id
large_stringlengths
9
16
title
large_stringlengths
1
382
abstract
large_stringlengths
3
6.09k
publish_date
date32
update_date
date32
categories
large listlengths
1
13
authors
large_stringlengths
3
62.8k
astro-ph/9507027
Neutrino pair synchrotron radiation from relativistic electrons in strong magnetic fields
The emissivity for the neutrino pair synchrotron radiation in strong magnetic fields has been calculated both analytically and numerically for high densities and moderate temperatures, as can be found in neutron stars. Under these conditions, the electrons are relativistic and degenerate. We give here our results in te...
1995-07-07
2009-10-28
[ "astro-ph" ]
A. Vidaurre, A. Perez, H. Sivak, J. Bernabeu and J.M. Ibanez
astro-ph/9507025
A Stellar Audit: The Computation of Encounter Rates for 47 Tucanae and omega Centauri
Using King-Mitchie Models, we compute encounter rates between the various stellar species in the globular clusters $\omega$ Cen, and 47 Tuc. We also compute event rates for encounters between single stars and a population of primordial binaries. Using these rates, and what we have learnt from hydrodynamical simulations...
1995-07-07
2015-06-24
[ "astro-ph" ]
M.B. Davies, W. Benz
astro-ph/9507029
The LMC Supersoft X-Ray Binary RX J0513.9-6951
A detailed analysis of simultaneous photometric and spectroscopic observations of the optical counterpart of the LMC "supersoft" X-ray source RX J0513.9-6951 (identified with HV 5682) is presented. The spectrum is dominated by He II emission lines and H + He II blends; no He I is observed but several higher ionization ...
1995-07-07
2015-06-24
[ "astro-ph" ]
David Crampton, J.B. Hutchings, A.P. Cowley, P.C. Schmidtke, T.K. McGrath, D. O'Donoghue and M.K. Harrop-Allin
astro-ph/9507024
Constraining Peaks in Gaussian Primordial Density Fields: an Application of the Hoffman-Ribak Method
We develop an algorithm for setting up initial Gaussian random density and velocity fields containing one or more peaks or dips, in an arbitrary cosmological scenario. The intention is to generate appropriate initial conditions for cosmological N-body simulations that focus on the evolution of the progenitors of the pr...
1995-07-07
2015-06-24
[ "astro-ph" ]
Rien van de Weygaert and Edmund Bertschinger
astro-ph/9507019
Galaxy clusters and microwave background anisotropy
Previous estimates of the microwave background anisotropies produced by freely falling spherical clusters are discussed. These estimates are based on the Swiss-Cheese and Tolman-Bondi models. It is proved that these models give only upper limits to the anisotropies produced by the observed galaxy clusters. By using sph...
1995-07-06
2015-06-24
[ "astro-ph" ]
V. Quilis, J.M. Ibanez and D. Saez (Univ. Valencia, Dpto. Astronomia y Astrofisica)
astro-ph/9507021
Spherical Redshift Distortions
Peculiar velocities induce apparent line of sight displacements of galaxies in redshift space, distorting the pattern of clustering in the radial versus transverse directions. On large scales, the amplitude of the distortion yields a measure of the dimensionless linear growth rate $\beta \approx \Omega^{0.6}/b$, where ...
1995-07-06
2015-06-24
[ "astro-ph" ]
A. J. S. Hamilton and M. Culhane
astro-ph/9507018
Multiplicity among T Tauri stars in OB and T associations: Implications for binary star formation
We present first results of a survey for companions among X-ray selected pre-main sequence stars, most of them being weak-line T Tauri stars (WTTS). These T Tauri stars have been identified in the course of optical follow-up observations of sources from the ROSAT All Sky Survey associated with star forming regions. The...
