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astro-ph/9406003
The Companion of M4a: A Planet or a Star?
The $\ddot P$ (Backer 1992, Backer et al. 1993, Thorsett et al. 1993) observed for PSR~B1620-26 in the globular cluster M4 is most likely due to external gravitational jerk from a bound companion. Solving for the $\ddot P$ observed, constrained by the observed $\dot P$, two natural solutions are a jovian mass in a $\gt...
1994-06-01
2007-05-23
[ "astro-ph" ]
Steinn Sigurdsson
astro-ph/9406001
Imprints of Galaxy Clsutering Evolution on Delta T / T
The nonlinear evolution of matter clustering induces temperature anisotropies in the cosmic microwave background. The fluctuations in temperature are produced at a relatively low redshift, $z\simlt 10$, and consequently are not affected by the uncertain reionization proccesses that occurred at earlier epochs. The ampli...
1994-06-01
2009-10-22
[ "astro-ph" ]
Enrique Martinez- Gonzalez, Jose L. Sanz, Joseph Silk
astro-ph/9406002
Compton Scattering in Jets: A Mechanism for $\sim$ 0.4 and $\lsim$ 0.2 Mev Line Production
We show that gamma ray line emission at $\sim$0.4 MeV and $\lsim 0.2$ MeV can be produced by Compton scattering of beamed radiation in the jets of Galactic black hole candidates. This mechanism has the novel feature of not invoking the presence of $e^+$--$e^-$ pairs. To produce the two lines we employ a symmetric doubl...
1994-06-01
2009-10-22
[ "astro-ph" ]
J. G. Skibo, C. D. Dermer and R. Ramaty
astro-ph/9405074
Evolution in the Clustering of Galaxies to r = 26 (TAPIR GRP-390)
We present results for the two-point angular correlation function of galaxies to a limiting magnitude of r=26. The final sample is 97% complete to r=26.0, yielding 5730 galaxies over a 90.1 sq. arcmin field. The correlation function for our faint galaxies can be parameterised by a power law, $A \theta^{-0.8}$, in agree...
1994-05-31
2015-06-24
[ "astro-ph" ]
Tereasa G. Brainerd, Ian Smail, and Jeremy R. Mould
astro-ph/9405070
Observational Support for the Gurzadyan-Kocharyan Relation in Clusters of Galaxies
We show that observational data for four Abell clusters of galaxies support the Gur\-za\-dyan-Kocharyan relation between the Hausdorff dimension and the dynamical properties of a galaxy system. The Hausdorff dimension is calculated using the two-point correlation function, while the dynamical parameters are estimated u...
1994-05-31
2007-05-23
[ "astro-ph" ]
Pierluigi Monaco
astro-ph/9405073
The Primordial Abundance of $^6$Li and $^9$be
Light element ($^6$Li, $^7$Li and $^9$Be) depletion isochrones for halo stars have been calculated with standard stellar evolution models. These models include the latest available opacities and are computed through the sub-giant branch. If $^6$Li is not produced in appreciable amounts by stellar flares, then the detec...
1994-05-31
2009-10-22
[ "astro-ph" ]
Brian Chaboyer
astro-ph/9405071
Ejection of Fragments in Supernova Explosions
Recent observations by the ROSAT X-ray satellite of the Vela supernova remnant have revealed, in addition to the previously identified compact nebula, a nearly circular emitting region with a radius of about 4 degrees. The Vela pulsar is slightly off the center of this circular region, consistent with its measured prop...
1994-05-31
2007-05-23
[ "astro-ph" ]
A. Loeb, F.A. Rasio, and J. Shaham
astro-ph/9405069
The EMSS catalog of X-ray-selected clusters of galaxies. I. An atlas of CCD images of 41 distant clusters
An atlas of deep, wide-field R-band CCD images of a complete sample of distant, X-ray-selected clusters of galaxies is presented. These clusters are the 41 most distant (z>= 0.15) and most X-ray luminous (Lx >= 2x10**44 erg\s-1) clusters in the Einstein Observatory Extended Medium Sensitivity Survey (EMSS) catalog that...
1994-05-31
2008-11-26
[ "astro-ph" ]
I.M. Gioia and G.A. Luppino
astro-ph/9405075
Probing the Large-Scale Velocity Field with Clusters of Galaxies
What is the role of clusters of galaxies in probing the large-scale velocity field of the universe? We investigate the distribution of peculiar velocities of clusters of galaxies in the popular low-density ($\Omega=0.3$) flat Cold-Dark-Matter (CDM) cosmological model, which best fits many large-scale structure observat...
1994-05-31
2009-10-22
[ "astro-ph" ]
Neta A. Bahcall, Renyue Cen and Mirt Gramann (Princeton University Observatory, Princeton, NJ)
astro-ph/9405072
Reionization and the Cosmic Microwave Background
If the COBE detection of CMB fluctuations is used to normalize the power spectrum of primordial density fluctuations in a cold dark matter--dominated universe, early reionization is likely to result in a substantial diminution of primordial temperature fluctuations on degree scales. I argue that the reionization may be...
1994-05-31
2009-10-22
[ "astro-ph" ]
Joseph Silk
astro-ph/9405068
Abundance Analysis and Origin of the Zeta Sculptoris Open Cluster
We have determined chemical abundances and radial velocities for stars in the field of the zeta Sculptoris cluster. We find that the cluster metal deficiency previously found from UBV photometry is too high; the cluster overall metallicity, [Fe/H]=+0.24, is about 70% higher than the solar value. The chemical abundance ...
1994-05-30
2007-05-23
[ "astro-ph" ]
Bengt Edvardsson, Bertil Pettersson, Maryam Kharrazi and Bengt Westerlund
astro-ph/9405067
Hydrodynamics and High-Energy Physics of WR Colliding Winds
One of the main properties of Wolf-Rayet (WR) stars is a very intense outflow of gas. No less than 40\% \ of WR stars belong to binary systems. Young massive O and B stars are the secondary components of such systems. OB stars also have an intense stellar wind. If the intensities of the stellar winds of WR and OB sta...
