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astro-ph/9309055
Lagrangian theory of gravitational instability of Friedman-Lemaitre cosmologies - generic third-order model for non-linear clustering
The Lagrangian perturbation theory on Friedman-Lemaitre cosmologies investigated and solved up to the second order in earlier papers (Buchert 1992, Buchert \& Ehlers 1993) is evaluated up to the third order. On its basis a model for non-linear clustering applicable to the modeling of large-scale structure in the Univer...
1993-09-30
2015-06-24
[ "astro-ph" ]
Thomas Buchert
astro-ph/9309058
On the Difference between Radio Loud and Radio Quiet AGN
Nuclear jets containing relativistic ``hot'' particles close to the central engine cool dramatically by producing high energy radiation. The radiative dissipation is similar to the famous Compton drag acting upon ``cold'' thermal particles in a relativistic bulk flow. Highly relativistic protons induce anisotropic show...
1993-09-30
2007-05-23
[ "astro-ph" ]
Karl Mannheim
astro-ph/9309053
The metal systems in Q0000--2619 at high resolution
We have obtained high, 11 and 14 \kms, and medium, 40 and 53 \kms, resolution spectra of the $z_{em} = 4.11$ quasar Q0000--2619 covering the range 4400 \AA\ to 9265 \AA . We identify nine metal absorption systems, of which four were previously known. A fifth previously suggested system at $z_{abs} \approx 3.409$ (Turns...
1993-09-30
2011-05-23
[ "astro-ph" ]
Sandra Savaglio, Sandro D'Odorico, Palle M{\o}ller
astro-ph/9309054
Blue perturbation spectra from inflation
We investigate inflationary models leading to density perturbations with a spectral index $n>1$ (``blue spectra"). These perturbation spectra may be useful to simultaneously account for both the amount of ultra large-scale power required to fit cosmic microwave background anisotropies, such as those measured by COBE, a...
1993-09-29
2010-12-09
[ "astro-ph" ]
S. Mollerach, S. Matarrese and F. Lucchin
astro-ph/9309046
Large-Scale Radio Structuers in the Galactic Center
Radio continuum observations of the galactic center region have revealed a number of vertical structures running across the galactic plane. Most of the vertical structures are reasonably attributed either to poloidal magnetic field or to energy release toward the halo. The relation of the continuum structures to the mo...
1993-09-29
2007-05-23
[ "astro-ph" ]
Yoshiaki SOFUE
astro-ph/9309052
Possible Gravitational Microlensing of a Star in the Large Magellanic Cloud
There is now abundant evidence for the presence of large quantities of unseen matter surrounding normal galaxies, including our own$^{1,2}$. The nature of this `dark matter' is unknown, except that it cannot be made of normal stars, dust, or gas, as they would be easily detected. Exotic particles such as axions, massiv...
1993-09-29
2009-10-22
[ "astro-ph", "gr-qc", "hep-ph" ]
C. Alcock, C.W. Akerlof, R.A. Allsman, T.S. Axelrod, D.P. Bennett, S. Chan, K.H. Cook, K.C. Freeman, K. Griest, S.L. Marshall, H-S. Park, S. Perlmutter, B.A. Peterson, M.R. Pratt, P.J. Quinn, A.W. Rodgers, C.W. Stubbs, W. Sutherland, (The MACHO Collaboration)
astro-ph/9309050
A Simulation of the Intracluster Medium with Feedback from Cluster Galaxies
The formation and evolution of an X--ray cluster is studied using a 3--D N-body + hydrodynamical simulation which includes feedback of energy and iron from cluster galaxies. The differences in evolution and final state between the simulation and a similar run without feedback are highlighted. We address the energetics ...
1993-09-29
2008-11-26
[ "astro-ph" ]
Christopher A. Metzler and August E. Evrard
astro-ph/9309045
Ram-Pressure Stripping of Gas from Companions and Accretion onto a Spiral Galaxy: A Gaseous Merger
We simulated the behavior of interstellar gas clouds in a companion galaxy during a gas-dynamical interaction with the halo and disk of a spiral galaxy. By ram pressure, the gas clouds are stripped from the companion, and accreted to ward the disk of the spiral galaxy. If the companion's orbit is retrograde with respec...
1993-09-29
2009-10-22
[ "astro-ph" ]
Yoshiaki SOFUE
astro-ph/9309047
Face-on Barred Spiral Structure of Molecular Clouds in M31's Bulge
By image processing and color excess analyses of B, V, R, and I-band CCD images of the central region of M31 taken with the Kiso 105-cm Schmidt telescope, we found a bar of 200 pc length. We also found a more extended ``face-on" spiral feature of dark clouds, which appear t o be connected to this bar and is probably an...
1993-09-29
2007-05-23
[ "astro-ph" ]
Y.Sofue, S.Yoshida, T. Aoki, T. Soyano, M. Hamabe, and K. Wakamatsu
astro-ph/9309048
Scrutinizing Supergravity Models through Neutrino Telescopes
Galactic halo neutralinos ($\chi$) captured by the Sun or Earth produce high-energy neutrinos as end-products of various annihilation modes. These neutrinos can travel from the Sun or Earth cores to the neighborhood of underground detectors (``neutrino telescopes") where they can interact and produce upwardly-moving mu...
1993-09-29
2009-08-25
[ "astro-ph", "hep-ph" ]
Raj Gandhi, Jorge L. Lopez, D.V.Nanopoulos, Kajia Yuan, and A. Zichichi
astro-ph/9309049
Confrontation of a Double Inflationary Cosmological Model with Observations
CDM models with non-scale-free step-like spectra of adiabatic perturbations produced in a realistic double inflationary model are compared with recent observational data. The model contains two additional free parameters relatively to the standard CDM model with the flat ($n=1$) initial spectrum. Results of the COBE ex...
1993-09-29
2010-12-09
[ "astro-ph" ]
Stefan Gottloeber, Jan P. Muecket and A. Starobinsky
astro-ph/9309043
Comments on Inflationary Cosmology
In this talk we discuss three different issues. First of all, there exist several proposals how to solve cosmological problems by adiabatic expansion of the Universe, without any use of inflation. We explain why these models do not solve the flatness/entropy problem. On the other hand there exist some claims that infla...