1995-07-06
2016-08-30
[ "astro-ph" ]
Wolfgang Brandner, Juan M. Alcala, Michael Kunkel, Andrea Moneti, and Hans Zinnecker
astro-ph/9507017
Star Cluster Evolution, Dynamical Age Estimation and the Kinematical Signature of Star Formation
We use N-body integration to follow the evolution of clusters of 200 binary systems with different initial half mass radii $R_{0.5}$. We also simulate single-star clusters. All clusters evolve according to the same $n(t)$ curve, where $n(t)$ is the number density of stars in the central 2~pc sphere at time $t$. $n(t)$ ...
1995-07-06
2015-06-24
[ "astro-ph" ]
Pavel Kroupa
astro-ph/9507020
Getting the Measure of the Flatness Problem
The problem of estimating cosmological parameters such as $\Omega$ from noisy or incomplete data is an example of an inverse problem and, as such, generally requires a probablistic approach. We adopt the Bayesian interpretation of probability for such problems and stress the connection between probability and informati...
1995-07-06
2010-04-06
[ "astro-ph", "bayes-an" ]
Guillaume Evrard (Universite Montpellier II, France and Queen Mary and Westfield College, London), Peter Coles (Queen Mary and Westfield College, London)
astro-ph/9507022
Redshift Distortions and Omega in IRAS Surveys
Redshift space distortions on large scales can be used to measure the linear growth rate parameter $\ff \approx \Omega^{0.6}/b$. I report here measurements of such distortions in the IRAS 2 Jy, 1.2 Jy, and QDOT redshift surveys, finding $\ff = 0.69^{+ .21}_{- .19}$ from a merged QDOT plus 1.2 Jy catalogue. Unfortunatel...
1995-07-06
2008-02-03
[ "astro-ph" ]
A. J. S. Hamilton
astro-ph/9507016
Secondary Infall: Theory {\it Versus} Simulations
The applicability of the highly idealized secondary infall model to `realistic' initial conditions is investigated. The collapse of proto-halos seeded by $3\sigma$ density perturbations to an Einstein--de Sitter universe is studied here for a variety of scale-free power spectra with spectral indices ranging from $n=1$ ...
1995-07-05
2009-10-28
[ "astro-ph" ]
Saleem Zaroubi, Avi Naim, and Yehuda Hoffman
astro-ph/9507015
Omega from the COBE-DMR anisotropy maps
We have made a likelihood statistical analysis of the angular correlations in the {\it COBE}-DMR two-year sky maps by Monte Carlo simulation of the temperature fluctuations. We assume an open universe and consider as primordial power spectrum the Harrison-Zeldovich one, $P(k)=Ak$. We find that the flatness of the unive...
1995-07-05
2015-06-24
[ "astro-ph" ]
L. Cayon, E. Martinez-Gonzalez, J.L. Sanz, N. Sugiyama, S. Torres
astro-ph/9507014
THE CANADA-FRANCE REDSHIFT SURVEY V: Global Properties of the Sample
The photometric and spectroscopic data of the CFRS survey of objects with 17.5 < I_{AB} < 22.5 are combined and analysed. The overall completeness is 85%. The redshift histogram of the sample is presented for 591 field galaxies with secure redshifts. The median redshift is z = 0.56, and the highest redshift observed is...
1995-07-05
2016-08-30
[ "astro-ph" ]
David Crampton, O. Le Fevre, S.J. Lilly and F. Hammer
astro-ph/9507009
A method for subtracting foregrounds from multi-frequency CMB sky maps
An improved method for subtracting contaminants from Cosmic Microwave Background (CMB) sky maps is presented, and used to estimate how well future experiments will be able to recover the primordial CMB fluctuations. We find that the naive method of subtracting foregrounds (such as dust emission, synchrotron radiation, ...
