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astro-ph/9503043
DIFFRACTION EFFECTS IN MICROLENSING OF Q2237+0305
Geometrical optics provides an excellent description for quasar images crossing caustics which are formed by gravitational microlensing of objects like Q2237+0305. Within this approximation the source size can be estimated from the maximum magnification reached at caustic crossings. We evaluate the limitations imposed ...
1995-03-10
2016-08-30
[ "astro-ph" ]
M. Jaroszynski (Warsaw Obs.) and B. Paczynski (Princeton Obs.)
astro-ph/9503044
The Structure of Supervoids -- I: Void Hierarchy in the Northern Local Supervoid
Supervoids are regions in the local Universe which do not contain rich clusters of galaxies. We have studied the closest example, the Northern Local Void, situated between the Local, Coma, and the Hercules superclusters. We find that this supervoid is not empty, but it contains small galaxy systems and poor clusters of...
1995-03-10
2016-08-30
[ "astro-ph" ]
Ulrich Lindner, Jaan Einasto, Maret Einasto, Wolfram Freudling, Klaus Fricke, Erik Tago
astro-ph/9503046
Figure Rotation and the Mass of the Galactic Bulge
The mass of the Galactic bulge, $M_B$, is estimated from the tensor virial theorem. By including the effects of a barred stellar distribution and figure rotation (81 \kms kpc $^{-1}$) and by assuming that the bar is oriented at $\theta$ $=$ 20\deg \ to our line of sight, $M_B$ is found to be as high as 2.8$\times$10$^{...
1995-03-10
2016-08-30
[ "astro-ph" ]
Robert Blum
astro-ph/9503045
Astrophysical Gamma Ray Emission Lines
We review the wide range of astrophysical observations of gamma ray emission lines and we discuss their implications. We consider line emission from solar flares, the Orion molecular cloud complex, supernovae 1987A and 1991T, the supernova remnants Cas A and Vela, the interstellar medium, the Galactic center region and...
1995-03-10
2016-08-30
[ "astro-ph" ]
R. Ramaty and R. E. Lingenfelter
astro-ph/9503042
A Parallel Processing Algorithm for Computing Short-Range Particle Forces with Inhomogeneous Particle Distributions
We present a computational algorithm for computing short range forces between particles. The algorithm has two distinguishing features. First, it is optimized for multi-processor computers, and will use as many processors as are available. Second, it is optimized for inhomogeneous, dynamic particle distributions; for a...
1995-03-10
2008-02-03
[ "astro-ph", "comp-gas", "nlin.CG" ]
Robert C. Ferrell and Edmund Bertschinger
astro-ph/9503047
Progress and Prospects in Neutrino Astrophysics
The neutrino deficits observed in four solar neutrino experiments, relative to the theoretical predictions, have led to fresh insights into neutrino and solar physics. Neutrino emission from distant, energetic astronomical systems may form the basis for a new field of astronomy. Additional experiments are needed to tes...
1995-03-10
2012-08-27
[ "astro-ph", "hep-ph", "nucl-ex" ]
John N. Bahcall, Kenneth Lande, Robert E. Lanou, Jr., John G. Learned, R. G. Hamish Robertson, and Lincoln Wolfenstein
astro-ph/9503041
A Nested Grid Particle-Mesh Code for High Resolution Simulations of Gravitational Instability in Cosmology
I describe a nested-grid particle-mesh (NGPM) code designed to study gravitational instability in three-dimensions. The code is based upon a standard PM code. Within the parent grid I am able to define smaller sub-grids allowing us to substantially extend the dynamical range in mass and length. I treat the fields on th...
1995-03-10
2015-06-24
[ "astro-ph" ]
R.J. Splinter (University of Kentucky)
astro-ph/9503040
The Accuracy of Mass Determination in Galaxy Clusters by X-ray Observations
We test the reliability of mass determination in clusters of galaxies by X-ray observations. The true mass in cluster models is compared to the mass derived by the X-ray emission and X-ray temperature of a model assuming hydrostatic equilibrium and spherical symmetry. In general we find good agreement between the X-ray...
1995-03-09
2016-08-30
[ "astro-ph" ]
Sabine Schindler (Max-Planck-Institut fuer extraterrestrische Physik)
astro-ph/9503038
The Effects of Substructure on Galaxy Cluster Mass Determinations
Although numerous studies of individual galaxy clusters have demonstrated the presence of significant substructure, previous studies of the distribution of masses of galaxy clusters determined from optical observations have failed to explicitly correct for substructure in those systems. In this {\it Letter} I present t...
1995-03-08
2016-08-30
[ "astro-ph" ]
Christina M. Bird
astro-ph/9503034
Imaging the Small-Scale Circumstellar Gas Around T~Tauri Stars
We have detected circumstellar molecular gas around a small sample of T Tauri stars through aperture synthesis imaging of CO(2-1) emission at ~2-3'' resolution. RY Tauri, DL Tauri, DO Tauri, and AS 209 show resolved and elongated gaseous emission. For RY Tau, the deconvolved, half-maximum radius along the direction of ...
1995-03-08
2016-08-30
[ "astro-ph" ]
D. W. Koerner and A. I. Sargent
astro-ph/9503037
Evolution of the Supercluster-Void Network
Recently, the observed cellular nature of the large-scale structure of the Universe with its quasi-regular pattern of superclusters and voids has been pointed out by several authors. In this paper, we investigate properties of the initial power spectrum which lead to prediction of structure consistent with these observ...
1995-03-08
2019-08-17
[ "astro-ph" ]
P. Frisch, J. Einasto, M. Einasto, W. Freudling, K.J. Fricke, M.Gramann, V. Saar, O. Toomet
astro-ph/9503039
Photon Statistics Limits for Earth-Based Parallax Measurements of MACHO Events
We analyze the limitations imposed by photon counting statistics on extracting useful information about MACHOs from Earth-based parallax observations of microlensing events. We find that if one or more large (say $2.5\,\rm m$) telescopes are dedicated to observing a MACHO event for several nights near maximum amplifica...
1995-03-08
2016-08-30
[ "astro-ph", "gr-qc" ]
Daniel E. Holz and Robert M. Wald
astro-ph/9503035
Gravitational Microlensing by Random Motion of Stars: Analysis of Light Curves
We present a quantitative analysis of the effect of microlensing caused by random motion of individual stars in the galaxy which is lensing a background quasar. We calculate a large number of magnification patterns for positions of the stars slightly offset from one frame to the next, and in this way obtain light curve...