1993-09-28
2007-05-23
[ "astro-ph" ]
Andrei Linde
astro-ph/9309041
Measuring Cosmological Parameters with Cosmic Microwave Background Experiments
The cosmic microwave background anisotropy is sensitive to the slope and amplitude of primordial energy density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history, {\it etc.} In this Letter, we examine the degree to which these factors can be ...
1993-09-28
2008-11-26
[ "astro-ph" ]
J. R. Bond, Robert Crittenden, Richard L. Davis, George Efstathiou and Paul J. Steinhardt
astro-ph/9309044
A Family of Models for Spherical Stellar Systems
We describe a one-parameter family of models of stable spherical stellar systems in which the phase-space distribution function depends only on energy. The models have similar density profiles in their outer parts ($\rho\propto r^{-4}$) and central power-law density cusps, $\rho\propto r^{3-\eta}$, $0<\eta\le 3$. The f...
1993-09-28
2009-10-22
[ "astro-ph" ]
S. Tremaine. D. O. Richstone, Y.-I. Byun, A. Dressler, S. M. Faber, C. Grillmair, J. Kormendy, and T. R. Lauer
astro-ph/9309042
Why Disks Shine: the Transport of Angular Momentum in Hot, Thin Disks
I review recent work on the radial transport of angular momentum in ionized, Keplerian accretion disks. Proposed mechanisms include hydrodynamic and MHD local instabilities and long range effects mediated by wave transport. The most promising models incorporate the Velikhov-Chandrasekhar instability, caused by an insta...
1993-09-28
2007-05-23
[ "astro-ph" ]
E.T. Vishniac
astro-ph/9309039
Galaxy Velocity Field in Tilted Cold Dark Matter Models
We study the cosmic peculiar velocity field as traced by a sample of 1184 spiral, elliptical and S0 galaxies, grouped in 704 objects. We carry out a statistical analysis, by calculating bulk flows and velocity correlation functions for this sample and for mock catalogs which we extract from N--body simulations. For the...
1993-09-27
2007-05-23
[ "astro-ph" ]
F. Lucchin, S. Matarrese, L. Moscardini and G. Tormen
astro-ph/9309040
Nonlinear Effects due to the Coupling of Long-Wave Modes
The cosmological fluid equations are used to study the nonlinear mode coupling of density fluctuations. We find that for realistic cosmological spectra there is a significant contribution to the nonlinear evolution on scales of interest to large-scale structure from the long-wave part of the initial spectrum. A consequ...
1993-09-27
2007-05-23
[ "astro-ph" ]
Bhuvnesh Jain and Edmund Bertschinger
astro-ph/9309038
Do Spirals and Ellipticals Trace the Same Velocity Field?
We test the hypothesis that the velocity field derived from Tully-Fisher measurements of spiral galaxies, and that derived independently from Dn-sigma measurements of ellipticals and S0s, are noisy versions of the same underlying velocity field. The radial velocity fields are derived using tensor Gaussian smoothing of ...
1993-09-27
2009-10-22
[ "astro-ph" ]
T. Kolatt and A. Dekel
astro-ph/9309037
A Multiwavelength Study of Star Formation in the L1495E Cloud in Taurus
We have carried out a deep (t=30000s) x-ray search of the eastern portion of the L1495 cloud centered on the well known weak line T Tauri star (WTTS) V410 Tau using the ROSAT PSPC. This deep exposure enabled a search for candidate pre-main sequence (PMS) objects in this cloud to a limit 20 times more sensitive than tha...
1993-09-26
2011-02-11
[ "astro-ph" ]
Karen M. Strom, Stephen E. Strom
astro-ph/9309036
Reheating during Hierarchical Clustering in the Universe Dominated by the Cold Dark Matter
We investigate reheating of the universe by early formation of stars and quasars in the hierarchical clustering scheme of cold dark matter scenario, with perturbation fluctuations normalized by the COBE data. It is found that ionizing uv flux from OB stars with the abundance given by the standard initial mass function ...
1993-09-25
2015-06-24
[ "astro-ph" ]
M. Fukugita and M. Kawasaki
astro-ph/9309035
Parallel P3M with exact calculation of short range forces
A P3M (Particle-Particle, Particle-Mesh) algorithm to compute the gravitational force on a set of particles is described. The gravitational force is computed using Fast Fourier Transforms. This leads to an incorrect force when the distance between two particles is of the order of a grid cell. This incorrect force is su...
1993-09-24
2009-10-22
[ "astro-ph" ]
T. Theuns
astro-ph/9309034
The Zero-Point of the Cluster-Cluster Correlation Function: A Key Test of Cosmological Power Spectra
We propose the zero-point of the cluster-cluster correlation function as a sensitive test for the shape of the power spectrum of initial fluctuations. It is now possible to go beyond the power law description to measure the point at which the correlation function becomes zero. Four independent measurements indicate tha...
1993-09-22
2009-10-22
[ "astro-ph" ]
Anatoly Klypin and George Rhee
astro-ph/9309033
Testing Models for Structure Formation
I review a number of tests of theories for structure formation. Large-scale flows and IRAS galaxies indicate a high density parameter $\Omega \simeq 1$, in accord with inflationary predictions, but it is not clear how this meshes with the uniformly low values obtained from virial analysis on scales $\sim$ 1Mpc. Gravita...
1993-09-21
2007-05-23
[ "astro-ph", "hep-ph" ]
Nick Kaiser
astro-ph/9309032
Supercooling and Nucleation in Phase Transitions of the Early Universe -
The three phase transitions - the GUT, the electro-weak and the quark-hadron, which the universe is assumed to have undergone produce very important physical effects if they are assumed to be of first order. It is also important that enough supercooling is produced at these transitions so that the rate of nucleation of...
1993-09-21
2015-06-24
[ "astro-ph", "hep-ph" ]
B.Banerjee and R. V. Gavai
astro-ph/9309030
Spherical Harmonic Reconstruction of Cosmic Density and Velocity Fields
The orthonormal set of Spherical Harmonics provides a natural way of expanding whole sky redshift and peculiar velocity surveys.