1995-07-04
2015-06-24
[ "astro-ph" ]
Max Tegmark and George Efstathiou
astro-ph/9507012
THE CANADA-FRANCE REDSHIFT SURVEY III: "Single Emission Line" Objects, Analysis of Repeat Observations, and Spectroscopic Identifications in the 1415+52 and 2215+00 Fields
This paper is one of a series describing the Canada-France Redshift Survey (CFRS). It is shown how the shape of the continuum around the emission line can be used to distinguish between [OII] 3727 at z > 0.76 and H$\alpha$ at low redshift in spectra for which only a single isolated emission line is visible. Based on th...
1995-07-04
2009-10-28
[ "astro-ph" ]
S.J. lilly, F. Hammer, O. Le Fevre and David Crampton
astro-ph/9507011
THE CANADA-FRANCE REDSHIFT SURVEY II: Spectroscopic Program; Data for the 0000-00 and 1000+25 Fields
This paper describes the methods used to obtain the spectroscopic data and construct redshift catalogs for the Canada-France deep Redshift Survey (CFRS). The full data set consists of more than one thousand spectra, of objects with 17.5 < I_{AB} < 22.5, obtained from deep multi-slit data with the MARLIN and MOS-SIS spe...
1995-07-04
2016-08-30
[ "astro-ph" ]
O. Le Fevre, David Crampton, S.J. Lilly, F. Hammer and L. Tresse
astro-ph/9507013
THE CANADA-FRANCE REDSHIFT SURVEY IV: Spectroscopic Selection Effects and 0300+00 Field Spectroscopic Data
Possible surface brightness selection effects in the redshift catalogs of the Canada-France Redshift Survey are investigated through comparisons of subsamples of the data. Our analyses demonstrate that the securing of redshifts is independent of possible biases arising from surface brightness effects and/or differing g...
1995-07-04
2009-10-28
[ "astro-ph" ]
F. Hammer, David Crampton, O. Le Fevre and S.J. Lilly
astro-ph/9507007
Observational Evidence for Weak Gravitational Lensing by Large Scale Structure
A single very deep $10'$ field has been imaged to $r \sim 26$. There are 2682 galaxies with $23 \le r \le 26$ with a size significantly larger than the seeing disk in the field. After correcting for telescope aberrations, possible guiding errors, and signal degradation due to seeing, I find a polarization signal of amp...
1995-07-04
2007-05-23
[ "astro-ph" ]
Jens Verner Villumsen (Max Planck Institute fur Astrophysik, Garching, Germany)
astro-ph/9507008
The Dark Matter, Gas and Galaxy Distributions in Abell 2218: A Weak Gravitational Lensing and X-ray Analysis
We report on the detection of dark matter in the cluster Abell 2218 using the weak gravitational distortion of background galaxies. We find a highly significant, coherent detection of the distortion in the images of the background galaxies. The inferred 2D mass distribution has a peak that is coincident with the optica...
1995-07-04
2009-10-28
[ "astro-ph" ]
G. Squires, N. Kaiser, A. Babul, G. Fahlman, D. Woods, D. M. Neumann, and H. B\"ohringer
astro-ph/9507004
ROSAT observations of PSR 2334+61 in the supernova remnant G114.3+0.3
We report on the observation of PSR 2334+61 in the soft X-ray domain with ROSAT. Assuming a power-law spectrum $dN/dE\propto E^{-\alpha}$ with photon-index $\alpha=2$ we derive an X-ray flux of $f_x=(7.1 \pm 0.2) \times 10^{-14} \hbox{erg s}^{-1}\hbox{cm}^{-2}$ within the $0.1$--$2.4$ keV energy range. An upper limit f...
1995-07-04
2007-05-23
[ "astro-ph" ]
W.Becker, K.T.S.Barzier and J.Tr\"umper
astro-ph/9507005
Velocity correlation tensor and substructure's statistics around density peaks
We derive the conditional probability distribution of the peculiar velocity around a peak of given overdensity in a Gaussian density field. This distribution characterizes the shear field around local, isolated density peaks. We use the moments of the velocity distribution to study the spatial distribution of the escap...