1994-05-29
2007-05-23
[ "astro-ph" ]
Vladimir V. Usov
astro-ph/9405064
Neutrinos from the Sun: experimental results confronted with solar models
For standard neutrinos, recent solar neutrino results together with the assumption of a nuclearly powered Sun imply severe constraints on the individual components of the total neutrino flux: \Phi_{Be}<0.7*10^9cm^-2 s^-1, \Phi_{CNO}< 0.6*10^9 cm^-2 s^-1, and $64*10^9 cm^-2 s^-1< \Phi_{pp+pep} < 65*10^9 cm^-2 s^-1 (at 1...
1994-05-27
2009-12-30
[ "astro-ph", "hep-ph" ]
Vittorio Castellani, Scilla Degl'innocenti, Gianni Fiorentini, Marcello Lissia and Barbara Ricci
astro-ph/9405066
Accretion Rates in X--Ray Bursting Sources
We present estimates for the accretion rates in 13 X--ray bursting sources which exhibit photospheric expansion, basing on theoretical models of stationary, radiatively driven winds from neutron stars. The relatively high values obtained, $\Mdot_{acc}\magcir 10^{-9} \MS$, are in accordance with theoretical limits for u...
1994-05-27
2009-10-22
[ "astro-ph" ]
Iosif Lapidus, Luciano Nobili and Roberto Turolla
astro-ph/9405065
Winds from Neutron Stars and Strong Type I X--Ray Bursts
A model for stationary, radiatively driven winds from X--ray bursting neutron stars is presented. General relativistic hydrodynamical and radiative transfer equations are integrated from the neutron star surface outwards, taking into account for helium nuclear burning in the inner, dense, nearly hydrostatic shells. Rad...
1994-05-27
2009-10-22
[ "astro-ph" ]
Luciano Nobili, Roberto Turolla and Iosif Lapidus
astro-ph/9405061
Observation of [CI] toward the GL 2591 and W28 A2 Molecular Outflows
Molecular outflows associated with GL 2591 and W28 A2 were observed in the 492 GHz [CI] line. Upper limits are set on the [CI] emission in the extremely high velocity line wings. These limits are discussed in terms of wind-driven and jet-driven models of molecular outflows.
1994-05-26
2009-10-22
[ "astro-ph" ]
Choi, Evans, Jaffe, and Walker
astro-ph/9405062
Detection of Lens Candidates for the Double QSO Q2345+007
Luminous objects associated with the 7.06\arcsec\ separation double quasar Q2345+007 have, until now, escaped detection. In this letter we present the results of the deepest known imaging of the region surrounding the quasar. The total exposure times were 47600 seconds in B$_j$ (101 frames) and 32160 seconds in R (82 f...
1994-05-26
2009-10-22
[ "astro-ph" ]
Philippe Fischer, J. Anthony Tyson, Gary M. Bernstein, and Puragra Guhathakurta
astro-ph/9405060
The Casimir Effect as a Possible Source of Cosmic Energy
Energy production due to the Casimir effect is considered for the case of a superdense state of matter, which can appear in such cosmological objects as white dwarfs, neutron stars, quasars and so on. The energy output produced by the Casimir effect during the creation of a neutron star turns out to be sufficient to ex...
1994-05-26
2008-02-03
[ "astro-ph" ]
Igor Yu.Sokolov
astro-ph/9405057
Probability Distribution of Primordial Angular Momentum and Formation of Massive Black Holes
We consider the joint probability distribution function for the mass contrast and angular momentum of over-density regions on the proto- galactic scale and investigate the formation of massive black holes at redshift $z\gsim10$. We estimate the growth rate of the angular momentum by the linear perturbation theory and t...
1994-05-26
2009-10-09
[ "astro-ph" ]
Hajime Susa, Misao Sasaki, and Takahiro Tanaka
astro-ph/9405058
Pre-Collapse Evolution of Galactic Globular Clusters
This paper is concerned with collisionless aspects of the early evolution of model star clusters. The effects of mass loss through stellar evolution and of a steady tidal field are modelled using $N$-body simulations. Our results (which depend on the assumed initial structure and the mass spectrum) agree qualitatively ...
1994-05-26
2015-06-24
[ "astro-ph" ]
Toshiyuki Fukushige and Douglas C. Heggie
astro-ph/9405059
A Model for the X-Ray and UV Emission from Seyfert Galaxies and Galactic Black Holes
We propose that the X--ray emission from radio quiet AGN and galactic black holes is due to Comptonization of soft thermal photons emitted by the underlying accretion disk in localized structures (blobs). The power per unit area produced by the blobs, impinging on the disk, can easily dominate the radiation internally ...
1994-05-26
2009-10-22
[ "astro-ph" ]
Francesco Haardt, Laura Maraschi and Gabriele Ghisellini
astro-ph/9405056
How well should the DENIS Survey probe through the Galactic Plane?
The DENIS 2 micron survey is described. It's ability to probe galaxies at very low galactic latitudes is computed using simulated images. This analysis indicates that DENIS will be able to separate galaxies from stars, right through the Galactic Plane, for galactic longitudes $45^\circ \leq \ell \leq 315^\circ$, with a...
1994-05-26
2007-05-23
[ "astro-ph" ]
Gary A. Mamon
astro-ph/9405063
Gravitational Lensing in Clusters of Galaxies: New Clues Regarding the Dynamics of Intracluster Gas
Long arcs in clusters of galaxies, produced by gravitational lensing, can be used to estimate the mass interior to the arcs and therefore, constrain the cluster mass distribution. The radial density distribution of the intracluster gas (ICM) can be extracted from the X-ray surface brightness observations. If the gas te...
1994-05-26
2008-11-26
[ "astro-ph" ]
Jordi Miralda-Escude and Arif Babul
astro-ph/9405055
On Thermal Comptonization in e+- Pair Plasmas
We study $e^{\pm}$ pair plasmas in pair equilibrium, which emit high energy radiation by thermal Comptonization of soft photons. We find that the maximum luminosity to size ratio of the source (i.e. the compactness) depends not only on the hot plasma temperature, but also on the spectral index of the resulting Comptoni...
1994-05-25
2009-10-22
[ "astro-ph" ]
Gabriele Ghisellini and Francesco Haardt
astro-ph/9405054
The Evolutionary Unified Scheme. I. Quasars and Radio Galaxies in the Viewing Angle - Redshift Plane
We present a study of the distribution of quasars and radio galaxies in the plane (viewing angle - redshift) in the framework of the evolutionary unified scheme (Vagnetti et al. 1991). Results are presented for some illustrative cases, including a distribution of the Lorentz factors, and appropriate luminosity function...