1993-09-20
2009-09-25
[ "astro-ph" ]
Ofer Lahav
astro-ph/9309029
A Spherical Harmonic Approach to Redshift Distortion: Implications for $\Omega$ and the Power Spectrum
We examine the nature of galaxy clustering in redshift space using a method based on an expansion of the galaxian density field in Spherical Harmonics and linear theory. We derive a compact and self-consistent expression for the distortion when applied to flux limited redshift surveys. The amplitude of the distortion i...
1993-09-20
2007-05-23
[ "astro-ph" ]
Karl B. Fisher
astro-ph/9309031
Cosmological Parameters from Spherical Harmonic Analyses
In the rest of this volume Lahav and Fisher have presented the method of Spherical Harmonic Analysis (SHA) and its use in estimating cosmologically interesting parameters. Here I demonstrate the use of SHA in cross-correlating galazy catalogues and present an estimate of the ratio of the optical and IRAS galaxy bias pa...
1993-09-20
2007-05-23
[ "astro-ph" ]
Caleb. A. Scharf
astro-ph/9309028
Determining Omega from Peculiar Velocities
The large-scale dynamics of matter is inferred from the observed peculiar velocities of galaxies via the POTENT procedure. The smoothed fields of velocity and mass-density fluctuations are recovered from the current data of about 3000 galaxies. The cosmological density parameter Omega can then be constrained in three w...
1993-09-19
2007-05-23
[ "astro-ph" ]
Avishai Dekel
astro-ph/9309027
A Spherical Harmonic Approach to Redshift Distortion and a Measurement of Omega from the 1.2 Jy IRAS Redshift Survey
We present a formalism for analysing redshift distortions based on a spherical harmonic expansion of the density field. We use a maximum likelihood estimator for the combination of density and bias parameters, $\Omega^0.6/b$. We test the method with $N$-body simulations and apply it to the 1.2 Jy IRAS redshift survey.
1993-09-18
2015-06-24
[ "astro-ph" ]
Karl B. Fisher, Caleb A. Scharf, and Ofer Lahav
astro-ph/9309025
Astrophysical aspects of fermion number violation in the supersymmetrical standard model
The model of the supersymmetrical ball in the supersymmetrical standard model with additional global U(1) fermion symmetry is presented. We show that the supersymmetry breaking scale ( R-parity ), the global U(1) fermion symmetry scale and the electroweak symmetry breaking scale are strictly connected to each other. Th...
1993-09-17
2009-10-22
[ "astro-ph" ]
R.Manka, I.Bednarek
astro-ph/9309026
A Cautionary Note on Gamma Ray Burst Nearest Neighbor Statistics
In this letter we explore the suggestion of Quashnock and Lamb (1993) that nearest neighbor correlations among gamma ray burst positions indicate the possibility of burst repetitions within various burst sub-classes. With the aid of Monte Carlo calculations we compare the observed nearest neighbor distributions with th...
1993-09-17
2007-05-23
[ "astro-ph" ]
Michael A. Nowak
astro-ph/9309023
The Fourier Space Statistics of Seedlike Cosmological Perturbations
We propose a new test for distinguishing observationally cosmological models based on seed-like primordial perturbations (like cosmic strings or textures), from models based on Gaussian fluctuations. We investigate analytically the {\it Fourier space} statistical properties of temperature or density fluctuation pattern...
1993-09-16
2015-06-24
[ "astro-ph", "hep-ph" ]
Leandros Perivolaropoulos (Harvard-Smithsonian CfA)
astro-ph/9309024
Kinematical and Dynamical Approaches to Gravitational Instability
This paper reviews the essential physics of gravitational instability in a Robertson-Walker background spacetime. Three approaches are presented in a pedagogical manner, based on (1) the Eulerian fluid equations, (2) the Lagrangian description of trajectories, and (3) the Lagrangian fluid equations. Linear and nonlinea...
1993-09-16
2007-05-23
[ "astro-ph" ]
Edmund Bertschinger
astro-ph/9309022
Measuring Bulk Flows in Large Scale Surveys
We follow a formalism presented by Kaiser to calculate the variance of bulk flows in large scale surveys. We apply the formalism to a mock survey of Abell clusters \'a la Lauer \& Postman and find the variance in the expected bulk velocities in a universe with CDM, MDM and IRAS--QDOT power spectra. We calculate the vel...
1993-09-15
2007-05-23
[ "astro-ph" ]
Hume A. Feldman and Richard Watkins
astro-ph/9309020
Angular Diameters of Compact Planetary Nebulae
We have obtained H$\alpha$ CCD images of 21 compact planetary nebulae in the galactic bulge. All objects are resolved and, after deconvolving the seeing disk, we find diameters of 1--2$''$ with typical uncertainties of 20\%. The values are generally in good agreement with radio measurements but are smaller than older o...
1993-09-14
2011-05-23
[ "astro-ph" ]
Timothy R. Bedding and Albert A. Zijlstra
astro-ph/9309021
Cosmological Velocity Bias
Velocity bias is a reduction of the velocity dispersion of tracer galaxies in comparison to the velocity dispersion of the underlying mass field. There are two distinct forms of velocity bias. The single particle velocity reduction, $b_v(1)$, is the result of energy loss of a tracer population, and in virialized region...
1993-09-14
2008-02-03
[ "astro-ph" ]
Ray Carlberg
astro-ph/9309018
Neutrino Process Nucleosynthesis and the $^{11}$B/$^{10}$B Ratio
We consider the evolution of the light elements ($Li, Be$ and $B$) incorporating the effects of their production by both neutrino process and cosmic-ray nucleosynthesis. We test the viability of the neutrino process to resolve the long standing problem of the $^{11}$B/$^{10}$B isotopic ratio which amounts to 4 at the t...
1993-09-13
2009-09-25
[ "astro-ph" ]
Keith A. Olive, Nikos Prantzos, Sean Scully, and Elisabeth Vangioni-Flam
astro-ph/9309019
High-order galaxy correlation functions in the APM Galaxy Survey
We estimate J-point galaxy averaged correlation functions $\wbar_J(\theta)$ for $J=2,...,9$, in a sample of the APM Galaxy Survey with more than $1.3 \times 10^6$ galaxies and a depth $ \calD \sim 400 \Mpc$. The hierarchical amplitudes $s_J=\wbar_J/\wbar_2^{J-1}$ are roughly constant, up to $J=9$, between $0.5 \Mpc$ an...