1995-07-04
2007-05-23
[ "astro-ph" ]
V. Antonuccio-delogu and S. Colafrancesco
astro-ph/9507010
The CANADA-FRANCE REDSHIFT SURVEY I: Introduction to the Survey, Photometric Catalogs and Surface Brightness Selection Effects
The Canada-France Redshift Survey has been undertaken to provide a large well-defined sample of faint galaxies at high redshift in which the selection criteria match as closely as possible those of samples of nearby galaxies. The survey is designed to have a median redshift of z ~ 0.6 corresponding to a look-back time ...
1995-07-04
2009-10-28
[ "astro-ph" ]
S.J. Lilly, O. Le Fevre, David Crampton, F. Hammer and L. Tresse
astro-ph/9507006
Cold Plus Hot Dark Matter Cosmology in the Light of Solar and Atmospheric Neutrino Oscillations
We explore the implications of possible neutrino oscillations, as indicated by the solar and atmospheric neutrino experiments, for the cold plus hot dark matter scenario of large scale structure formation. We find that there are essentially three distinct schemes that can accommodate the oscillation data and which also...
1995-07-04
2008-11-26
[ "astro-ph", "hep-ph" ]
K.S. Babu, R.K. Schaefer, and Q. Shafi
astro-ph/9507001
A General Analytic Formula for the Spectral Index of the Density Perturbations produced during Inflation
The standard calculation of the spectrum of density perturbations produced during inflation assumes that there is only one real dynamical degree of freedom during inflation. However, there is no reason to believe that this is actually the case. In this paper we derive general analytic formulae for the spectrum and spec...
1995-07-03
2009-10-09
[ "astro-ph", "gr-qc", "hep-ph" ]
Misao Sasaki and Ewan D. Stewart
astro-ph/9507003
Gauge Invariant Density and Temperature Perturbations in the Quasi-Newtonian Formulation
We give an improved formalism for calculating the evolution of density fluctuations and temperature perturbations in flat universes. Our equations are general enough to treat the perturbations in collisionless relics like massive neutrinos. We find this formulation to be simpler to use than gauge dependent and other ga...
1995-07-03
2011-05-12
[ "astro-ph", "hep-ph" ]
Robert K. Schaefer and Andrew A. de Laix
astro-ph/9507002
FRII Radio Sources in Rich Clusters of Galaxies
A sample of FRII radio sources in rich clusters of galaxies, both at high (z$\sim$0.5) and low (z$\sim$0) redshift, has been constructed to study the effect of environment on radio sources. Comparisons are made between the properties of FRII sources in cluster and non-cluster environments, and between X-ray clusters wi...
1995-07-03
2007-05-23
[ "astro-ph" ]
Lin Wan & Ruth A. Daly
astro-ph/9506147
The Destruction of a Compact Group of Galaxies
The very high apparent galaxy densities in Hickson compact groups (HCGs) should produce copious amounts of galaxy-galaxy interaction, if these groups are bound dynamical units. I examine the evidence for such interactions in HCG 94, a group of seven galaxies with an envelope of diffuse optical light and an extremely hi...
1995-07-02
2009-10-28
[ "astro-ph" ]
Rachel A. Pildis (UMich)
astro-ph/9506146
Characteristics of Cosmic Time
The nature of cosmic time is illuminated using Hamilton-Jacobi theory for general relativity. For problems of interest to cosmology, one may solve for the phase of the wavefunctional by using a line integral in superspace. Each contour of integration corresponds to a particular choice of time hypersurface, and each yie...
1995-07-01
2009-10-28
[ "astro-ph", "gr-qc", "hep-ph" ]
D. S. Salopek
astro-ph/9506142
Dynamical and radiative properties of astrophysical supersonic jets I. Cocoon morphologies
We present the results of a numerical analysis of the propagation and interaction of a supersonic jet with the external medium. We discuss the motion of the head of the jet into the ambient in different physical conditions, carrying out calculations with different Mach numbers and density ratios of the jet to the exter...