1994-05-25
2009-10-22
[ "astro-ph" ]
F. Vagnetti & R. Spera
astro-ph/9405052
On the Influence of X-Ray Galaxy Clusters in the Fluctuations of the Cosmic Microwave Background
The negative evolution found in X--ray clusters of galaxies limits the amount of available hot gas for the inverse Compton scattering of the Cosmic Microwave Background (the Sunyaev--Zel'dovich effect). Using a parametrisation of the X-ray luminosity function and its evolution in terms of a coalescence model (as presen...
1994-05-24
2015-06-24
[ "astro-ph" ]
M.T. Ceballos, X. Barcons
astro-ph/9405050
The Principle of Least Action and Clustering in Cosmology
A scheme is developed which enables one to trace backwards in time the cosmic density and velocity fields, and to determine accurately the current-epoch velocity field from the current-epoch density field, or vice versa. The scheme implements the idea of Giavalisco \etal\ (1993) that the principle of least action shoul...
1994-05-24
2015-06-24
[ "astro-ph" ]
Mikel Susperregi and James Binney
astro-ph/9405051
Orbital Evolution of a Massive Black Hole Pair by Dynamical Friction
We investigate the evolution of a massive black hole pair under the action of dynamical friction (DF) by a uniform background of light stars with isotropic velocity distribution. In our scenario, the primary black hole $M_1$ sits, at rest, in the center of the spherical star distribution (with mass $M_c$) and the secon...
1994-05-24
2009-10-22
[ "astro-ph" ]
A. Vecchio, M. Colpi and A. Polnarev
astro-ph/9405053
Flare Production of $^6$Li in Population~II Stars
Motivated by the recent report of a $^6$Li detection in the atmosphere of HD~84937, we couple stellar evolution calculations with light isotope production via stellar flares. We find that as a consequence of their small convective envelope mass near the turn-off point, low-metallicity dwarfs and subgiants may possess o...
1994-05-24
2009-10-22
[ "astro-ph" ]
C.P. Deliyannis, and R.A. Malaney
astro-ph/9405048
The gasdynamic evolution of spherical planetary nebulae: Radiation-gasdynamics of PNe III
Using a radiation-gasdynamics code the evolution of spherical planetary nebulae is followed, while taking into account the evolution of central star and the fast wind. These models show the importance of ionization fronts for the structure of planetary nebulae, especially for the so called multiple shell nebulae (MSPNe...
1994-05-20
2007-05-23
[ "astro-ph" ]
Garrelt Mellema
astro-ph/9405046
The Radio Emission from the Ultra-Luminous Far-Infrared Galaxy NGC 6240
We present new radio observations of the ``prototypical'' ultra-luminous far- infrared galaxy NGC~6240, obtained using the VLA at 20~cm in `B' configuration and at 3.6~cm in `A' configuration. These data, along with those from four previous VLA observations, are used to perform a comprehensive study of the radio emissi...
1994-05-19
2011-03-10
[ "astro-ph" ]
Edward J. M. Colbert, Andrew S. Wilson and Jonathan Bland-Hawthorn
astro-ph/9405045
A Coupling of Pseudo Nambu Goldstone Bosons to Other Scalars and Role in Double Field Inflation
We find a coupling of Pseudo Nambu Goldstone bosons (PNGBs) to other (ordinary) scalars, and consider its importance in various contexts. Our original motivation was the model of Double Field inflation [1]. We also briefly consider the role of this coupling for the case of the QCD axion.
1994-05-19
2009-10-22
[ "astro-ph" ]
Katherine Freese
astro-ph/9405047
Recalibration of the H$_{\bf -0.5}$ Magnitudes of Spiral Galaxies
The H magnitude aperture data published by the Aaronson et al. collaboration over a 10-year period is collected into a homogeneous data set of 1731 observations of 665 galaxies. 96\% of these galaxies have isophotal diameters and axial ratios determined by the Third Reference Catalogue of Bright Galaxies (de Vaucouleur...
1994-05-19
2009-10-22
[ "astro-ph" ]
G. Tormen (University of Padova) and D. Burstein (Arizona State University)
astro-ph/9405043
Cosmological Evolution of Scale-invariant Gravity Waves
The evolution of scale-invariant gravity waves from the early universe is analyzed using an equation of state which smoothly interpolates between the radiation dominated era and the present matter dominated era. We find that for large wavenumbers the standard scale-invarant wavefunction for the gravity wave severely {\...
1994-05-18
2009-10-22
[ "astro-ph", "gr-qc" ]
K.-W. Ng and A. D. Speliotopoulos
astro-ph/9405044
Polynomial Hybrid Inflation
We study a simple extension of Linde's hybrid inflation model, with the inflaton mass term replaced by the most general renormalizable potential for $\phi$. The unprocessed power spectrum of density perturbations can have two minima and one maximum, roughly corresponding to two steep regions separated by a somewhat fla...
1994-05-18
2009-10-22
[ "astro-ph", "hep-ph" ]
Yun Wang
astro-ph/9405040
Solar nuclear energy generation and the chlorine solar neutrino experiment
The study of solar neutrinos may provide important insights into the physics of the central region of the Sun. Four solar neutrino experiments have confirmed the solar neutrino problem but do not clearly indicate whether solar physics, nuclear physics, or neutrino physics have to be improved to solve it. Nonlinear rela...
1994-05-18
2009-10-22
[ "astro-ph", "hep-ph" ]
H.J. Haubold and A.M. Mathai
astro-ph/9405041
Is the halo responsible for the microlensing events?
We discuss whether the astrophysical objects responsible for the recently reported microlensing events of sources in the Large Magellanic Cloud can be identified as the brown dwarf components of the spheroid of our galaxy, rather than the constituents of a dark baryonic halo.
1994-05-17
2007-05-23
[ "astro-ph" ]
E. Roulet, S. Mollerach and G. F. Giudice
astro-ph/9405042
Reionization in an open cdm universe: implications for cosmic microwave background fluctuations
We generalize previous work on early photoionization to CDM models with Omega<1. Such models have received recent interest because the excess power in the large-scale galaxy distribution is phenomenologically fit if the ``shape parameter" Gamma=h Omega_0 is about 0.25. It has been argued that such models may require ea...