1993-09-13
2015-06-24
[ "astro-ph" ]
Enrique Gaztanaga
astro-ph/9309017
Constraints on Chaotic Inflation from the COBE DMR results
We explore constraints on various forms for the effective potential during inflation based upon a statistical comparison between inflation-generated fluctuations in the cosmic microwave background temperature and the COBE DMR results. Fits to the COBE 53A+B x 90A+B angular correlation function are obtained using simple...
1993-09-13
2007-05-23
[ "astro-ph", "hep-ph" ]
Hannu Kurki-Suonio and Grant Mathews
astro-ph/9309016
The Past and Present Infrared Spectrum of BD+30 3639
We present a radiative-transfer calculation which reproduces the infrared spectrum of the planetary nebula BD+30$^{\circ}$3639, fitting both the spectral energy distribution and the spatial extent at infrared wavelengths. We obtain an acceptable fit to most of the spectrum, including the infrared bands. The fit require...
1993-09-13
2007-05-23
[ "astro-ph" ]
Albert A. Zijlstra and Ralf Siebenmorgen
astro-ph/9309014
Standard and Non-Standard Plasma Neutrino Emission Revisited
On the basis of Braaten and Segel's representation of the electromagnetic dispersion relations in a QED plasma we check the numerical accuracy of several published analytic approximations to the plasma neutrino emission rates. As we find none of them satisfactory we derive a new analytic approximation which is accurate...
1993-09-10
2009-10-22
[ "astro-ph" ]
M. Haft, G. Raffelt, and A. Weiss
astro-ph/9309015
A New Radiation Hydrodynamics Code and Application to the Calculation of Type Ia Supernovae Light Curves and Continuum Spectra
A new, fully dynamic and self-consistent radiation hydrodynamics code, suitable for the calculation of supernovae light curves and continuum spectra, is described. It is a multigroup (frequency-dependent) code and includes all important $O(v/c)$ effects. It is applied to the model W7 of Nomoto, Thielemann, \& Yokoi (19...
1993-09-10
2009-10-22
[ "astro-ph" ]
Xiao-he Zhang and Peter Sutherland
astro-ph/9309013
On the shape of the light profiles of early-type galaxies
We have obtained the best fit to the light profiles of a luminosity limited sample of elliptical and S0 galaxies with a power law \rn, letting the exponent remain free rather than keeping it fixed at $1/n=1/4$ as in the well known \GV formula. The introduction of a free parameter in the fitting formula (ranging from $n...
1993-09-10
2015-06-24
[ "astro-ph" ]
N. Caon, M. Capaccioli and M. D'Onofrio
astro-ph/9309011
Gamma-Ray Bursts: Multiwaveband Spectral Predictions for Blast Wave Models
In almost any scenario for 'cosmological' gamma-ray bursts (and in many models where they originate in our own Galaxy), the initial energy density is so large that the resulting relativistic plasma expands with $v\sim c$ producing a blast wave ahead of it and a reverse shock moving into the ejecta, as it ploughs into t...
1993-09-09
2009-10-22
[ "astro-ph" ]
P. Meszaros and M.J. Rees
astro-ph/9309012
Gamma-Ray Bursts from Blast Waves Around Galactic Nuetron Stars
If gamma-ray bursts originate in our Galaxy, they probably involve violent disturbances in the magnetospheres of neutron stars. Any event of this kind is likely to trigger the sudden expulsion of magnetic flux and plasma at relativistic speed. We show that such ejecta would be braked by the interstellar medium (ISM), a...
1993-09-09
2016-06-08
[ "astro-ph" ]
Mitchell C. Begelman, P. Meszaros, and Martin J. Rees
astro-ph/9309010
Cavitation of Matter in the Universe into a Degenerated Voronoi Foam
Fluids suspended in expanding laboratory systems cavitate into Voronoi foams that degenerate through secondary cavitation of the foam walls. This robust morphological mechanism results from a virtual competition for space between the cavities. In cosmology, Voronoi foams are known to explain important features of the l...
1993-09-09
2007-05-23
[ "astro-ph" ]
T. Norretranders, J. Bohr, and S. Brunak
astro-ph/9309009
On the Prediction of Velocity Fields from Redshift Space Galaxy Samples
We present a new method for recovering the underlying velocity field from an observed distribution of galaxies in redshift space. The method is based on a kinematic Zel'dovich relation between the velocity and density fields in redshift space. This relation is expressed in a differential equation slightly modified from...
1993-09-08
2009-10-22
[ "astro-ph" ]
Adi Nusser and Marc Davis
astro-ph/9309008
Sub-Arcsecond 2D Photometry and Spectrography of the Nucleus of M31: The Supermassive Black Hole Revisited
Sub-arcsecond imagery (HRCAM, 0".35 - 0".57 FWHM) and two-dimensional spectrography (TIGER, 0".9 FWHM) of the central nucleus of M31 have been obtained at CFHT. The photometric data clearly show the double-peaked nucleus, in excellent agreement with a recent HST image by Lauer et al. 1993. We built deconvolved surface ...
1993-09-03
2007-05-23
[ "astro-ph" ]
R. Bacon, E. Emsellem, G. Monnet and J.L. Nieto
astro-ph/9309007
Infrared Searches for Dark Matter in the Form of Brown Dwarfs
Brown dwarfs, stars with insufficient mass to burn hydrogen, could contribute to the dark matter in the Galactic disk, galactic halos or even a background critical density. We consider the detectability of such brown dwarfs in various scenarios, extending previous work by allowing for the possibility that they may have...
1993-09-02
2015-06-24
[ "astro-ph" ]
E. J. Kerins & B. J. Carr
astro-ph/9309006
Implications of MAX for CDM
We analyze the Gamma Ursae Minoris (GUM) and Mu Pegasii (MuP) scans of the Millimeter-wave Anisotropy eXperiment in the context of cold dark matter (CDM) models of structure formation, paying particular attention to the two-dimensional nature of the GUM scan. If all of the structure in the (foreground subtracted) data ...
1993-09-01
2008-11-26
[ "astro-ph", "hep-ph" ]
Mark Srednicki, Martin White, Douglas Scott and Emory T. Bunn
astro-ph/9309005
Star counts in NGC 6397
I-band CCD images of a large area of the nearby globular cluster NGC~6397 have been used to construct a surface density profile and two luminosity and mass functions. The surface density profile extends out to 14\arcm from the cluster center and shows no sign of a tidal cutoff. The inner profile is a power-law with slo...