1995-06-30
2008-02-03
[ "astro-ph" ]
S. Massaglia, G. Bodo, A. Ferrari (Osservatorio Astronomico di Torino, Italy)
astro-ph/9506145
Discovery of a Large Gravitational Arc in the X-ray Cluster A2280
This Letter presents the serendipitous discovery of a large arc in an X-ray selected cluster detected in the Rosat North Ecliptic Pole (NEP) survey. The cluster, associated with Abell 2280, is identified as the optical counterpart of the X-ray source RXJ 1743.5+6341. This object is a medium--distant z=0.326 and luminou...
1995-06-30
2007-05-23
[ "astro-ph" ]
I. M. Gioia, J. P. Henry, G. A. Luppino, D. I. Clowe, H. Boehringer, U. G. Briel, W. Voges, J.P. Huchra, H. MacGillivray (Institute for Astronomy, University of Hawaii,USA; Istituto di Radioastronomia del CNR, Bologna, Italy; Max-Planck-Institut fuer Extraterrestrische Physik, Garching bei Muenchen, Federal Rep...
astro-ph/9506140
The Optical Variability of QSO's
The long-term variability of a sample of 486 optically selected QSOs in the fields of the SA94, SA57 and SGP has been studied. The relations of variability with luminosity and redshift have been investigated by means of statistical estimators that are ``robust'' and allow at the same time to eliminate the influence of ...
1995-06-30
2007-05-23
[ "astro-ph" ]
S. Cristiani, S. Trentini, F. La Franca, I. Aretxaga, P. Andreani, R. Vio, A. Gemmo
astro-ph/9506144
Action Principle Solutions For Galaxy Motions Within 3000 Km/s
The numerical action variational principle is used to find fully nonlinear solutions for the orbits of the mass tracers given their present redshifts and angular positions and the cosmological boundary condition that the peculiar velocities are small at high redshift. A solution predicts the distances of the mass trace...
1995-06-30
2009-10-28
[ "astro-ph" ]
Edward J. Shaya, P.J.E. Peebles, & R. Brent Tully
astro-ph/9506141
Spatial and Luminosity Properties of the Perseus-Pisces Redshift Survey
We analyze the spatial and the luminosity properties of the Perseus-Pisces redshift survey. We find that the two point correlation function (CF) $\Gamma(r)$ is a power law up to the sample effective depth ($\sim 30 h^{-1}Mpc$), showing the fractal nature of the galaxy distribution in this catalog. The fractal dimension...
1995-06-30
2017-04-26
[ "astro-ph" ]
F. Sylos Labini, M. Montuori and L. Pietronero
astro-ph/9506143
Statistics of N-Body Simulations. III. Unequal Masses
We describe results from large numbers of $N$-body simulations containing from $250$ to $1000$ stars each. The distribution of stellar masses is a power law, and the systems are isolated. While the collapse of the core exhibits the expected segregation of different masses, we find that the post-collapse evolution is, a...
1995-06-30
2015-06-24
[ "astro-ph" ]
Mirek Giersz and Douglas C. Heggie
astro-ph/9506138
Galactic jet sources and the AGN connection
In order to further test our hypothesis that jets and disk around compact accreting objects are symbiotic features we investigate the newly discovered superluminal galactic radio jets GRS 1915+105 and GRO J1655-40 and the two famous galactic radio jets 1E1740-2942 and SS 433 within the framework of our couple jet/disk ...
1995-06-29
2007-05-23
[ "astro-ph" ]
Heino Falcke and Peter L. Biermann
astro-ph/9506139
Multiwavelength Energy Distributions and Bolometric Luminosities of the 12--Micron Galaxy Sample
Aperture photometry from our own observations and the literature is presented for the 12\um\ Galaxies in the near infrared J, H and K bands and, in some cases, in the L band. These data are corrected to ``total'' near--infrared magnitudes, (with a typical uncertainty of 0.3 magnitudes) for a direct comparison with our ...