1994-05-17
2009-10-07
[ "astro-ph" ]
Max Tegmark, Joseph Silk
astro-ph/9405039
Ultraluminous Starbursts in Major Mergers
We use numerical simulation to investigate the triggering of starbursts in merging disk galaxies. The properties of the merger-driven starbursts are sensitive to the structure of the progenitor galaxies; specifically, to the amount of material in a dense central bulge. Galaxies without bulges develop bars shortly after...
1994-05-16
2007-05-23
[ "astro-ph" ]
Chris Mihos and Lars Hernquist
astro-ph/9405037
Analytic Expression of the Genus in Weakly Non-Gaussian Field Induced by Gravity
The gravitational evolution of the genus of the density field in large-scale structure is analytically studied in a weakly nonlinear regime using second-order perturbation theory. Weakly nonlinear evolution produces asymmetry in the symmetric genus curve for Gaussian initial density field. The effect of smoothing the d...
1994-05-16
2009-10-22
[ "astro-ph" ]
T. Matsubara
astro-ph/9405038
Cosmic Deuterium Or A Hydrogen Interloper ?
Two groups have independently reported the possible detection of extragalactic deuterium in the absorption spectrum of the same high redshift, low metalicity QSO. Although the high value for the inferred deuterium abundance poses no problems for cosmology (i.e., big bang nucleosynthesis), it is in apparent conflict wit...
1994-05-16
2016-06-08
[ "astro-ph" ]
Gary Steigman
astro-ph/9405036
Massive Tau Neutrino and SN 1987a
The emission of $\MeV$-mass tau neutrinos from newly formed neutron stars is considered in a simple, but accurate, model based upon the diffusion approximation. The tau-neutrinosphere temperature is found to increase with mass so that emission of massive tau neutrinos is not suppressed by the Boltzmann factor previousl...
1994-05-15
2009-09-25
[ "astro-ph", "hep-ph" ]
G. Sigl and M.S. Turner
astro-ph/9405034
Inflationary Perturbations and Exponential Potentials
We consider the spectrum of primordial fluctuations produced by inflationary models where the inflaton potential is the sum of two exponential terms. A wide range of spectra result, with the only constraint being that the scalar spectrum must have more tilt than the tensor spectrum. This model can mimic the spectra of ...
1994-05-15
2009-09-25
[ "astro-ph" ]
Richard Easther
astro-ph/9405035
Multiple Outflow Episodes from Protostars:3-D Models of Intermittent Jets
Short abstract: We present fully 3-D simulations of supersonic, radiatively cooling intermittent jets with intermediate and long variability periods (that is, periods of the order of or longer than, the dynamical time scale of the jet). Variations of intermediate period elucidate the formation and evolution of chains o...
1994-05-15
2009-10-22
[ "astro-ph" ]
E.M. de Gouveia Dal Pino and W. Benz
astro-ph/9405032
Low-frequency gravitational waves from supermassive black holes
Supermassive black holes are investigated as possible sources for low-frequency bursts of gravity waves. The event rate for `known' supermassive black holes at intermediate and high redshifts, inferred from the quasar luminosity function, is low $\sim 0.1 \yr^{-1}$. A space-based interferometer could therefore only see...
1994-05-13
2015-06-24
[ "astro-ph" ]
M. G. Haehnelt
astro-ph/9405033
Delayed Hard Photons from Gamma-Ray Bursts
The delayed hard (up to 25 GeV) photons observed more than an hour following a gamma-ray burst on February 17, 1994 may result from the collisions of relativistic nucleons with a dense cloud, producing $\pi^0$. The required cloud density is $\sim 2 \times 10^{11}$ cm$^{-3}$. This cloud may be the remains of the disrupt...
1994-05-13
2009-10-22
[ "astro-ph" ]
J. I. Katz
astro-ph/9405028
Anharmonic Evolution of the Cosmic Axion Density Spectrum
We present analytic solutions to the spatially homogeneous axion field equation, using a model potential which strongly resembles the standard anharmonic $(1-\cos N\theta)$ potential, but contains only a piece-wise second order term. Our exactly soluble model for $\theta(t)$ spans the entire range $[-\pi/N,\pi/N]$. In ...
1994-05-12
2009-10-22
[ "astro-ph", "hep-ph" ]
K. Strobl, T. J. Weiler
astro-ph/9405027
Black Hole Relics and Inflation: Limits on Blue Perturbation Spectra
Blue primordial power spectra have spectral index $n>1$ and arise naturally in the recently proposed hybrid inflationary scenario. An observational upper limit on {\em n} is derived by normalizing the spectrum at the quadrupole scale and considering the possible overproduction of Planck mass relics formed in the final ...
1994-05-12
2009-09-25
[ "astro-ph", "gr-qc" ]
Bernard J. Carr, Jonathan H. Gilbert & James E. Lidsey
astro-ph/9405030
Ultraviolet Radiation from Evolved Stellar Populations: II. The Ultraviolet Upturn Phenomenon in Elliptical Galaxies
We present an analysis of the far-ultraviolet upturn phenomenon (UVX) observed in elliptical galaxies and spiral galaxy bulges. Our premise is that the UV radiation from these systems emanates primarily from extreme horizontal branch (EHB) stars and their progeny. We re-derive the broad-band UV colors $1500-V$ and $250...
1994-05-12
2009-10-22
[ "astro-ph" ]
Ben Dorman, Robert W. O'Connell, and Robert T. Rood
astro-ph/9405026
Optimal Reconstruction of the Velocity and Density Field: Potent and Max-Flow Algorithms
Although Potent purports to use only radial velocities in reconstructing the potential velocity field of galaxies, the derivation of transverse components is implicit in the smoothing procedures adopted. Thus the possibility arises of using nonradial line integrals to derive a smoothed velocity field. For an inhomogene...
1994-05-12
2007-05-23
[ "astro-ph" ]
J.F.L. Simmons, A. Newsam, M.A. Hendry
astro-ph/9405029
Induced-gravity Inflation and the Density Perturbation Spectrum
Recent experimental determinations of the spectral index describing the scalar mode spectrum of density perturbations encourage comparison with predictions from models of the very early universe. Unlike extended inflation, Induced-gravity Inflation predicts a power spectrum with $0.98 \leq n_s \leq 1.00$, in close agre...