1993-09-01
2009-10-22
[ "astro-ph" ]
G. A. Drukier, G. G. Fahlman, H.B. Richer, L. Searle, and I. Thompson
astro-ph/9309003
Maximum-Likelihood Analysis of the COBE Angular Correlation Function
We have used maximum-likelihood estimation to determine the quadrupole amplitude $Q_{\rm rms-PS}$ and the spectral index $n$ of the density fluctuation power spectrum at recombination from the \cobe\ DMR data. We find a strong correlation between the two parameters of the form $Q_{\rm rms-PS}=(15.7\pm 2.6)\exp[0.46(1-n...
1993-09-01
2009-10-22
[ "astro-ph" ]
Uros Seljak and Edmund Bertschinger
astro-ph/9309002
Reconciliation of the Disparate Gamma-Ray Burst Catalogs in the Context of a Cosmological Source Distribution
It is well known that Gamma-ray Burst spectra often display a break at energies $\simless 400$ keV, with some exceptions extending to several MeV.\ \ Modeling of a cosmological source population is thus non-trivial when comparing the catalogs from instruments with different energy windows since this spectral structure ...
1993-09-01
2009-10-22
[ "astro-ph" ]
Peter Tamblyn and Fulvio Melia
astro-ph/9309004
Formation of spiral and elliptical galaxies in a CDM cosmogony
The formation of galaxies in a CDM cosmogony is investigated by following the evolution of dark and baryonic matter and of the frequency- dependent spatially averaged radiation field. The gas is allowed to form stars which are independently treated as a fourth collisionless component. By supernovae, energy and metal en...
1993-09-01
2007-05-23
[ "astro-ph" ]
Matthias Steinmetz and Ewald Mueller
astro-ph/9308047
Pre-main sequence lithium burning. I. Weak T Tauri stars
We derive lithium abundances in 53 T Tauri stars (TTS), concentrating on weak-line TTS. Our study gives the following results: 1)At luminosities $\ge 0.9 L\sun$ the Li abundances are remarkably uniform, with a mean value, log~N(Li)=3.1, equal to the "cosmic" lithium abundance. 2)Significant Li depletion appears below 0...
1993-08-31
2019-08-17
[ "astro-ph" ]
E.L.Martin, R.Rebolo, A.Magazzu, Ya.V.Pavlenko
astro-ph/9309001
The Effect of Dissipation on the Shapes of Dark halos
The dissipative infall of gas during the formation of a galaxy modifies the density profile and shape of the dark halo. Gas dissipates energy radiatively and sinks to the center of the dark halo forming the luminous part of a galaxy. The resulting central density enhancement can alter the halo's orbital distribution. W...
1993-08-31
2009-10-22
[ "astro-ph" ]
John Dubinski
astro-ph/9308048
Are Gamma-Ray Bursts at Cosmological Distances Optically-Thin?
The observed spatial distribution of $\gamma-$ray bursts indicates that they probably originate at cosmological distances. At this distance scale their variability timescale and flux above MeV imply an initial optical-depth to pair production $> 10^{10}$. This appears to be in conflict with their highly non-thermal spe...
1993-08-31
2010-01-06
[ "astro-ph" ]
Abraham Loeb
astro-ph/9308045
Co Observations of Edge-on Galaxies. IV, NGC 4565: Radial Variation of the H2-to-Hi Ratio
The edge-on galaxy NGC 4565 has been observed in the 12CO(J=1-0)-line emission using the Nobeyama 45-m telescope with an angular resolution of 15". We obtained a scan along the major axis for +/-5' (+/- 15 kpc) about the galactic center, and some scans perpendicular to the galactic plane. The radial density distributio...
1993-08-31
2007-05-23
[ "astro-ph" ]
Y. Sofue and N. Nakai
astro-ph/9308046
Gravothermal Expansion in an $N$-Body System
This paper describes the numerical evolution of an $N$-body system with a slight ``temperature inversion''; i.e. the maximum velocity dispersion occurs not at the centre but further out. Fluid models predict that the core of such a system expands on a time-scale of thousands of central relaxation times, and here this b...
1993-08-31
2015-06-24
[ "astro-ph" ]
Douglas C. Heggie, Shogo Inagaki and Stephen L.W. McMillan
astro-ph/9308044
Reconstructing the Inflaton Potential---Perturbative Reconstruction to Second Order
One method to reconstruct the scalar field potential of inflation is a perturbative approach, where the values of the potential and its derivatives are calculated as an expansion in departures from the slow-roll approximation. They can then be expressed in terms of observable quantities, such as the square of the ratio...
1993-08-30
2013-11-13
[ "astro-ph", "hep-ph" ]
Edmund Copeland, Edward W. Kolb, Andrew R. Liddle, and James E. Lidsey
astro-ph/9308043
Constraints in the Context of Induced-gravity Inflation
Constraints on the required flatness of the scalar potential $V(\phi)$ for a cousin-model to extended inflation are studied. It is shown that, unlike earlier results, Induced-gravity Inflation can lead to successful inflation with a very simple lagrangian and $\lambda \sim 10^{-6}$, rather than $10^{-15}$ as previously...
1993-08-28
2009-10-22
[ "astro-ph", "gr-qc" ]
David I. Kaiser
astro-ph/9308042
Dynamically Comptonized Spectra from Near Critical Accretion onto Neutron Stars
We investigate the effects of dynamical Comptonization on the emergent radiation spectrum produced by near critical accretion onto a neutron star. The flow dynamics and the transfer of radiation are self--consistently solved in the case of a spherically symmetric, ``cold'', pure scattering flow, including general relat...
1993-08-27
2009-10-22
[ "astro-ph" ]
Luca Zampieri, Roberto Turolla and Aldo Treves
astro-ph/9308041
Constraints on the Strength of a Primordial Magnetic Field from Big Bang Nucleosynthesis
The effects of magnetic fields on Big Bang Nucleosynthesis(BBN) have been calculated, and the impact on the abundances of the light elements have been investigated numerically. An upper limit on the strength of primordial magnetic fields compatible with observations of light element abundances has been thus obtained. I...