1995-03-08
2016-08-30
[ "astro-ph" ]
Joachim Wambsganss and Tomislav Kundic
astro-ph/9503036
Possible Extragalactic Sources of the Highest Energy Cosmic Rays
We give an outline of possible extragalactic explanations of the highest energy cosmic ray events. We give a classification of the possible particles which could have caused the events and try to find suitable sources for each class. In contrast to some previous investigations of other authors, we find a possible candi...
1995-03-08
2011-04-15
[ "astro-ph" ]
Joerg P. Rachen (MPIfR Bonn)
astro-ph/9503033
Three-Point Correlations in the COBE-DMR Two-Year Anisotropy Maps
We compute the three-point temperature correlation function of the COBE Differential Microwave Radiometer (DMR) two-year sky maps to search for evidence of non-Gaussian temperature fluctuations. We detect three-point correlations in our sky with a substantially higher signal-to-noise ratio than from the first year data...
1995-03-07
2009-10-28
[ "astro-ph" ]
G. Hinshaw, A. J. Banday, C. L. Bennett, K. M. Gorski, and A. Kogut
astro-ph/9503030
Dynamical Modeling of NGC 7252 and the Return of Tidal Material
Motivated by recent neutral hydrogen observations with the VLA, we have undertaken an investigation into the interaction that produced the well known merger remnant NGC 7252. Through fully self-consistent N-body simulations, we are able to reproduce the kinematic character of the HI observations quite well, including t...
1995-03-07
2016-08-30
[ "astro-ph" ]
John Hibbard (U Hawaii) and Chris Mihos (UC Santa Cruz)
astro-ph/9503031
OY Car During Normal Outburst: Balmer Emission From The Red Star And The Gas Stream
We present observations of OY Car, obtained with the Anglo-Australian Telescope, during a normal outburst in August 1991. Two sinusoidal components are resolved in the H$\beta$ trailed spectra and we determine the location of the narrow component to be on the secondary star with a maximum contributed flux of ~2.5 per c...
1995-03-07
2016-08-30
[ "astro-ph" ]
E.T. Harlaftis, T.R. Marsh
astro-ph/9503032
The central bar in M94
Visual, NIR, and H_alpha surface photometry of the oval disk galaxy M94 (NGC 4736) was performed to study the distribution of mass in old stars and the distribution of the warm emission line gas. The radial profile of the inner stellar disk is steeper than exponential and displays twisted and deformed isophotes. Dust i...
1995-03-07
2016-08-30
[ "astro-ph" ]
C.Moellenhoff, M.Matthias and O.E. Gerhard
astro-ph/9503028
SPECTROPHOTOMETRIC INDICES AND METAL CONTENT OF GALACTIC GLOBULAR CLUSTERS
Spectrophotometric indices for $18$ Galactic globular clusters, obtained from CCD observations and careful reductions, were used to determine reliable calibrations on metallicity $[Fe/H]$. The indices were measured in the bandpasses adopted by Burnstein et al. (\cite{BFGK84}). Adding other observations of Burnstein et ...
1995-03-06
2016-08-30
[ "astro-ph" ]
S. Covino, S. Galletti and L.E. Pasinetti (Dip. di Fisica, Univ. di Milano)
astro-ph/9503029
Hard X-ray emission from extragalactic IRAS 12um sources: constraints on the unified AGN model and the synthesis of the X-ray background
We analyze the $2-10$~keV X-ray emission of complete samples of AGN and galaxies selected at 12$\mu$m and recently compiled by Rush, Malkan \& Spinoglio (1993). As a necessary complement we also study the IR emissivity of the largest sample of hard X--ray selected AGN (Grossan 1992). Our purposes are to probe the unifi...
1995-03-06
2016-08-30
[ "astro-ph" ]
X. Barcons, A. Franceschini, G. De Zotti, L. Danese, T. Miyaji
astro-ph/9503025
Self-Similar Evolution of Cosmological Density Fluctuations
The gravitational evolution of scale free initial spectra $P(k)\propto k^n$ in an Einstein-de Sitter universe is widely believed to be self-similar for $-3<n<4$. However, for $-3<n<-1$ the existence of self-similar scaling has not been adequately demonstrated. Here we investigate the possible breaking of self-similar s...
1995-03-06
2009-10-28
[ "astro-ph" ]
Bhuvnesh Jain and Edmund Bertschinger
astro-ph/9503026
THREE-DIMENSIONAL HYDRODYNAMIC BONDI-HOYLE ACCRETION. IV. SPECIFIC HEAT RATIO 4/3.
We investigate the hydrodynamics of three-dimensional classical Bondi-Hoyle accretion. A totally absorbing sphere of different sizes (1, 0.1 and 0.02 accretion radii) exerts gravity on and moves at different Mach numbers (0.6, 1.4, 3.0 and 10) relative to a homogeneous and slightly perturbed medium, which is taken to b...
1995-03-06
2011-05-23
[ "astro-ph" ]
M. Ruffert (Max-Planck-Institut fuer Astrophysik)
astro-ph/9503027
COALESCING NEUTRON STARS AS GAMMA RAY BURSTERS ?
We investigate the dynamics and evolution of coalescing neutron stars. The three-dimensional Newtonian equations of hydrodynamics are integrated by the `Piecewise Parabolic Method' However, we do include the effects of the emission of gravitational waves on the hydrodynamics. The properties of neutron star matter are d...
1995-03-06
2016-08-30
[ "astro-ph" ]
M. Ruffert, H.-Th. Janka, W. Keil, (Max-Planck-Institut fuer Astrophysik) and G. Schaefer (MPG-Arbeitsgruppe Gravitationstheorie)
astro-ph/9503024
Multi-Frequency Monitoring of the Seyfert 1 Galaxy NGC~4593 II: a Small, Compact Nucleus ?
We discuss the results of a campaign to monitor spectral variations in the low-luminosity Seyfert~1 galaxy NGC~4593, at X-rays, ultraviolet, optical and near IR frequencies. The observations and data analysis have been described in a companion paper (Santos-Lle\'o et al. 1994; Paper~1). The active nucleus in this galax...
1995-03-06
2015-06-24
[ "astro-ph" ]
M. Santos-Lleo, J. Clavel, P. Barr, I.S. Glass, D. Pelat, B.M. Peterson, G. Reichert
astro-ph/9503022
On the Dynamics of the Sagittarius Dwarf Galaxy
We use numerical simulations to test the feasibility of the suggestion by Ibata et al. (1994) that the excess population of stars which they discovered in the Sagittarius region may be the disrupted remains of a dwarf spheroidal galaxy. We find that a Fornax-like model for the pre-disruption system can indeed reproduce...