1994-05-12
2009-10-22
[ "astro-ph", "gr-qc" ]
David Kaiser
astro-ph/9405031
The X-ray Spectrum of Soft Gamma Repeater 1806-20
Soft Gamma Repeaters (SGRs) are a class of rare, high-energy galactic transients that have episodes of short (~0.1 sec), soft (~30 keV), intense (~100 Crab), gamma-ray bursts. We report an analysis of the x-ray emission from 95 SGR1806-20 events observed by the International Cometary Explorer. The spectral shape remain...
1994-05-12
2009-10-22
[ "astro-ph" ]
E.E. Fenimore, J.G. Laros, A. Ulmer
astro-ph/9405022
On the Abundance of Primordial Helium
We have used recent observations of helium-4, nitrogen and oxygen from some four dozen, low metallicity, extra-galactic HII regions to define mean $N$ versus $O$, $^4He$ versus $N$ and $^4He$ versus $O$ relations which are extrapolated to zero metallicity to determine the primordial $^4He$ mass fraction $Y_P$. The data...
1994-05-11
2009-09-25
[ "astro-ph" ]
Keith A. Olive and Gary Steigman
astro-ph/9405024
Microwave background anisotropy in low-$\Omega_0$ inflationary models and the scale of homogeneity in the Universe
We study the microwave background anisotropy due to superhorizon-size perturbations (the Grischuk-Zel'dovich effect) in open universes with negative spatial curvature. Using COBE results on the low-order temperature multipole moments, we find that if the homogeneity of the observable Universe arises from an early epoch...
1994-05-11
2009-10-22
[ "astro-ph" ]
A. Kashlinsky, I. I. Tkachev, and J. Frieman
astro-ph/9405023
HST Observations of Gravitationally Lensed Features in the Rich Cluster Ac114
Deep Hubble Space Telescope images of superlative resolution obtained for the distant rich cluster AC114 (z=0.31) reveal a variety of gravitational lensing phenomena for which ground-based spectroscopy is available. We present a luminous arc which is clearly resolved by HST and appears to be a lensed z=0.64 sub-L star ...
1994-05-11
2009-10-22
[ "astro-ph" ]
Ian Smail, Warrick J. Couch, Richard S. Ellis & Ray M. Sharples
astro-ph/9405025
Cosmic Ray Models for Early Galactic Lithium, Beryllium, and Boron Production
To understand better the early galactic production of Li, Be, and B by cosmic ray spallation and fusion reactions, the dependence of these production rates on cosmic ray models and model parameters is examined. The sensitivity of elemental and isotopic production to the cosmic ray pathlength magnitude and energy depend...
1994-05-11
2009-09-25
[ "astro-ph" ]
Brian Fields, Keith Olive, and David Schramm
astro-ph/9405021
Beyond the Thin Lens Approximation
We obtain analytic formulae for the null geodesics of Friedmann-Lema\^{\i}tre-Robertson-Walker spacetimes with scalar perturbations in the longitudinal gauge. We use these to provide a rigorous derivation of the cosmological lens equation. We obtain an expression for the magnification of a bundle of light rays in these...
1994-05-10
2007-05-23
[ "astro-ph", "gr-qc" ]
Ted Pyne and Mark Birkinshaw
astro-ph/9405020
Implications of Particle Acceleration in Active Galactic Nuclei for Cosmic Rays and High Energy Neutrino Astronomy
We consider the production of high energy neutrinos and cosmic rays in radio-quiet active galactic nuclei (AGN) or in the central regions of radio-loud AGN. We use a model in which acceleration of protons takes place at a shock in an accretion flow onto a supermassive black hole, and follow the cascade that results fro...
1994-05-10
2010-11-30
[ "astro-ph" ]
A.P. Szabo and R.J. Protheroe
astro-ph/9405018
Solar Neutrinos Almost Independently of Solar Models
Recent solar neutrino results together with the assumption of a stationary Sun imply severe constraints on the individual components of the total neutrino flux : $\Phi_{Be} \leq 0.7 \cdot 10^{9} cm^{-2} s^{-1}, \Phi_{CNO} \leq 0.6 \cdot 10^{9} cm^{-2} s^{-1}$ and $64 \cdot 10^{9} cm^{-2} s^{-1} \leq \Phi_{pp+pep} \leq ...
1994-05-09
2009-09-25
[ "astro-ph" ]
V.Castellani, S. Degl'Innocenti, G.Fiorentini, B.Ricci
astro-ph/9405017
Testing the Least Action Principle in an Omega_0=1 Universe
The least action principle (LAP) is a dynamically rigorous method for deriving the history of galaxy orbits. In particular it is an Omega_0 test, predicting current epoch galaxy velocities as a function of position and of the cosmological background. It is most usefully applied to in--falling structures, such as the lo...
1994-05-09
2009-10-22
[ "astro-ph" ]
E.Branchini and R.G.Carlberg
astro-ph/9405019
Fragmentation of a Magnetized Filamentary Molecular Cloud Rotating around its Axis
The dynamical instability of a self-gravitating magnetized filamentary cloud was investigated while taking account of rotation around its axis. The filamentary cloud of our model is supported against self-gravity in part by both a magnetic field and rotation. The density distribution in equilibrium was assumed to be a ...
1994-05-09
2007-05-23
[ "astro-ph" ]
Tomoaki Matsumoto, Fumitaka Nakamura, and Tomoyuki Hanawa
astro-ph/9405015
Gravitational Lens Time Delays and Gravitational Waves
Using Fermat's principle, we analyze the effects of very long wavelength gravitational waves upon the images of a gravitationally lensed quasar. We show that the lens equation in the presence of gravity waves is equivalent to that of a lens with different alignment between source, deflector, and observer in the absence...
1994-05-06
2011-09-09
[ "astro-ph", "gr-qc" ]
J. Frieman, D. Harari, and G. Surpi
astro-ph/9405013
The Cosmic X-ray Background -- IRAS galaxy Correlation and the Local X-ray Volume Emissivity
We have cross-correlated the galaxies from the IRAS 2 Jy redshift survey sample and the 0.7 Jy projected sample with the all-sky cosmic X-ray background (CXB) map obtained from the HEAO-1 A2 experiment. We have developed a formulation to model the cross-correlation between CXB surface brightness and galaxy counts. This...