1995-06-29
2009-10-28
[ "astro-ph" ]
Luigi Spinoglio (IFSI), Matthew A. Malkan & Brian Rush (UCLA), and Luis Carrasco & Else Recillas-Cruz (UNAM)
astro-ph/9506133
Formation, Propagation, and Decay of Coherent Pulses of Solar Cosmic Rays
We have performed numerical simulations of the interplanetary transport of solar cosmic rays. The particles form a coherent pulse within $\sim0.01$ AU after their injection. The gradual decrease of a pulse's speed and anisotropy can be understood in terms of an equilibrium between pitch-angle scattering and focusing. T...
1995-06-28
2015-06-24
[ "astro-ph" ]
D. Ruffolo and T. Khumlumlert (Chulalongkorn U., Bangkok)
astro-ph/9506136
The Infrared Diameter -- Velocity Dispersion Relation for Elliptical Galaxies
Using single channel infrared photometry from the literature, a provisional K-band diameter--velocity dispersion relation for elliptical galaxies in the Coma and Virgo clusters is derived. The Coma cluster relation has \~1.5 times lower scatter at K than in B or V. Excluding 4 outliers, the RMS scatter at K for 24 gala...
1995-06-28
2009-10-28
[ "astro-ph" ]
Michael D. Gregg (IGPP/LLNL)
astro-ph/9506134
Three-point correlation function of galaxy clusters in cosmological models: a strong dependence on triangle shape
In this paper, we use large $\pppm$ N-body simulations to study the three-point correlation function $\zeta$ of clusters in two theoretical models. The first model (LCDM) is a low-density flat model of $\Omega_0=0.3$, $\Lambda_0=0.7$ and $h=0.75$, and the second model (PIM) is an Einstein-de-Sitter model with its linea...
1995-06-28
2015-06-24
[ "astro-ph" ]
Y.P. Jing (MPA), G. Boerner (MPA), R. Valdarnini (SISSA)
astro-ph/9506137
On The Jets Associated with Galactic Superluminal Sources
Recent observations of GRS 1915+105 and GRO J1655+40 reveal superluminal motions in Galactic sources. This letter examines the physical conditions within these Galactic sources, their interaction with their environment, their possible formation, and contrasts them with their extragalactic counterparts. In particular, e...
1995-06-28
2009-10-28
[ "astro-ph" ]
Amir Levinson and Roger Blandford
astro-ph/9506132
Primordial Magnetic Fields in False Vacuum Inflation
We show that, during false vacuum inflation, a primordial magnetic field can be created, sufficiently strong to seed the galactic dynamo and generate the observed galactic magnetic fields. Considering the inflaton dominated regime, our field is produced by the Higgs-field gradients, resulting from a grand unified phase...
1995-06-28
2010-11-30
[ "astro-ph", "hep-ph" ]
A. C. Davis and K. Dimopoulos
astro-ph/9506135
The Nature of Plerions Surrounding Soft Gamma-Ray Repeaters
Compact steady sources of X-ray emission have been detected at the positions of at least two soft gamma-ray repeaters (SGRs). These sources have been interpreted as synchrotron nebulae powered by the neutron star that is causing the bursts. We explore a plerion model for the sources surrounding SGRs where the steady ob...
1995-06-28
2009-10-28
[ "astro-ph" ]
Alice K. Harding (NASA GSFC)
astro-ph/9506148
The Effects of Starbursts and Low-Surface-Brightness Galaxies on Faint Galaxy Models
We present models predicting the magnitude, redshift, and color distributions of field galaxies. We explore whether a fading starburst scenario can account for the observations of faint blue galaxies. We marginally rule out a starburst scenario with a local IMF because the models predict too many nearby faint galaxies ...