1993-08-27
2009-12-30
[ "astro-ph" ]
Baolian Cheng, David N. Schramm, and James W. Truran
astro-ph/9308040
A Possible Explanation for the Peculiar Correlations in the Angular Distribution of Gamma-Ray Bursts
It has been recently discovered that the angular autocorrelation function of gamma-ray bursts exhibits sharp peaks at angular separations of $\lesssim 4\deg$ (Quashnock and Lamb 1993), and at $\gtrsim 176\deg$ (Narayan and Piran 1993). While an excess of very close pairs of bursts can naturally arise from burst repetit...
1993-08-27
2016-06-08
[ "astro-ph" ]
Eyal Maoz
astro-ph/9308037
A Polar-Nulceus Dark Lane in the Barred Spiral M83: Three-Dimensional Accretion in the Nucleus
The central region of the barred spiral galaxy M83 reveals a polar-nucleus dust lane, wh ich extends from the NE molecular bar and crosses the central bulge. Its SW counterpart is not visible, being hidden behind the bulge. This asymmetry, in spite of the galaxy's face-on orientation and the symmetric bar struct ure in...
1993-08-27
2009-10-22
[ "astro-ph" ]
Y. Sofue and K. Wakamatsu
astro-ph/9308039
Feasibility study of a Superheated Superconducting Granule detector for cold dark matter search
The presented results are part of a feasibility study of a Super- heated Superconducting Granule (SSG) device for weakly interacting massive particles (WIMPs) detection. The sensitivity of SSG to nuclear recoils has been explored irradiating SSG detectors with a 70Me$\!$V neutron beam proving that energy thresholds of ...
1993-08-27
2009-09-25
[ "astro-ph" ]
A. Gabutti, et al
astro-ph/9308038
CO versus HI in the Tully-Fisher relation for a sample of 32 galaxies
As a basic step for establishing the CO-line Tully-Fisher relation for distant galaxies, we made a comparative study of HI versus CO line profiles. Total line profiles of the CO line emission from 32 galaxies have been compared with the corresponding HI emission. We found a good correlation between the profiles of CO a...
1993-08-27
2007-05-23
[ "astro-ph" ]
F.Schoeniger and Y.Sofue
astro-ph/9308036
Co Emission from Molecular Clouds in the Central Region of M31
We detected \co-line emission from a complex of dark cloud located at about 250 pc from M 31's center, which is the most conspicuous extinction feature within the central few hund red pc as observed in $B,V,R,I$-band CCD imaging. The darkest cloud has a 30-pc size, and the virial mass is estimated to be $\sim 8.7\time ...
1993-08-27
2009-10-22
[ "astro-ph" ]
Yoshiaki SOFUE, and Shigeomi YOSHIDA
astro-ph/9308035
Interaction Rates at High Magnetic Field Strengths and High Degeneracy
In this paper, we have derived the the effects of strong magnetic fields ${\bf \vec B}$ on nucleon and particle reaction rates of astrophysical significance. We have explored the sensitivity to the presence of arbitrary degeneracy and polarization. The possible astrophysical applications of our results are discussed.
1993-08-26
2009-10-22
[ "astro-ph" ]
Baolian Cheng, David N. Schramm, and James W. Truran
astro-ph/9308033
On the Relationship between BL-Lacertae Objects and FRI Radio Galaxies
The idea that Fanaroff-Riley Class~I Radio Galaxies contain core jets with Lorentz factors of the order of a few and are the parent population for BL~Lac Objects is examined, with particular reference to the data on two FRI Radio Galaxies, NGC~315 and NGC~6251. Conservation laws for an entraining relativistic jet are d...
1993-08-25
2009-10-22
[ "astro-ph" ]
Geoffrey V. Bicknell
astro-ph/9308034
Beamed Radiation in Radio Galaxies
This paper focuses on two aspects of the Physics of Radio Galaxies in which it has been proposed that relativistic beaming of radiation is necessary to account for the observations. Physical arguments are presented which show that it is quite plausible that the jets in FRI radio galaxies are relativistic on the parsec ...
1993-08-25
2007-05-23
[ "astro-ph" ]
Geoffrey V. Bicknell
astro-ph/9308032
Dynamical Theory of Groups and Clusters of Galaxies
The different dynamical processes (relaxation, dynamical friction, tides and mergers) operating in groups and clusters are reviewed. The small-scale substructure observed in clusters is argued to be the remnants of the cores of rich clusters that merged together, rather than large groups falling into the cluster. The {...
1993-08-24
2007-05-23
[ "astro-ph" ]
Gary A. Mamon
astro-ph/9308031
The Galactic Center radio jet
Recent observations of the radio and NIR source Sgr A* reinforce the interpretation of the Galactic Center as a scaled down version of an AGN. The discovery of an elongated structure at 43 GHz and increasing evidence for the presence of an accretion disk surrounding a Black Hole lead us to assume that both, an accretio...
1993-08-24
2011-05-23
[ "astro-ph" ]
Heino Falcke, Karl Mannheim, Peter L. Biermann
astro-ph/9308030
The Galactic Center - an AGN on a starvation diet
The Galactic Center shows evidence for the presence of three important AGN ingredients: a Black Hole ($M_\bullet\sim10^6M_\odot$), an accretion disk ($10^{-8.5} - 10^{-7} M_\odot/{\rm yr}$) and a powerful jet (jet power $\ge$ 10\% disk luminosity). However, the degree of activity is very low and can barely account for ...
1993-08-24
2007-05-23
[ "astro-ph" ]
Heino Falcke & Peter L. Biermann
astro-ph/9308029
Omega from Velocities in Voids
We propose a method for deriving a dynamical lower bound on $\Omega$ from diverging flows in low-density regions, based on the fact that large outflows are not expected in a low-$\Omega$ universe. The velocities are assumed to be induced by gravity from small initial fluctuations, but no assumptions are made regarding ...
1993-08-23
2009-10-22
[ "astro-ph" ]
Avishai Dekel and Martin Rees
astro-ph/9308027
Confrontation of the Lauer and Postman Cluster Velocity Field with Models
The large-scale bulk flow implied by the measurements of distances to brightest cluster members within 15,000 km/s by Lauer and Postman has the potential to put strong constraints on, or to even rule out, various models of large-scale structure. Using PM simulations 400$h^{-1}$ Mpc on a side of five cosmological models...