1994-05-05
2009-10-22
[ "astro-ph" ]
Takamitsu Miyaji, Ofer Lahav, Keith Jahoda, Elihu Boldt
astro-ph/9405012
An Analytical Model for the Triaxial Collapse of Cosmological Perturbations
We present an analytical model for the non-spherical collapse of overdense regions out of a Gaussian random field of initial cosmological perturbations. The collapsing region is treated as an ellipsoid of constant density, acted upon by the quadrupole tidal shear from the surrounding matter. The dynamics of the ellipso...
1994-05-05
2009-10-22
[ "astro-ph" ]
Daniel J. Eisenstein and Abraham Loeb
astro-ph/9405016
Accretion Disk Coronae in High Luminosity Systems
We present the results of self-consistent models of Compton-heated accretion disk coronae. The models are calculated using a new method for computing monochromatic radiative transfer in two-dimensions. The method splits the radiation into direct and scattered components. The direct radiation is computed by calculating ...
1994-05-05
2009-10-22
[ "astro-ph" ]
Stephen D. Murray, John I. Castor, Richard I. Klein, and Christopher F. McKee
astro-ph/9405014
Galaxy Mergers and Gravitational Lens Statistics
We investigate the impact of hierarchical galaxy merging on the statistics of gravitational lensing of distant sources. Since no definite theoretical predictions for the merging history of luminous galaxies exist, we adopt a parametrized prescription, which allows us to adjust the expected number of pieces comprising a...
1994-05-05
2019-08-17
[ "astro-ph" ]
Hans-Walter Rix, Dan Maoz, Edwin L. Turner and Masataka Fukugita
astro-ph/9405011
Velocity Differences as a Probe of Non--Gaussian Density Fields
We examine the multi--point velocity field for non--Gaussian models as a probe of non--Gaussian behavior. The two--point velocity correlation is not a useful indicator of a non--Gaussian density field, since it depends only on the power spectrum, even for non--Gaussian models. However, we show that the distribution of ...
1994-05-04
2009-10-22
[ "astro-ph" ]
Paolo Catelan and Robert J. Scherrer
astro-ph/9405009
BATSE Gamma-Ray Burst Line Search: II. Bayesian Consistency Methodology
We describe a Bayesian methodology to evaluate the consistency between the reported Ginga and BATSE detections of absorption features in gamma ray burst spectra. Currently no features have been detected by BATSE, but this methodology will still be applicable if and when such features are discovered. The Bayesian method...
1994-05-03
2009-10-22
[ "astro-ph" ]
D. L. Band, L. A. Ford, J. L. Matteson, M. Briggs, W. Paciesas, G. Pendleton, R. Preece, D. Palmer, B. Teegarden, and B. Schaefer
astro-ph/9405008
Neutrino Flavor Evolution Near a Supernova's Core
(The discussion is expanded, and a mistake in the crossing probability is corrected.)
1994-05-03
2011-07-19
[ "astro-ph", "hep-ph" ]
J. Pantaleone
astro-ph/9405007
G272.2--3.2: A centrally filled and possibly young SNR discovered by ROSAT
We report the discovery of a new SNR in the \ros All-Sky-Survey data. The SNR has a nearly circular shape with a diameter of about 15 arcmin. The surface brightness is rather uniform over the remnant. The observed interstellar absorption suggests a distance of about 1.8$^{+1.4}_{-0.8}$ kpc. The X-ray emission appears t...
1994-05-03
2007-05-23
[ "astro-ph" ]
J. Greiner, R. Egger, B. Aschenbach
astro-ph/9405010
Baryonic Dark Matter and Big-Bang Nucleosynthesis
The enclosed paper was submitted for publication in Ap.J Lett. in February 1992. It has been rejected on the grounds that it predicts primordial Deuterium abundance which is contradicted by observations and because it disagreed with published analysis and conclusions of previous authors. However, in a recent article in...
1994-05-03
2007-05-23
[ "astro-ph" ]
Arnon Dar, Jaques Goldberg and Michael Rudzsky
astro-ph/9405006
$\gamma$-Ray Bursts and Neutron Star Mergers
$\gamma$-ray bursts have baffled theorists ever since their accidental discovery at the sixties. We suggest that these bursts originate in merger of neutron star binaries, taking place at cosmological distances. These mergers release $\approx 10^{54}ergs$, in what are possibly the strongest explosions in the Universe. ...
1994-05-03
2007-05-23
[ "astro-ph" ]
Tsvi Piran
astro-ph/9405005
Competition between Pressure and Gravity Confinement in Lyman-Alpha Forest Observations
A break in the distribution function of Ly$\alpha$ clouds (at a typical redshift of $2.5$) has been reported by Petitjean et al. (1993). This feature is what would be expected from a transition between pressure confinement and gravity confinement (as predicted in Charlton, Salpeter, and Hogan (1993)). The column densit...
1994-05-03
2009-10-22
[ "astro-ph" ]
Jane C. Charlton, Edwin E. Salpeter, and Suzanne M. Linder
astro-ph/9405002
Large Scale Structure Effects on the Gravitational Lens Image Positions and Time Delay
We compute the fluctuations in gravitational lens image positions and time delay caused by large scale structure correlations. We show that these fluctuations can be expressed as a simple integral over the density power spectrum. Using the {\sl COBE} normalization we find that positions of objects at cosmological dista...
1994-05-02
2008-11-26
[ "astro-ph" ]
Uros Seljak
astro-ph/9405004
Recent Deuterium Observations and Big Bang Nucleosynthesis: A New Paradigm?
A new observation of D in a primordial gas cloud, made using the high resolution spectrograph at the Keck telescope, indicates an abundance $ D/H =(1.9-2.5) \times 10^{-4}$ \cite{SCHR}. Since deuterium is destroyed by stars, and the predicted Big Bang Nucleosynthesis (BBN) abundance falls monotonically with increasing ...