1995-03-05
2016-06-08
[ "astro-ph" ]
H. Velazquez and S.D.M. White
astro-ph/9503021
SEARCH FOR VERY LOW MASS OBJECTS IN THE GALACTIC HALO
We present results from a search for gravitational microlensing of stars in the Large Magellanic Cloud by low mass objects in the Galactic Halo. The search uses the CCD light curves of about 82,000 stars with up to 46 measurements per night over a period of 10 months. No light curve exhibits a form that is consistent w...
1995-03-05
2011-05-23
[ "astro-ph" ]
EROS collaboration: E. Aubourg, P. Bareyre, S. Brehin, M. Gros, M. Lachieze-Rey, B. Laurent, E. Lesquoy, C. Magneville, A. Milsztajn, L. Moscoso, F. Queinnec, J. Rich, M. Spiro, L. Vigroux, S. Zylberajch, R. Ansari, F. Cavalier, M. Moniez, J. P. Beaulieu, R. Ferlet, Ph. Grison, A. Vidal-Madjar, E. Maurice, L. P...
astro-ph/9503020
Status of Cosmological Parameters: Can $\Omega=1$?
I discuss the Hubble parameter $H_0$, the age of the universe $t_0$, the density $\Omega_0$, and the cosmological constant $\Lambda$. To focus the discussion, I concentrate on the issue of the value of the density $\Omega_0$ in currently popular cosmological models in which most of the dark matter is cold, especially C...
1995-03-04
2016-08-30
[ "astro-ph", "hep-ph" ]
Joel R. Primack
astro-ph/9503018
Cluster Abundance from Perturbation Spectra with Broken Scale Invariance
A double inflationary model with enhanced power at large scales --- Broken Scale Invariant perturbations (BSI) --- leads to a promising scenario for the formation of large-scale structure. We use high-resolution PM simulations with a model for the thermodynamic evolution of baryons. Galactic halos are identified as pea...
1995-03-03
2016-08-30
[ "astro-ph" ]
Volker Muller
astro-ph/9503015
The First Second of a Type-II Supernova: Convection, Accretion, and Shock Propagation
One- and two-dimensional hydrodynamical simulations of neutrino-driven supernova explosions are discussed. The simulations cover the phase between the stagnation of the prompt shock and about one second after core bounce. Systematic variation of the neutrino fluxes from the neutrino sphere shows that the explosion ener...
1995-03-03
2016-09-07
[ "astro-ph" ]
H.-Thomas Janka and Ewald Mueller (Univ of Chicago and Max-Planck-Institut fuer Astrophysik)
astro-ph/9503023
Gravitational redshift in the NGC 4258 disk?
The recent observations of high-velocity maser emissions in NGC 4258 by Myoshi et al provide strong evidence for a central object of mass 3.6 10**7 solar masses in the nucleus of this galaxy based on a kinematic argument. However, they should allow an independent determination of the central object mass via gravitation...
1995-03-03
2016-08-30
[ "astro-ph" ]
Alain Smette, Konrad Kuijken (Kapteyn Astronomical Institute, Groningen)
astro-ph/9503016
The Orion OB1 Association II. The Orion-Eridanus Bubble
Observations of the interstellar medium in the vicinity of the Orion OB1 association show a cavity filled with hot ionized gas, surrounded by an expanding shell of neutral hydrogen (the Orion-Eridanus Bubble). In this paper we examine this cavity and the surrounding bubble with the aid of data from the Leiden/Dwingeloo...
1995-03-03
2016-08-30
[ "astro-ph" ]
A.G.A. Brown, D. Hartmann, W.B. Burton (Sterrewacht Leiden, CfA)
astro-ph/9503019
THE NEED FOR A PARADIGM SHIFT IN OPTICAL ASTRONOMY: A SOLUTION GIVEN BY LIQUID MIRRORS AND EXAMPLES OF THEIR APPLICATIONS TO COSMOLOGY
I argue that there is a crisis in optical Astronomy due to a paucity of telescopes and thus the need for a paradigm shift in telescope technology. Large increases in collecting areas and observing time/astronomer are only possible if we forgo the fully steerable multipurpose telescope with a glass primary mirror that h...
1995-03-03
2007-05-23
[ "astro-ph" ]
E.F. Borra
astro-ph/9503017
The Hot Big Bang and Beyond
The hot big-bang cosmology provides a reliable accounting of the Universe from about $10^{-2}\sec$ after the bang until the present, as well as a robust framework for speculating back to times as early as $10^{-43}\sec$. Cosmology faces a number of important challenges; foremost among them are determining the quantity ...
1995-03-03
2014-10-13
[ "astro-ph", "hep-ph" ]
Michael S. Turner (Univ. Chicago/Fermilab)
astro-ph/9503010
COMPARISON OF N-BODY SIMULATIONS TO STATISTICAL OBSERVATIONS OF GALAXY PAIRS
N-body simulations were conducted of pairs of galaxies with a 3:1 mass ratio on parabolic orbits, in order to quantify the effect of dynamical friction. The effects of varying the ratio of the dark matter halo size to the distance of closest approach were explored. Once the dark matter halos are fully overlapping, the ...
1995-03-02
2016-08-30
[ "astro-ph" ]
Roger E. Bartlett and Jane C. Charlton
astro-ph/9503013
ROSAT observations of the galaxy group AWM7
We present results of ROSAT/PSPC and HRI observations of the AWM7 group of galaxies, which is a poor galaxy cluster and forms part of the Perseus-Pisces filament. The X-ray emission originates from intracluster gas at temperatures of 1.7 to 4.5 keV. The cluster obviously is elliptical with a position angle perpendicula...
1995-03-02
2016-08-30
[ "astro-ph" ]
Doris M. Neumann & Hans Boehringer
astro-ph/9503011
Weak Lensing by Large Scale Structure in Open, Flat, and Closed Universes
Weak lensing is the distortion (polarization) of images of distant objects, such as high redshift galaxies, by gravitational fields in the limit where the distortion is small. Gravitational potential fluctuations due to large scale structure cause correlated distortions of the images of high redshift galaxies. These di...
1995-03-02
2015-06-24
[ "astro-ph" ]
Jens Verner Villumsen (Max Planck Institut fuer Astrophysik, Garching bei Muenchen, Germany)
astro-ph/9503014
TOPOLOGICAL DEFECTS AND HIGHEST ENERGY COSMIC AND GAMMA RAYS
In this paper we review the hypothesis that a considerable part of the cosmic ray flux observed above about $10^{19}\eV$ may be produced by decaying or annihilating topological defects left over from phase transitions in the early universe at grand unification energy scales ($\approx10^{16}\GeV$). Possible signatures o...
