "astro-ph" ]
John F.L. Simmons, Andrew Newsam, Martin Hendry
astro-ph/9310009
Bayesian Estimates of the Large-Scale Velocity Field in Real Space and Redshift Space
Methods for inferring the velocity field from the peculiar velocity data are described and applied to old and newer data. Inhomogeneous Malmquist bias and ways to avoid it are discussed and utilized. We infer that these biases are probably important in interpreting the data.
1993-10-04
2007-05-23
[ "astro-ph" ]
Albert Stebbins
astro-ph/9310004
Some Statistics for Measuring Large-Scale Structure
Good statistics for measuring large-scale structure in the Universe must be able to distinguish between different models of structure formation. In this paper, two and three dimensional ``counts in cell" statistics and a new ``discrete genus statistic" are applied to toy versions of several popular theories of structur...
1993-10-03
2007-05-23
[ "astro-ph", "hep-ph" ]
Robert H. Brandenberger, David M. Kaplan and Stephen A, Ramsey (Brown Univ.)
astro-ph/9310006
On the Limitations of Neutrino Emissivity Formula of Iwamoto
The neutrino emissivity from two and three flavour quark matter is numerically calculated and compared with Iwamoto's formula. We find that the calculated emissivity is smaller than Iwamoto's result by orders of magnitude when $p_{f}(u)+p_{f}(e)-p_{f}(d(s))$ is comparable with the temperature. We attribute it to the se...
1993-10-03
2009-10-22
[ "astro-ph" ]
Sanjay K. Ghosh, S. C. Phatak and Pradip K. Sahu
astro-ph/9310003
Do Gamma-Ray Bursts Come from the Oort Cloud?
We examine the possibility that gamma-ray bursts arise from sources in the Oort comet cloud, basing most of our arguments on accepted models for the formation and spatial distribution of the cloud. We identify three severe problems with such models: (1) There is no known mechanism for producing bursts that can explain ...
1993-10-02
2009-10-22
[ "astro-ph" ]
T. E. Clarke, O. Blaes, adn S. Tremaine
astro-ph/9310002
A Morphology--Cosmology Connection for X--Ray Clusters
We employ N--body/$3D$ gas dynamic simulations of the formation of galaxy clusters to determine whether cluster X--ray morphologies can be used as cosmological constraints. Confirming the analytic expectations of Richstone, Loeb, \& Turner, we demonstrate that cluster evolution is sensitive to the cosmological model in...
1993-10-01
2009-10-22
[ "astro-ph" ]
August Evrard, Joseph Mohr, Daniel Fabricant & Margaret Geller
astro-ph/9310001
A Cosmic String Specific Signature on the Cosmic Microwave Background
Using an analytical model for the string network we show that the kurtosis of cosmic microwave background (CMB) temperature gradient maps is a good statistic to distinguish between the cosmic string model and inflationary models of structure formation. The difference between the stringy and inflationary value for the k...
1993-10-01
2011-05-10
[ "astro-ph", "hep-ph" ]
R. Moessner (Brown Univ.), L. Perivolaropoulos (Harvard-Smithsonian CFA) and R. Brandenberger (Brown Univ.)
astro-ph/9309059
The Growth of Bubbles in Cosmological Phase Transitions
We study how bubbles grow after the initial nucleation event in generic first-order cosmological phase transitions characterised by the values of latent heat, interface tension and correlation length, and driven by a scalar order parameter $\phi$. Equations coupling $\phi$ and the fluid variables $v$ and $T$ and depend...
1993-09-30
2009-10-22
[ "astro-ph", "hep-ph" ]
J. Ignatius, K. Kajantie, H. Kurki-Suonio and M. Laine
astro-ph/9309056
Testing Higher-Order Lagrangian Perturbation Theory Against Numerical Simulations - 1. Pancake Models
We present results showing an improvement of the accuracy of perturbation theory as applied to cosmological structure formation for a useful range of quasilinear scales. The Lagrangian theory of gravitational instability of an Einstein-de Sitter dust cosmogony investigated and solved up to the third order in the series...
1993-09-30
2007-05-23
[ "astro-ph" ]
T.Buchert, A.L.Melott, A.G.Weiss
astro-ph/9309051
Theory of Local Times
A model of a stationary universe is proposed. In this framework, time is defined as a local and quantum-mechanical notion in the sense that it is defined for each local and quantum-mechanical system consisting of finite number of particles. The total universe consisting of infinite number of particles has no time assoc...
1993-09-30
2010-11-19
[ "astro-ph", "gr-qc" ]
Hitoshi Kitada
astro-ph/9309057
Structures in Galaxy Clusters
The analysis of the presence of substructures in 16 well-sampled clusters of galaxies suggests a stimulating hypothesis: Clusters could be classified as unimodal or bimodal, on the basis of to the sub-clump distribution in the {\em 3-D} space of positions and velocities. The dynamic study of these clusters shows that t...
1993-09-30
2009-10-22
[ "astro-ph" ]
E.Escalera, A.Biviano, M.Girardi, G.Giuricin, F.Mardirossian, A.Mazure, and M.Mezzetti