1993-08-20
2007-05-23
[ "astro-ph" ]
Michael Strauss, Renyue Cen, and Jeremiah Ostriker
astro-ph/9308028
Tests of the Hubble Law from the Luminosity Function of IRAS Galaxies
All direct measurements of peculiar velocities of glaxies assume the Hubble law at low redshifts. However, it has been suggested by Segal et al (1993) that the correlation of redshifts and fluxes in a complete sample of IRAS galaxies is inconsistent with the Hubble law, and instead implies that redshifts are proportion...
1993-08-20
2007-05-23
[ "astro-ph" ]
Michael Strauss and Daniel Koranyi
astro-ph/9308025
Errata in \em {Enclyclopedia of Cosmology}
I have noted a number of errors, most of them quite minor, in the {\em Encyclopedia of Cosmology} (New York and London: Garland), 1993, Norriss S. Hetherington, ed. The majority occur in my mathematically verbose article, ``Fundamental cosmological parameters". Some errata were passed on to me by Prof. Ralph Alpher. In...
1993-08-20
2007-05-23
[ "astro-ph" ]
Kevin Krisciunas (Joint Astronomy Centre, Hilo, Hawaii, USA)
astro-ph/9308026
Production of Li, Be \& B from Baryon Inhomogeneous Primordial Nucleosynthesis
We investigate the possibility that inhomogeneous nucleosynthesis may eventually be used to explain the abundances of \li6, \be9 and B in population II stars. The present work differs from previous studies in that we have used a more extensive reaction network. It is demonstrated that in the simplest scenario the abund...
1993-08-20
2009-09-15
[ "astro-ph", "hep-ph" ]
David Thomas, David N. Schramm, Keith A. Olive, Grant J. Mathews, Bradley S. Meyer, Brian D. Fields
astro-ph/9308024
Cored Apple Bipolarity : A Global Instability to Convection in Radial Accretion?
We propose that the prevalence of bipolarity in Young Stellar Objects is due to the fine tuning that is required for spherical accretion of an ambient medium onto a central node.It is shown that there are two steady modes that are more likely than radial accretion, each of which is associated with a hyperbolic central ...
1993-08-19
2015-06-24
[ "astro-ph" ]
R.N. Henriksen and D. Valls-Gabaud
astro-ph/9308022
Can the Dark Matter be $10^6$ Solar Mass Objects?
If the dark matter in galactic halos is made up of compact, macroscopic objects (MO), such as black holes with $M_\MO >>M_{stars}$, gravitational scattering will lead to kinematic heating of the stars. Observational constraints on the amount of heating in the disk of the Milky Way put upper limits on $M_\MO \ltorder 10...
1993-08-17
2009-10-22
[ "astro-ph" ]
Hans-Walter Rix and George Lake
astro-ph/9308023
A Neutral Hydrogen Survey of Polar-Ring Galaxies: I. Green Bank Observations of the Northern Sample
We present the results of a neutral hydrogen survey conducted with the Green Bank 140-foot radio telescope of 47 northern objects in the polar-ring galaxy atlas of Whitmore \etal\ (1990). We detected 39 of these above our detection limit of 1.7 \hbox{Jy\CDOT\KMS}; the average measured flux of 21 Jy\CDOT\KMS\ correspond...
1993-08-17
2008-11-26
[ "astro-ph" ]
O.-G. Richter, P.D. Sackett and L.S. Sparke
astro-ph/9308021
Are SP91 and COBE Inconsistent with Cold Dark Matter?
We present results on the consistency of standard cold dark matter (CDM) models with both the COBE normalization and the data from the 4th channel of the 9-point South Pole scan. We find that CDM models are consistent with both experiments, a conclusion which is at odds with some other analyses. This is partly due to o...
1993-08-17
2008-11-26
[ "astro-ph", "hep-ph" ]
E. Bunn, M. White, M. Srednicki, and D. Scott
astro-ph/9308020
The Optical Polarization Properties of X-ray Selected BL Lacertae Objects
We discuss the optical polarization properties of X-ray selected BL Lacertae objects (XSBLs) as determined from three years of monitoring 37 BL Lac objects and candidates. The observed objects include a complete X-ray flux limited sample drawn from the EMS Survey. The majority of the XSBLs classi- fied solely on the ap...
1993-08-16
2009-10-22
[ "astro-ph" ]
B.T. Jannuzi, P.S. Smith & R. Elston
astro-ph/9308019
Re-Ionization and its Imprint on the Cosmic Microwave Background
Early reionization changes the pattern of anisotropies expected in the cosmic microwave background. To explore these changes, we derive from first principles the equations governing anisotropies, focusing on the interactions of photons with electrons. Vishniac (1987) claimed that second order terms can be large in a re...
1993-08-16
2009-10-22
[ "astro-ph" ]
Scott Dodelson and Jay Jubas
astro-ph/9308018
Why is the Temperature of the Universe 2.726K?
NASA's Cosmic Background Explorer (COBE) Satellite has recently made the most accurate measurement of the temperature of the Universe determining it to be $2.726\pm 0.01\,$K. In trying to understand why the temperature has this value, one is led to discover the most fundamental features of the Universe---an early, radi...
1993-08-13
2009-10-22
[ "astro-ph", "hep-ph" ]
M.S. Turner (U. Chicago/Fermilab)
astro-ph/9308017
The large-scale structure in a universe dominated by cold plus hot dark matter
Using numerical simulations, we investigate the large-scale gravitational clustering in a flat universe dominated by cold plus hot dark matter (i.e., $\Omega_0=\ocdm+\ohdm+\obaryon=1$). Primordial density fluctuation spectrum is taken to have the Zel'dovich-Harrison form. Three models are studied, with Model I having $...
1993-08-12
2010-12-09
[ "astro-ph" ]
Y.P. Jing, H.J. Mo, G. Boerner, L.Z. Fang
astro-ph/9308016
Does Dissipation in AGN Disks Couple to the Total Pressure?
Recent work on the transport of angular momentum in accretion disks suggests that the Velikhov-Chandrasekhar instability, in which a large scale magnetic field generates small scale eddys in a shearing environment, may be ultimately responsible for this process. Although there is considerable controversy about the orig...