1995-03-02
2010-11-01
[ "astro-ph" ]
G.Sigl
astro-ph/9503012
ROSAT HRI Observations of the Crab Pulsar: An Improved Temperature upper limit for PSR 0531+21
ROSAT HRI observations have been used to determine an upper limit of the Crab pulsar surface temperature from the off-pulse count rate. For a neutron star mass of 1.4 \Mo and a radius of 10 km as well as the standard distance and interstellar column density, the redshifted temperature upper limit is\/ $T_s^\infty \le 1...
1995-03-02
2016-08-30
[ "astro-ph" ]
W. Becker and B. Aschenbach (Max-Planck-Institut f\"ur extraterrestrische Physik, Garching, Germany)
astro-ph/9503006
TYPE Ib/c SUPERNOVAE AND THEIR RELATION TO BINARY STARS
The present understanding of type Ib/c supernovae and their connection to interacting binaries is reviewed. The problems of the classification and the lack of well-observed events exclude direct inference of progenitor characteristics. The absence of hydrogen lines in the observed spectrum, nevertheless, requires restr...
1995-03-01
2016-08-30
[ "astro-ph" ]
Bruno Leibundgut
astro-ph/9503005
New results on the Gunn-Peterson Effect at High Redshift
Attempts to measure the optical depth due to a diffuse intergalactic medium (IGM) in the spectra of high redshift quasars (GP test) within the ESO key program on the intergalactic medium are reviewed. It is shown that there is no evidence for any Gunn-Peterson effect up to the highest redshifts observable in quasar spe...
1995-03-01
2016-08-30
[ "astro-ph" ]
E. Giallongo, S. D'Odorico, A. Fontana, S. Savaglio, S. Cristiani, P. Molaro
astro-ph/9503007
COSMOLOGICAL EVOLUTION OF EXTRAGALACTIC SOURCES IN THE INFRARED AND CONTRIBUTIONS TO THE BACKGROUND RADIATION
Infrared surveys provide essential insights on galaxy evolution. If near-IR studies suggest mild evolution of stellar populations with cosmic time, indications of a substantial evolution have been seen in the far-IR, although the available information is largely insufficient to delineate precise evolutionary properties...
1995-03-01
2016-08-30
[ "astro-ph" ]
G. DeZotti, A. Franceschini, P. Mazzei, L. Granato, L. Danese
astro-ph/9503004
The Primordial Perturbation Spectrum and Large Scale Structure
Observational constraints on standard CDM spectra and perturbation spectra with broken scale invariance are discussed.
1995-03-01
2016-08-30
[ "astro-ph" ]
Stefan Gottloeber (Astrophysical Institute Potsdam)
astro-ph/9503008
An observational test of common-envelope evolution
By analysing and modelling the change in the abundance ratio of $^{12}$C/$^{13}$C and $^{16}$O/$^{17}$O on the surface of the lower mass star of a binary during the common-envelope (CE) phase of evolution, we propose a simple observational test of the CE scenario. The test is based on the infrared measurement of either...
1995-03-01
2016-06-08
[ "astro-ph" ]
M. J. Sarna, V. S. Dhillon, T. R. Marsh, and P. B. Marks
astro-ph/9503009
Absolute-Magnitude Calibration for W~UMa-type Systems. II. Influence of Metallicity
A modification to the absolute magnitude calibration for W~UMa-type systems, taking into account differences in metal abundances, is derived on the basis of contact binary systems recently discovered in metal-poor clusters. A preliminary estimate of the magnitude of the metallicity-dependent term for the $(B-V)$-based ...
1995-03-01
2016-08-30
[ "astro-ph" ]
Slavek Rucinski
astro-ph/9503002
The Two--Point Correlation Function and the Size of Voids
Under the assumption of a void-filled Universe we investigate if the characteristic scale of voids can be determined from existing surveys. We use the Voronoi tessellation to create mock surveys and study the properties of the first zero-crossing of the two-point correlation function for various survey geometries. Our ...
1995-03-01
2015-06-24
[ "astro-ph" ]
Dalia S. Goldwirth, Luiz Nicolaci da Costa and Rien Van de Weygaert
astro-ph/9503001
AUTOMATED MORPHOLOGICAL CLASSIFICATION OF APM GALAXIES BY SUPERVISED ARTIFICIAL NEURAL NETWORKS
We train Artificial Neural Networks to classify galaxies based solely on the morphology of the galaxy images as they appear on blue survey plates. The images are reduced and morphological features such as bulge size and the number of arms are extracted, all in a fully automated manner. The galaxy sample was first class...
1995-03-01
2015-06-24
[ "astro-ph" ]
A. Naim, O. Lahav, L. Sodre Jr. and M. C. Storrie-Lombardi
astro-ph/9503003
WRAY 977 (GX301-2): A HYPERGIANT WITH PULSAR COMPANION
Wray 977, the B supergiant companion of the X-ray pulsar GX301-2, should be classified as B1~Ia+, based on a comparison of its optical spectrum to that of zeta1 Sco, a well-known B hypergiant and ONE OF THE BRIGHTEST STARS IN THE GALAXY. The classification of Wray 977 as a hypergiant results in a new distance determina...
1995-03-01
2016-08-30
[ "astro-ph" ]
L. Kaper, H.J.G.L.M. Lamers, E. Ruymaekers, E.P.J. van den Heuvel and E.J. Zuiderwijk
astro-ph/9502105
THE ORBITAL ECCENTRICITIES OF BINARY MILLISECOND PULSARS IN GLOBULAR CLUSTERS
Low-mass binary millisecond pulsars (LMBPs) are born with very small orbital eccentricities, typically of order $e_i\sim10^{-6}$--$10^{-3}$. In globular clusters, however, higher eccentricities $e_f\gg e_i$ can be induced by dynamical interactions with passing stars. Here we show that the cross section for this process...
1995-02-28
2016-08-30
[ "astro-ph" ]
Frederic A. Rasio and Douglas C. Heggie
astro-ph/9502104
Distribution of proper motions in spherical star clusters
Along with data on radial velocities, more and more data on proper motions of individual stars in globular clusters are becoming available. Their usage was until now rather limited. It was mostly restricted to determining cluster membership of individual stars and to determining the spatial velocity of the cluster. We ...
1995-02-28
2016-08-30
[ "astro-ph" ]
M. Wybo and H. Dejonghe
astro-ph/9502106
ON BLUE STRAGGLER FORMATION BY DIRECT COLLISIONS OF MAIN-SEQUENCE STARS
We report the results of new SPH calculations of parabolic collisions between main-sequence (MS) stars. The stars are assumed to be close to the MS turn-off point in a globular cluster and are therefore modeled as $n=3$, $\Gamma=5/3$ polytropes. We find that the high degree of central mass concentration in these stars ...