1994-05-02
2009-10-22
[ "astro-ph", "hep-ph" ]
Lawrence M. Krauss and Peter J. Kernan
astro-ph/9405003
Damped Lyman Alpha Systems vs. Cold + Hot Dark Matter
Although the Cold + Hot Dark Matter (CHDM) cosmology provides perhaps the best fit of any model to all the available data at the current epoch, CHDM produces structure at relatively low redshifts and thus could be ruled out if there were evidence for formation of massive objects at high redshifts. Damped Ly$\alpha$ sys...
1994-05-02
2009-10-22
[ "astro-ph", "hep-ph" ]
Anatoly Klypin, Stefano Borgani, Jon Holtzman, & Joel Primack
astro-ph/9405001
Deviations from Hierarchical Clustering in Real and Redshift Space
We discuss the effects of redshift--space distortions on the estimate of high order galaxy correlation functions. We use both the Perseus--Pisces redshift survey and the results of high--resolution N--body simulations to explore the consequences of working in redshift space on the detection of deviations from hierarchi...
1994-05-02
2007-05-23
[ "astro-ph" ]
S. Ghigna, S.A. Bonometto, L. Guzzo, R. Giovanelli, M.P. Haynes, A.Klypin & J.R. Primack
astro-ph/9404080
Compact Radio Cores in Seyfert Galaxies
We have observed a sample of 157 Seyfert galaxies with a 275 km baseline radio interferometer to search for compact, high brightness temperature radio emission from the active nucleus. We obtain the surprising result that compact radio cores are much more common in Seyfert 2 than in Seyfert 1 galaxies, which at first s...
1994-04-30
2009-10-22
[ "astro-ph" ]
A. L. Roy, R. P. Norris, M. J. Kesteven, E. R. Troup, & J. E. Reynolds
astro-ph/9404078
Quasar Production:Topological Defect Formation due to a Phase Transition linked with Massive Neutrinos
Recent observations of the space distribution of quasars indicate a very notable peak in space density at a redshift of $2$ to $3$.It is pointed out in this article that this may be the result of a phase transition which has a critical temperature of roughly a few meV (in the cosmological units h=c=k=1 ). It is further...
1994-04-29
2010-11-01
[ "astro-ph", "gr-qc", "hep-ph" ]
Anupam Singh
astro-ph/9404079
Diffuse Gamma Rays from WIMP Decay and Annihilation
I discuss contributions to the diffuse gamma-ray background from decay and annihilation of weakly interacting massive particles (WIMPs). I first review the calculation of the cosmological abundance of a WIMP and show that it is simply related to the cross section for annihilation of the WIMP into lighter particles. The...
1994-04-29
2007-05-23
[ "astro-ph", "hep-ph" ]
Marc Kamionkowski
astro-ph/9404073
The Evolution and Efficiency of Oblique MHD Cosmic-Ray Shocks: Two-Fluid Simulations
Using a new, second-order accurate numerical method we present dynamical simulations of oblique MHD cosmic ray (CR) modified plane shock evolution using the two-fluid model for diffusive particle acceleration. The numerical shocks evolve to published analytical steady state properties. In order to probe the dynamical r...
1994-04-29
2009-10-22
[ "astro-ph" ]
Adam Frank, T. W. Jones, and Dongsu Ryu
astro-ph/9404077
From the Owl to the Eskimo: the Radiation-Gasdynamics of Planetary Nebulae IV
We present the results of two-dimensional radiation-gasdynamic simulations of aspherical Planetary Nebulae (PNe) evolution. These simulations were constructed using the Generalized Interacting Stellar Winds (GISW) scenario of Balick (1987) where a fast, tenuous wind from the central star expands into a toroidal, slow, ...
1994-04-29
2018-07-25
[ "astro-ph" ]
Adam Frank and Garrelt Mellema
astro-ph/9404076
On Fractal Structure of Quantum Gravity and Relic Radiation Anisotropy
It is argued that large-scale ($>7^o$) cosmic microwave background anisotropy detected in COBE cosmic experiment can be considered as a trace of the quantum gravity fractal structure.
1994-04-29
2008-02-03
[ "astro-ph", "hep-ph" ]
M.V. Altaisky, V.A. Bednyakov and S.G. Kovalenko
astro-ph/9404074
Numerical Magnetohydrodynamics in Astrophysics: Algorithm and Tests for One-Dimensional Flow
We describe a numerical code to solve the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit finite difference scheme on an Eulerian grid, called the Total Variation Diminishing (TVD) scheme, which is a second-order-accurate extension of the Roe-type upwind scheme. We also describe a nonlinear R...
1994-04-29
2009-10-22
[ "astro-ph" ]
Dongsu Ryu and T. W. Jones
astro-ph/9404071
The effect of triplet production on pair-Compton cascades in thermal radiation
We calculate the spectrum of photons resulting from electromagnetic cascades through thermal radiation, and examine the consequences of including triplet production in these cascades. We assume that the cascade is one-dimensional, and we find that this approximation is justified in the present work for thermal radiatio...
1994-04-28
2015-06-24
[ "astro-ph" ]
A. Mastichiadis, R.J. Protheroe and A.P. Szabo
astro-ph/9404075
Bloated Stars as AGN Broad Line Clouds: The Emission Line Spectrum
The Bloated Stars Scenario proposes that AGN broad line emission originates in the winds or envelopes of bloated stars (BS). Its main advantage over BLR cloud models is the gravitational confinement of the gas and its major difficulty the large estimated number of BSs and resulting high mass loss rate. We calculate the...
1994-04-28
2015-06-24
[ "astro-ph" ]
Tal Alexander and Hagai Netzer
astro-ph/9404072
Measurements of Anisotropy in the Cosmic Microwave Background Radiation at Degree Angular Scales Near the Stars Sigma Hercules and Iota Draconis
We present results from two four-frequency observations centered near the stars Sigma Hercules and Iota Draconis during the fourth flight of the Millimeter-wave Anisotropy eXperiment (MAX). The observations were made of 6 x 0.6-degree strips of the sky with 1.4-degree peak to peak sinusoidal chop in all bands. The FWHM...