1993-08-12
2007-05-23
[ "astro-ph" ]
E.T. Vishniac
astro-ph/9308015
A Unique Mass Function from Galaxies to Clusters ?
We present an observational mass function ranging from galaxies to massive galaxy clusters, derived from direct dynamical mass estimates. Our mass function shows, in the low-mass range of galaxies and groups, a behaviour in agreement with that of standard CDM (n=-2), while in the high-mass range (clusters) our mass fun...
1993-08-11
2007-05-23
[ "astro-ph" ]
G.Giuricin, F.Mardirossian, M.Mezzetti, M.Persic, P.Salucci
astro-ph/9308014
Boson Stars in the Brans-Dicke Gravitational Theories
Boson stars consist of a system of self-gravitating scalar fields which form a macroscopic quantum state and are a possible dark matter candidate. In this paper, we address the existence of boson stars in Brans-Dicke gravity. We show that solutions to the equations of motion of a boson star in Brans-Dicke gravity exist...
1993-08-10
2009-10-22
[ "astro-ph", "gr-qc" ]
Mark A. Gunderson and Lars Gerhard Jensen
astro-ph/9308012
Weakly Non-Linear Gaussian Fluctuations and the Edgeworth Expansion
We calculate the cosmological evolution of the 1-point probability distribution function (PDF), using an analytic approximation that combines gravitational perturbation theory with the Edgeworth expansion of the PDF. Our method applies directly to a smoothed mass density field or to the divergence of a smoothed peculia...
1993-08-09
2009-10-22
[ "astro-ph" ]
R. Juszkiewicz, D. Weinberg, P. Amsterdamski, M. Chodorowski & F. Bouchet
astro-ph/9308013
Clustering in the 1.2 Jy IRAS Galaxy Redshift Survey II: Redshift Distortions and \xi(r_p,\pi)
We examine the effect of redshift space distortions on the galaxy two-point correlation function $\xi(r_p,\pi)$ as a function of separations parallel ($r_p$) and perpendicular ($\pi$) to the line of sight. We find that the relative velocity dispersion of pairs of IRAS galaxies is $\sigma(r)= 317^{+40}_{-49}$ \kms at $r...
1993-08-09
2015-06-24
[ "astro-ph" ]
Karl B Fisher, Marc Davis, Michael A Strauss, Amos Yahil, John P Huchra
astro-ph/9308011
On the probability of major-axis precession in triaxial ellipsoidal potentials
Orbits in triaxial ellipsoidal potentials precess about either the major or minor axis of the ellipsoid. In standard perturbation theory it can be shown that a circular orbit will precess about the minor axis if its angular momentum vector lies in a region bounded by two great circles which pass through the intermediat...
1993-08-09
2015-06-24
[ "astro-ph" ]
P. A. Thomas, S. Vine and F. R. Pearce
astro-ph/9308008
Testing the Frozen-Flow Approximation
We investigate the accuracy of the frozen--flow approximation (FFA), recently proposed by Matarrese \etal (1992), for following the nonlinear evolution of cosmological density fluctuations under gravitational instability. We compare a number of statistics between results of the FFA and nbody simulations, including thos...
1993-08-06
2015-06-24
[ "astro-ph" ]
Adrian L. Melott, Francesco Lucchin, Sabino Matarrese and Lauro Moscardini
astro-ph/9308010
Atmospheric Models of Flare Stars: The Quiescent State of Ad Leo
We compute a semi-empirical atmospheric model for the dMe star AD Leo, which constitutes the first model computed to match the continuum observations, as well as a wide set of chromospheric spectral lines. We find good agreement between the computed and observed spectral features, with the exception of the Ca II K line...
1993-08-06
2007-05-23
[ "astro-ph" ]
P. Mauas and A. Falchi
astro-ph/9308009
Our Galactic Center: A laboratory for the feeding of AGNs?
We demonstrate that our Galactic Center, despite little evidence for the presence of a currently active nucleus, provides insight into the feeding of AGN: The observed velocity field of molecular clouds can be interpreted as tracing out the spiralling inwards of gas in a large accretion flow towards the Galactic Center...
1993-08-06
2007-05-23
[ "astro-ph" ]
Susanne von Linden, Peter L. Biermann, Wolfgang J. Duschl, Harald Lesch, and Thomas Schmutzler
astro-ph/9308007
Do Gamma-Ray Burst Sources Repeat
Following the discovery by Quashnock and Lamb (1993) of an apparent excess of $\gamma$-ray burst pairs with small angular separations, we reanalyze the angular distribution of the bursts in the BATSE catalogue. We find that in addition to an excess of close pairs, there is also a comparable excess of antipodal bursts, ...
1993-08-05
2016-06-08
[ "astro-ph" ]
Ramesh Narayan and Tsvi Piran
astro-ph/9308004
Dust-Radiation Universes: Stability Analysis
Flat and open universe models are considered, containing a mixture of cold matter (dust) and radiation interacting only through gravity, with the aim of studying their stability with respect to linear scalar perturbations. To this end the perturbed universe is considered as a dynamical system, described by coupled diff...
1993-08-04
2015-06-24
[ "astro-ph" ]
Marco Bruni and Kamilla Piotrkowska
astro-ph/9308002
Kurtosis and Large--Scale Structure
We discuss the non--linear growth of the excess kurtosis parameter of the smoothed density fluctuation field $\delta$, $S_4\equiv[\lan\delta^{\,4}\ran-3\lan\delta^{\,2}\ran^2]/ \lan\delta^{\,2}\ran^3$ in an Einstein--de Sitter universe. We assume Gaussian primordial density fluctuations with scale--free power spectrum ...
1993-08-04
2009-10-22
[ "astro-ph" ]
Paolo Catelan and Lauro Moscardini
astro-ph/9308005
The Sign of Four: A new class of cool non-radially pulsating stars?
In this paper we discuss four early F-type variable stars whose periods are an order of magnitude slower than known pulsators of comparable luminosity. They cannot be stars undergoing simple radial pulsations. For one or more of these stars we can discount the possibility that the variability is due to rotational modul...
1993-08-04
2007-05-23
[ "astro-ph" ]
Kevin Krisciunas