1995-02-28
2012-08-27
[ "astro-ph" ]
James C. Lombardi, Jr., Frederic A. Rasio, and Stuart L. Shapiro
astro-ph/9502103
TEMPERATURE DISTRIBUTION FUNCTION OF X-RAY CLUSTERS OF GALAXIES IN A NEUTRINO DOMINATED UNIVERSE
The temperature distribution function (TDF) of X-ray clusters is derived for different normalizations of the HDM power spectrum in an Omega_0=1 universe using the statistics of peaks of a random Gaussian field. Concerning cluster formation only, the neutrino picture appears to be marginally consistent with observations...
1995-02-28
2010-11-30
[ "astro-ph" ]
C. Balland and A. Blanchard
astro-ph/9502101
The IRAS 1.2 Jy Survey: Redshift Data
We present the redshift data for a survey of galaxies selected from the data base of the Infrared Astronomical Satellite (IRAS). This survey extends the 1.936 Jy sample of Strauss et al. (1992) from a flux limit of 1.936 Jy at 60 microns to 1.2 Jy. The survey extension consists of 3920 sources in the flux interval 1.2 ...
1995-02-27
2016-08-30
[ "astro-ph" ]
Karl Fisher, John Huchra, Michael Strauss, Marc Davis, Amos Yahil, and David Schlegel
astro-ph/9502100
THE LYMAN-ALPHA FOREST AT LOW REDSHIFT: TRACING THE DARK MATTER FILAMENTS
We study the distribution of low-redshift Ly$\alpha$ clouds in a CDM model using numerical simulations including photoionization and cooling of the baryonic component. The ionizing background is found to be efficient enough to keep most of the gas warm ($T$~=~1--5~10$^4$~K) and to prevent most of it from collapsing. In...
1995-02-27
2016-08-30
[ "astro-ph" ]
Patrick Petitjean, Jan P. M\"ucket and Ron Kates
astro-ph/9502102
AGAPE, an experiment to detect MACHO's in the direction of the Andromeda galaxy
The status of the Agape experiment to detect Machos in the direction of the andromeda galaxy is presented.
1995-02-27
2016-08-30
[ "astro-ph" ]
R. Ansari, M. Auri\'ere, P. Baillon, A. Bouquet, G. Coupinot, C. Coutures, C. Ghesqui\`ere, Y. Giraud-H\'eraud, P. Gondolo, J. Hecquet, J. Kaplan, A.L. Melchior, M. Moniez, J.P. Picat and G. Soucail
astro-ph/9502099
X-ray Spectrum of the Black Hole Candidate X1755-338
We report the first detection of a hard power-law tail in the X-ray spectrum of the black hole candidate (BHC) binary X1755-338, which was observed in 1989 March-September during the TTM Galactic Centre survey. In addition, an ultrasoft thermal component with a temperature of ~1.1-1.4 keV was also detected. We demonstr...
1995-02-27
2016-06-08
[ "astro-ph" ]
H.C. Pan, G.K. Skinner, R.A. Sunyaev, and K.N. Borozdin
astro-ph/9502095
Constraints on CDM theories from observations of massive, X-ray luminous clusters of galaxies at high redshift
During the course of a gravitational lensing survey of distant, X-ray selected, EMSS clusters of galaxies, we have studied 6 X-ray luminous (Lx > 5x10^44 h_{50}^{-2} erg s^{-1}) clusters at redshifts exceeding z=0.5. All of these clusters are apparently massive. In addition to their high X-ray luminosity, two of the cl...
1995-02-26
2016-08-30
[ "astro-ph" ]
G. A. Luppino and I. M. Gioia (Institute for Astronomy, University of Hawaii)
astro-ph/9502096
The Ages of Elliptical Galaxies in a Merger Model
The tightness of the observed colour-magnitude and Mg$_{2}$- velocity dispersion relations for elliptical galaxies has often been cited as an argument against a picture in which ellipticals form by the merging of spiral disks. A common view is that merging would mix together stars of disparate ages and produce a large ...
1995-02-26
2015-06-24
[ "astro-ph" ]
Guinevere Kauffmann
astro-ph/9502098
Accretion Disks
This is an introduction to accretion disk theory, with emphasis on aspects relevant for X-ray Binaries and Cataclysmic Variables. The text corrects some mistakes in an earlier version, which appeared in 'Lives of Neutron Stars', A. Alpar, \"U. Kizilo\u glu and J. van Paradijs (eds.), Kluwer, Dordrecht (NATO ASI series,...
1995-02-26
2016-08-30
[ "astro-ph" ]
H.C. Spruit (Max Planck Institute for Astrophysics, P.O. Box 1523, D-85740 Garching, Germany)
astro-ph/9502097
TWO-POINT ANGULAR CORRELATION FUNCTION FOR THE GREEN BANK 4.85 GHZ SKY SURVEY
This paper presents an angular correlation analysis of the Green Bank 4.85 GHz radio catalog (Gregory \& Condon 1991) of 54,579 sources (S \gsim 25 mJy). The Green Bank catalog is found to be complete to S $\geq$ 35 mJy over 20$^{\circ} \leq \delta < 74^{\circ}$, 0$^h \leq \alpha < 24^h$, and Galactic latitude $|b| \ge...
1995-02-26
2016-08-30
[ "astro-ph" ]
Brian L. Kooiman, Jack O. Burns, and Anatoly A. Klypin
astro-ph/9502094
AN IMAGING K-BAND SURVEY - II: THE REDSHIFT SURVEY AND GALAXY EVOLUTION IN THE INFRARED
We present a redshift survey of 124 galaxies, from an imaging $K$-band survey complete to $K\simeq 17.3$. The optical-to-infrared colours are consistent with the range expected from synthetic galaxy spectra, although there are some cases of very red nuclei. Our data show no evidence for evolution of the $K$-band lumino...
1995-02-24
2015-06-24
[ "astro-ph" ]
Karl Glazebrook, J. A. Peacock, L. Miller, C. A. Collins
astro-ph/9502093
A method for solving the linearized Boltzmann equation for almost uniformly rotating stellar disks.
We construct analytical phase-space solutions for perturbations of flat disks by performing a power series expansion for the radius and the velocity coordinates. We show that this approach translates into an elegant mathematical formulation which is easy to use for a wide variety of distribution functions, for as far a...