1995-06-28
2009-10-28
[ "astro-ph" ]
B. A. McLeod and M. J. Rieke
astro-ph/9506129
QSO's from Galaxy Collisions with Naked Black Holes
In the now well established conventional view (see Rees [1] and references therein), quasi-stellar objects (QSOs) and related active galactic nuclei (AGN) phenomena are explained as the result of accretion of plasma onto giant black holes which are postulated to form via gravitational collapse of the high density regio...
1995-06-27
2009-10-28
[ "astro-ph" ]
M. Fukugita and E. L. Turner
astro-ph/9506128
ROSAT observations of radio-selected BL Lac objects
ROSAT observations of a homogeneous sample of radio--selected BL Lac objects are presented. Results of a detailed spectral analysis in the soft 0.1-2.0 keV energy range are discussed and compared with similar previously published results. The X--ray spectral shape is discussed in relation to the overall energy distribu...
1995-06-27
2015-06-24
[ "astro-ph" ]
Andrea Comastri, Silvano Molendi and Gabriele Ghisellini
astro-ph/9506127
Ising Model formulation of Large Scale Dynamics: Universality in the Universe
The partition function of a system of galaxies in gravitational interaction can be cast in an Ising Model form, and this reformulated via a Hubbard--Stratonovich transformation into a three dimensional stochastic and classical scalar field theory, whose critical exponents are calculable and known. This allows one to {\...
1995-06-27
2007-05-23
[ "astro-ph", "gr-qc" ]
J. Perez--Mercader, T. Goldman, D. Hochberg and R. Laflamme
astro-ph/9506130
Photon Splitting in Magnetar Models of Soft Gamma Repeaters
The recent association of soft gamma repeaters (SGRs) with counterparts in other wavebands has sparked much interest in these sources. One of the recent models for these objects is that they originate in the environs of neutron stars with fields much stronger than the quantum critical field \teq{B_{cr}=4.413\times 10^{...
1995-06-27
2009-10-28
[ "astro-ph" ]
M. G. Baring and A. K. Harding
astro-ph/9506131
Big Bang Nucleosynthesis: An Update
WThe current status of big bang nucleosynthesis is reviewed with an emphasis on the comparison between the observational determination of the light element abundances of \D, \he3, \he4 and \li7 and the predictions from theory. In particular, we present new analyses for \he4 and \li7. Implications for physics beyond the...
1995-06-27
2009-09-15
[ "astro-ph", "hep-ph" ]
Keith A. Olive and Sean T. Scully
astro-ph/9506122
The purpose of astronomy
This is a presentation of the purpose of astronomy in the context of modern society. After exposing two misconceptions about astronomy, I detail its role in five domains, certified knowledge, incorporated abilities, innovations, collective goods, and popular science; with each domain is associated an institution, an in...
1995-06-26
2009-10-28
[ "astro-ph" ]
Emmanuel Davoust (OMP, Toulouse, France)
astro-ph/9506123
Visual Search for Galaxies near the Northern Crossing of the Supergalactic plane by the Milky Way
We have visually examined twelve Palomar red Plates for galaxies at low Galactic latitude b, where the Supergalactic Plane (SGP) is crossed by the Galactic Plane (GP), at Galactic longitude l ~135 degrees. The catalogue consists of 2575 galaxy candidates, of which 462 have major axis diameters d >= 0.8 arc min (uncorre...
1995-06-26
2015-06-24
[ "astro-ph" ]
G. K. T. Hau, H. C. Ferguson, O. Lahav, D. Lynden-Bell
astro-ph/9506125
The Physical State of the Intergalactic Medium or Can We Measure Y?
We present an argument for a {\it lower limit} to the Compton-$y$ parameter describing spectral distortions of the cosmic microwave background (CMB). The absence of a detectable Gunn-Peterson signal in the spectra of high redshift quasars demands a high ionization state of the intergalactic medium (IGM). Given an ioniz...