1994-04-28
2008-02-03
[ "astro-ph" ]
A. C. Clapp, M. J. Devlin, J. O. Gundersen, C. A. Hagmann, V. V. Hristov, A.E. Lange, M. Lim, P. M. Lubin, P. D. Mauskopf, P. R. Meinhold, P. L. Richards, G. F. Smoot, S. T. Tanaka P. T. Timbie, and C. A. Wuensche
astro-ph/9404068
CBR anisotropy from primordial gravitational waves in inflationary cosmologies
We examine stochastic temperature fluctuations of the cosmic background radiation (CBR) arising via the Sachs-Wolfe effect from gravitational wave perturbations produced in the early universe. These temperature fluctuations are described by an angular correlation function $C(\gamma)$. A new (more concise and general) d...
1994-04-27
2009-10-22
[ "astro-ph", "gr-qc" ]
Bruce Allen and Scott Koranda
astro-ph/9404067
A Potential Window to the GUT
The possibility that the form of the inflationary potential can be reconstructed from a knowledge of the primordial power spectra of scalar (density) and tensor (gravity wave) perturbations is discussed and reviewed. It is suggested that measurements of the scalar spectral index and the amplitude of the tensor spectrum...
1994-04-27
2007-05-23
[ "astro-ph" ]
James E. Lidsey
astro-ph/9404069
Sample Variance of non-Gaussian Sky Distributions
Non-Gaussian distributions of cosmic microwave background (CMB) anisotropies have been proposed to reconcile the discrepancies between different experiments at half-degree scales (Coulson et al. 1994). Each experiment probes a different part of the sky, furthermore, sky coverage is very small, hence the sample variance...
1994-04-27
2009-10-22
[ "astro-ph" ]
Xiaochun Luo
astro-ph/9404070
Solar Neutrinos: Where We Are, Where We Are Going
There are four important facts about solar neutrinos. They are listed in order of importance in this abstract and discussed more in the text of the talk. First, solar neutrinos have been detected in four experiments with approximately the energies and fluxes predicted by the standard solar model, confirming the hypothe...
1994-04-27
2008-02-03
[ "astro-ph" ]
John N. Bahcall
astro-ph/9404066
Abundance Gradients in Cooling Flow Clusters: Ginga Lac & Einstein SSS Spectra of A496, A1795, A2142 & A2199
We analyze the Ginga LAC and Einstein SSS spectra of four cooling flow clusters, A496, A1795, A2142 and A2199, each of which shows firm evidence of a relatively cool component. The inclusion of such cool spectral components in joint fits of SSS and LAC data leads to somewhat higher global temperatures than are derived ...
1994-04-26
2007-05-23
[ "astro-ph" ]
Raymond E. White III, C. S. R. Day, Isamu Hatsukade and John P. Hughes
astro-ph/9404065
The Hidden Nuclear Spectrum of the Luminous IRAS Source FSC10214$+$4724
Optical spectropolarimetry of the luminous IRAS source FSC10214$+$4724 (z$=2.286$) reveals that the strong (\twid17\%) linear polarization detected by Lawrence \etal\/ is shared by both the narrow UV emission lines and the underlying continuum. This observation and the brightness of the source rule out synchrotron emis...
1994-04-26
2009-10-22
[ "astro-ph" ]
Buell T. Jannuzi, Richard Elston, Gary D. Schmidt, Paul S. Smith, and H. S. Stockman
astro-ph/9404062
Resonant Oscillations and Tidal Heating in Coalescing Binary Neutron Stars
Tidal interaction in a coalescing neutron star binary can resonantly excite the g-mode oscillations of the neutron star when the frequency of the tidal driving force equals the intrinsic g-mode frequencies. We study the g-mode oscillations of cold neutron stars using recent microscopic nuclear equations of state, where...
1994-04-25
2015-06-24
[ "astro-ph" ]
Dong Lai
astro-ph/9404063
Relativistic Dynamical Friction in the Weak Scattering Limit
A test mass, $M$, moving through an ambient medium of light particles with lower average kinetic energy than itself suffers a deceleration caused by its scattering of the light particles. The phenomenon is usually referred to as dynamical friction. The velocity, $\v$, of the test mass decays on a timescale independent ...
1994-04-25
2015-06-24
[ "astro-ph" ]
D. Syer
astro-ph/9404064
A Model for the Chemical Evolution of the Galaxy with Refuses
A model is presented for the chemical evolution of the solar neighbourhood which takes into account three families of galactic objects, according to their condensation states: stars, refuses and gas. Stars are defined as every condensed objects with masses greater than or equal to the minimum mass which ignites hydroge...
1994-04-25
2009-10-22
[ "astro-ph" ]
Helio J. Rocha-Pinto, Lilia I. Arany-Prado, Walter J. Maciel
astro-ph/9404059
Alignment and morphology of elliptical galaxies: the influence of the cluster tidal field
We investigate two possible effects of the tidal field induced by a spherical cluster on its elliptical galaxy members: the modification of the ellipticity of a spherical galaxy and the isophotal alignment in the cluster radial direction of a misaligned prolate galaxy. Numerical N-body simulations have been performed f...
1994-04-24
2015-06-24
[ "astro-ph" ]
L. Ciotti and S.N. Dutta
astro-ph/9404060
Frictional Heating and Neutron Star Thermal Evolution
Differential rotation between the neutron star crust and a more rapidly rotating interior superfluid leads to frictional heating that affects the star's long-term thermal evolution and resulting surface emission. Here we present the results of thermal evolution simulations based on two models of the vortex pinning forc...
1994-04-24
2009-10-22
[ "astro-ph" ]
K. Van Riper (LANL), B. Link (Montana), and R. Epstein (LANL)
astro-ph/9404061
Isocurvature Perturbations in Multiple Inflationary Models
Dynamics of long-wave isocurvature perturbations during an inflationary stage in multiple (multi-component) inflationary models is calculated analytically for the case where scalar fields producing this stage interact between themselves through gravity only. This enables to determine correct amplitudes of such perturba...
1994-04-24
2011-06-30
[ "astro-ph", "gr-qc" ]
D. Polarski and A. A. Starobinsky
astro-ph/9404055
Dynamics of Massive Shells Ejected in a Supernova Explosion
An expanding shell is accelerated outward by radiation from the remnant star and slowed by ram pressure and accretion as it plows into the interstellar medium. We set up the general relativistic equations of motion for such a shell. In the non-relativistic limit, the reduce to the standard Ostriker-Gunn equations. Furt...
1994-04-22
2007-05-23
[ "astro-ph" ]
D. Nunez and H. P. de Oliveira