1995-02-23
2011-05-23
[ "astro-ph" ]
P. Vauterin and H. Dejonghe
astro-ph/9502092
Einstein Observatory evidence for the widespread baryon overdensity in clusters of galaxies,
We analyse the X-ray surface brightness profiles of 19 moderately distant and luminous clusters of galaxies observed with the \EINOBS. Our aim is to determine cluster gas masses out to radii between 1 and $3\Mpc$, and to confirm the apparent conflict, if $\Omega_0=1$, between the current calculations of the mean baryon...
1995-02-22
2015-06-24
[ "astro-ph" ]
D.A. White and A.C. Fabian,
astro-ph/9502091
ROTATION CURVES OF 967 SPIRAL GALAXIES
We present the rotation curves (RCs) of 967 spiral galaxies, obtained by folding and deprojecting the raw optical data by Mathewson et al. (1992). Out of these, we have identified 80 excellent RCs and 820 fair RCs. The 80 excellent RCs are smooth, symmetric, have negligible rms internal error, extend to at least the op...
1995-02-22
2016-08-30
[ "astro-ph" ]
Massimo Persic and Paolo Salucci
astro-ph/9502089
The angular correlation hierarchy in the quasilinear regime.
For Gaussian initial conditions the perturbation theory predicts a very specific hierarchy for the projected matter $p$-point correlation functions. In the small angle approximation and assuming a power-law spectrum I derive the exact expressions of the coefficients $s_p$ relating the averaged $p$-order angular correla...
1995-02-21
2011-05-23
[ "astro-ph" ]
F. Bernardeau
astro-ph/9502090
Gamma-ray Burst Models: General Requirements and Predictions
Whatever the ultimate energy source of gamma-ray bursts turns out to be, the resulting sequence of physical events is likely to lead to a fairly generic, almost unavoidable scenario: a relativistic fireball that dissipates its energy after it has become optically thin. This is expected both for cosmological and halo di...
1995-02-21
2016-08-30
[ "astro-ph" ]
P. Meszaros
astro-ph/9502088
On the Morphology of Density Perturbations
The morphological distribution of primordial density peaks is assessed. Previous determinations, those of Peacock & Heavens (1985) and those of Bardeen et al (1986) have contradictory concluded that there exist a tendency towards prolate or towards oblate shapes, respectively. By using two methods, the Hessian and the ...
1995-02-21
2007-05-23
[ "astro-ph" ]
Alejandro Gonzalez S. and Oscar Martinez (Instituto Nacional de Astrofisica, Optica y Elect)
astro-ph/9502087
Constraints on Self-Interacting Dark Matter
We consider the growth of density perturbations in the presence of self--interacting dark matter, SIDM, proposed by Carlson, Machacek and Hall (1992). We determine the range of values for the coupling constant $\lambda$ and the particle mass $m^\prime$, for which the power spectrum lies in the ``allowed" range based on...
1995-02-20
2011-05-12
[ "astro-ph" ]
Andrew A. de Laix, Robert J. Scherrer and Robert K. Schaefer
astro-ph/9502085
TEV GAMMA-RAYS FROM PROTON BLAZARS
Proton acceleration in nearby blazars can be diagnosed measuring their intense TeV $\gamma$-ray emission. Flux predictions for 1101+384 (Mrk421) and 1219+285 (ON231), both strong EGRET sources (0.1-10 GeV), are obtained from model spectra of unsaturated synchrotron pair cascades fitted to publicly available multifreque...
1995-02-20
2009-10-28
[ "astro-ph" ]
Karl Mannheim
astro-ph/9502086
W~UMa-type Systems in the Central Baade Window Discovered in the OGLE Experiment
77 W~UMa-type systems to $I=18$ mag in one of the 21 fields of OGLE have been assessed in terms of utility for extraction of astrophysical information from time-independent data such as colors, periods, maximum magnitudes, and variability amplitudes in the final global OGLE catalog which will contain $>1000$ contact bi...
1995-02-20
2016-08-30
[ "astro-ph" ]
Slavek M. Rucinski (David Dunlap Observatory, Toronto)
astro-ph/9502084
HST Images of the Eclipsing Pulsar B1957+20
We have obtained images of the eclipsing pulsar binary PSR~B1957+20 using the Planetary Camera of the Hubble Space Telescope. The high spatial resolution of this instrument has allowed us to separate the pulsar system from a nearby background star which has confounded ground-based observations of this system near optic...
1995-02-19
2016-08-30
[ "astro-ph" ]
Andrew S. Fruchter, Jay Bookbinder and Charles D. Bailyn
astro-ph/9502083
MODELS OF LYMAN-ALPHA CLOUDS
The classic question regarding Lyman-alpha forest clouds is whether they are confined by the pressure of a hot, diffuse surrounding medium, or by the gravity of dark matter mini-halos. This paper reviews these basic models for forest clouds, considering spherical and slab geometries. At high redshift, the clouds are st...
1995-02-19
2016-08-30
[ "astro-ph" ]
Jane C. Charlton
astro-ph/9502082
Radio Survey of W UMa-type Systems
12 W~UMa-type systems were observed at 3.6 cm with a goal to compare their radio luminosities with those of non-contact, rapidly rotating, late-type stars. Only 3 systems, all of spectral type K, have been detected. The detections and (low) upper limits for remaining systems confirm the strong under-luminosity of W~UMa...
1995-02-17
2016-08-30
[ "astro-ph" ]
Slavek Rucinski, David Dunlap Observatory
astro-ph/9502081
Do experiments and astrophysical considerations suggest an inverted neutrino mass hierarchy?
The recent results from the Los Alamos neutrino oscillation experiment, together with assumptions of neutrino oscillation solutions for the solar and atmospheric neutrino deficit problems, may place powerful constraints on any putative scheme for neutrino masses and mixings. Assuming the validity of these experiments a...
1995-02-17
2016-08-30
[ "astro-ph", "hep-ph" ]
George M. Fuller (University of California, San Diego), Joel R. Primack (University of California, Santa Cruz), and Yong-Zhong Qian (Institute for Nuclear Theory, University of Washington)
astro-ph/9502080
Matter-enhanced antineutrino flavor transformation and supernova nucleosynthesis
Matter-enhanced antineutrino flavor transformation between $\bar\nu_e$ and $\bar\nu_{\mu(\tau)}$ can occur in supernovae if the vacuum masses for these species satisfy $m_{\bar\nu_e}>m_{\bar\nu_{\mu(\tau)}}$. For $\delta m^2> 1$ eV$^2$, such flavor transformation can affect the electron fraction $Y_e$ in the neutrino-h...
1995-02-17
2016-08-30
[ "astro-ph", "hep-ph" ]
Yong-Zhong Qian (Institute for Nuclear Theory, University of Washington) and George M. Fuller (University of California, San Diego)
astro-ph/9502076
Lyman alpha Emission from High-Redshift Galaxies
We summarise the results of a deep search for Lyman alpha emission from star-forming regions associated with damped Lyman alpha absorption systems and conclude that the Lyman alpha luminosity of high redshift galaxies is generally less than 10^(42) erg/s . We also present a newly discovered case, in the field of the QS...
1995-02-16
2016-08-30
[ "astro-ph" ]
Max Pettini (RGO), Richard W. Hunstead (Sydney University) David L. King (RGO), and Linda J. Smith (University College London)
astro-ph/9502077
Element Abundances at High Redshifts: The N/O Ratio in a Primeval Galaxy
The damped Lyman alpha systems seen in the spectra of high redshift QSOs offer the means to determine element abundances in galaxies observed while still at an early stage of evolution. Such measurements, which have only recently come within reach, complement and extend the data provided by studies of different stellar...
1995-02-16
2016-08-30
[ "astro-ph" ]
Max Pettini (RGO), Keith Lipman (IoA), and Richard W. Hunstead (Sydney University)
astro-ph/9502079
The density and peculiar velocity fields of nearby galaxies
We review the quantitative science that can be and has been done with redshift and peculiar velocity surveys of galaxies in the nearby universe. After a brief background setting the cosmological context for this work, the first part of this review focuses on redshift surveys. The practical issues of how redshift survey...
1995-02-16
2016-08-30
[ "astro-ph" ]
Michael A. Strauss and Jeffrey A. Willick
astro-ph/9502078
A COMPARATIVE STUDY OF MORPHOLOGICAL CLASSIFICATIONS OF APM GALAXIES
We investigate the consistency of visual morphological classifications of galaxies by comparing classifications for 831 galaxies from six independent observers. The galaxies were classified on laser print copy images or on computer screen produced from scans with the Automated Plate Measuring (APM) machine. Classificat...
1995-02-16
2015-06-24
[ "astro-ph" ]
A. Naim, O. Lahav, R. J. Buta, H. G. Corwin Jr., G. de Vaucouleurs, A. Dressler, J. P. Huchra, S. van den Bergh, S. Raychaudhury, L. Sodre Jr. and M. C. Storrie-Lombardi
astro-ph/9502073
A new criterion for Bar-Forming Instability in Rapidly Rotating Gaseous and Stellar Systems. I. Axisymmetric Form
This paper has been removed by arXiv admin because it was an erroneous duplicate of astro-ph/9411031.
1995-02-15
2009-10-28
[ "astro-ph" ]
D.M. Christodoulou, I. Shlosman and J.E. Tohline
astro-ph/9502072
INTERMEDIATE RESOLUTION SPECTROSCOPY OF THE RADIO GALAXY B2 0902+34 AT $Z\approx 3.4$
We have carried out spectroscopic observations of the high redshift ($z\approx 3.4$) radio galaxy 0902+34 at intermediate resolution with the William Herschel Telescope. The dynamical spectral ranges covered are 4600-5480 \AA and 5920-7680 \AA with resolutions of 5.4 \AA and 9.5 \AA, respectively. We detect a continuum...
1995-02-15
2016-08-30
[ "astro-ph" ]
J. M. Martin-Mirones, E. Martinez-Gonzalez, J. I. Gonzalez-Serrano, and J. L. Sanz
astro-ph/9502074
A new criterion for Bar-Forming Instability in Rapidly Rotating Gaseous and Stellar Systems. II. Nonaxisymmetric Form
We have previously introduced the parameter `alpha' as an indicator of stability to m=2 nonaxisymmetric modes in rotating, self-gravitating, axisymmetric, gaseous and stellar systems. This parameter can be written as a function of the total rotational kinetic energy, the total gravitational potential energy, and as a f...
1995-02-15
2016-08-30
[ "astro-ph" ]
D.M. Christodoulou, I. Shlosman and J.E. Tohline
astro-ph/9502075
A HEURISTIC REMARK ON THE PERIODIC VARIATION IN THE NUMBER OF SOLAR NEUTRINOS DETECTED ON EARTH
Four operating neutrino observatories confirm the long standing discrepancy between detected and predicted solar neutrino flux. Among these four experiments the Homestake experiment is taking data for almost 25 years. The reliability of the radiochemical method for detecting solar neutrinos has been tested recently by ...
1995-02-15
2016-08-30
[ "astro-ph" ]
H.J. Haubold and A.M. Mathai
astro-ph/9502069
The pattern speed of the bar in NGC 936
We have used the Tremaine-Weinberg method to measure the angular speed of rotation for the bar in the SB0 galaxy NGC 936. With this technique, the bar's pattern speed, Omega_p, can be derived from the luminosity and stellar-kinematic information in long-slit spectral observations taken parallel to the major axis of the...
1995-02-14
2015-06-24
[ "astro-ph" ]
Michael R. Merrifield and Konrad Kuijken
astro-ph/9502071
GB1508+5714: a radio-loud quasar with z=4.30 and the space density of high redshift, radio--loud quasars.
We report the discovery of a radio loud quasar with a redshift of 4.30. This object, which is the first radio selected quasar with a redshift greater than four, was discovered during an observational investigation into the evolution of the luminosity function of radio loud quasars. Here we describe results based on a s...
1995-02-14
2016-06-08
[ "astro-ph" ]
I. M. Hook, R. G. McMahon, A. R. Patnaik, I. W. A. Browne, P. N. Wilkinson, M. J. Irwin, C. Hazard
astro-ph/9502068
Spectral classification and HR diagram for symbiotic stars in the galactic bulge
A sample of 45 symbiotic stars observed in the direction of the galactic bulge are classified in spectral type using TiO $\lambda \lambda 6180, 7100 \AA$ and VO $\lambda \lambda 7865 \AA$ absorption feature indices and visual comparison. The effective temperatures obtained are used together with K data from the literat...
1995-02-14
2009-10-28
[ "astro-ph" ]
G. A. Medina Tanco and J. E. Steiner
astro-ph/9502070
INFRARED EMISSION AND DYNAMICS OF OUTFLOWS IN LATE-TYPE STARS
The dynamical structure and infrared emission of winds around late-type stars are studied in a self-consistent model that couples the equations of motion and radiative transfer. Both the dynamics and IR spectrum of the solution are fully characterized by the flux averaged optical depth. Five types of dust grains are co...
1995-02-14
2016-08-30
[ "astro-ph" ]
Zeljko Ivezic, Moshe Elitzur
astro-ph/9502065
An Eccentric Disk Model for the Nucleus of M31
The nucleus of M31 may be a thick eccentric disk, composed of stars traveling on nearly Keplerian orbits around a black hole or other dark compact object. This hypothesis reproduces most of the features seen in HST photometry of the center of M31; in particular the bright off-center source P1 is the apoapsis of the dis...
1995-02-13
2016-08-30
[ "astro-ph" ]
Scott Tremaine
astro-ph/9502066
Genus and spot density in the COBE DMR first year anisotropy maps
A statistical analysis of texture on the {\it COBE}-DMR first year sky maps based on the genus and spot number is presented. A generalized $\chi^2$ statistic is defined in terms of ``observable'' quantities: the genus and spot density that would be measured by different cosmic observers. This strategy together with the...
1995-02-13
2015-06-24
[ "astro-ph" ]
S. Torres, L. Cayon, E. Martinez-Gonzalez and J.L. Sanz
astro-ph/9502067
Generic Evolution Of Deuterium And Helium-3
The primordial abundances of deuterium and of helium-3, produced during big bang nucleosynthesis, depend sensitively on the baryon density. Thus, the observed abundances of D and \he may provide useful ``baryometers'' provided the evolution from primordial to present (or, presolar nebula) abundances is understood. Inev...
1995-02-13
2016-08-30
[ "astro-ph" ]
Gary Steigman and Monica Tosi
astro-ph/9502064
EVAPORATION OF QUARK DROPS DURING THE COSMOLOGICAL Q-H TRANSITION
We have carried out a study of the hydrodynamics of disconnected quark regions during the final stages of the cosmological quark-hadron transition. A set of relativistic Lagrangian equations is presented for following the evaporation of a single quark drop and results from the numerical solution of this are discussed. ...
1995-02-13
2016-08-30
[ "astro-ph", "hep-ph" ]
L. Rezzolla, J.C. Miller and O. Pantano
astro-ph/9502063
THE GUNN-PETERSON EFFECT FROM UNDERDENSE REGIONS IN A PHOTOIONIZED INTERGALACTIC MEDIUM
We use the Zel'dovich approximation and another analytical approximation to calculate the evolution under gravitational instability of the underdense regions of a photoionized intergalactic medium (IGM). We find that over most of the spectrum of a quasar, the optical depth to $\lya$ scattering originates from gas in un...
1995-02-13
2016-08-30
[ "astro-ph" ]
Andreas Reisenegger and Jordi Miralda-Escude
astro-ph/9502062
COLD + HOT AND COLD DARK MATTER COSMOLOGIES: ANALYSIS OF NUMERICAL SIMULATIONS
We present a series of four simulations of Cold Dark Matter (CDM) and Cold + Hot Dark Matter (CHDM) cosmologies. We discuss the power spectrum and correlation functions in real and redshift space, with comparisons to the CfA2 and IRAS redshift data, the pairwise velocity of galaxies, and the distribution of hot and col...
1995-02-12
2016-08-30
[ "astro-ph" ]
A.Klypin (NMSU), R.Nolthenius, and J.Primack (UCSC)
astro-ph/9502060
The Signatures of Voids and the CMBR
We explore the signature of a cold dark matter compensated void in the quasi non-linear regime. We find that this void is entirely a cold spot on the microwave background, in contrast to a non-linear void. On the last scattering surface(LSS), it appears as either a hot or cold spot depending on where this surface cuts ...
1995-02-11
2016-08-30
[ "astro-ph" ]
Sharon L. Vadas
astro-ph/9502059
The Double Cluster G185 in M31
We have identified a small globular cluster in M31 located approximately 4 arcseconds northwest of the M31 globular cluster G185. While several multiple globular clusters have been observed in the Magellanic Clouds none have been found in the Galaxy or in M31. We estimate the probability of such a chance line-of-sight ...
1995-02-11
2009-10-28
[ "astro-ph" ]
Stephen Holland, Gregory G. Fahlman, & Harvey B. Richer
astro-ph/9502061
Magnetically modulated accretion in T Tauri stars
We examine how accretion on to T Tauri stars may be modulated by a time-dependent `magnetic gate' where the inner edge of the accretion disc is disrupted by a varying stellar field. We show that magnetic field variations on time-scales shorter than 10^5 yr can modulate the accretion flow, thus providing a possible mech...
1995-02-11
2015-06-24
[ "astro-ph" ]
C.J. Clarke, P.J. Armitage, K.W. Smith and J.E. Pringle
astro-ph/9502054
Hubble Parameter in Void Universe
We investigate the distance-redshift relation in the simple void model. As discussed by Moffat and Tatarski, if the observer stays at the center of the void, the observed Hubble parameter is not so different from the background Hubble parameter. However, if the position of observer is off center of the void, we must co...
1995-02-10
2016-08-30
[ "astro-ph" ]
Ken-ichi Nakao, Naoteru Gouda, Takeshi Chiba, Satoru Ikeuchi, Takashi Nakamura and Masaru Shibata
astro-ph/9502056
The Large-Scale Distribution of Quasars
We report the investigation of spatial distribution of quasars using two different methods: the statistical study by means of 2-point correlation function and direct search for structures such as previously reported Large Quasar Groups. Having analyzed the combined sample of eight homogeneous quasar surveys (totalling ...
1995-02-10
2016-08-30
[ "astro-ph" ]
B.V.Komberg, A.V.Kravtsov, V.N.Lukash (Astro Space Center, Lebedev Physical Institute, Moscow)
astro-ph/9502057
LYMAN $\alpha$ FORESTS AND COOLING OUTFLOW FROM DWARF GALAXIES
We propose that cooling outflows from star-forming dwarf galaxies that are spatially correlated with but unbound to bright galaxies may account for the low column QSO Ly$\alpha$ forests, providing an explanation for both the heavy elements recently detected in them and the large sizes associated with them. Thus, we sug...
1995-02-10
2016-08-30
[ "astro-ph" ]
Boqi Wang (The Johns Hopkins University)
astro-ph/9502058
Binary Pulsar Shock Emissions as Galactic Gamma-Ray Sources
We address several issues regarding the interpretation of galactic \ggg-ray sources. We consider powerful pulsars in binaries producing X-ray and gamma-ray {\it unpulsed} emission from the shock interaction of relativistic pulsar winds with circumbinary material. Nebular mass outflows from companion stars of binary pul...
1995-02-10
2016-08-30
[ "astro-ph" ]
M. Tavani
astro-ph/9502055
HOT ACCRETION DISKS WITH ADVECTION
The global structure of optically thin hot accretion disks with radial advection included has been investigated. We solve the full energy conservation equation explicitly and construct the radial structure of the disk. It is found that advection is a real cooling process and that there are two solutions co-exist for a ...
1995-02-10
2016-08-30
[ "astro-ph" ]
Xingming Chen