1995-06-26
2015-06-24
[ "astro-ph" ]
J.G. Bartlett, D. Barbosa, A. Blanchard (Observatoire de Strasbourg)
astro-ph/9506121
Software for producing trichromatic images in astronomy
We present a software package for combining three monochromatic images of an astronomical object into a trichromatic color image. We first discuss the meaning of "true" colors in astronomical images. We then describe the different steps of our method, choosing the relevant dynamic intensity range in each filter, invent...
1995-06-26
2009-10-28
[ "astro-ph" ]
Sebastien Morel, Emmanuel Davoust (OMP, Toulouse, France)
astro-ph/9506124
The HST Quasar Absorption Line Key Project VII. Absorption Systems at $z_{\rm abs} \leq 1.3$
We present evidence that clumps of \lya lines are physically associated with about half of the extensive metal-line systems (absorption systems with four or more observed metal-line species) found in this paper, demonstrate that all four \lylimit systems discussed here correspond to extensive metal-line absorption syst...
1995-06-26
2009-10-28
[ "astro-ph" ]
John N. Bahcall, Jacqueline Bergeron, Alec Boksenberg, George F. hartig, Buell T. Jannuzi, Sofia Kirhakos, W. L. W. Sargent, Blair D. Savage, Donald P.Schneider, David A. Turnshek, Ray J. Weymann, and Arthur M. Wolfe
astro-ph/9506126
ASCA observations of high redshift quasars
ASCA observations of 4 high redshift radio--loud quasars with 1.44$<$z$<$3.21 are presented. The spectral analysis for three of them (PKS 0332-403, PKS 0537-286, PKS 2149-306) reveals that their X-ray continuum emission is well represented by a simple power--law model plus absorption with photon indices of $\Gamma =1.9...
1995-06-26
2007-05-23
[ "astro-ph" ]
J.Siebert, M.Matsuoka, W.Brinkmann, M.Cappi, T.Mihara, T.Takahashi
astro-ph/9506120
Measuring Hubble's Constant in our Inhomogeneous Universe
Recent observations of Cepheids in the Virgo cluster have bolstered the evidence that supports a Hubble constant in 70-90 km/s/Mpc range. This evidence, by and large, probes the expansion of the Universe within 100 Mpc. We investigate the possibility that the expansion rate within this region is systematically higher t...
1995-06-25
2015-06-24
[ "astro-ph" ]
Xiangdong Shi, Lawrence M. Widrow, L. Jonathan Dursi (Queen's University, Kinsgton, Ontario)
astro-ph/9506119
Propagation of Ultra High Energy Protons over Cosmological Distances and Implications for Topological Defect Models
We describe the results of a hybrid matrix--Monte Carlo calculation of cascading of UHE cosmic rays and $\gamma$-rays through the cosmic background radiation fields over cosmological distances. We calculate the $\gamma$-ray and neutrino emission that results from the cascade, as well as the effect of cascading on the p...
1995-06-23
2009-10-28
[ "astro-ph" ]
R. J. Protheroe and P. A. Johnson
astro-ph/9506118
A Break in the Highest Energy Cosmic Ray Spectrum: A Signature of New Physics?
Recent experimental data from the Fly's Eye and the Akeno array seem to indicate significant structure in the ultrahigh energy cosmic ray spectrum above $10^{18}\eV$. A statistically significant dip has been established at about $5\times10^{18}\eV$. In addition, each experiment observed a different superhigh energy eve...
1995-06-23
2009-10-28
[ "astro-ph" ]
G.Sigl, S.Lee, D.N.Schramm, and P.Bhattacharjee
astro-ph/9506116
The Globular Clusters in M87: A Bimodal Colour Distribution
We present $V$ and $I$ photometry for $\sim 150$ globular clusters with $20 < V < 27$ $\sim 2.5$ arcmin from the centre of M87, the cD galaxy in the Virgo cluster. The data were acquired with the Hubble Space Telescope which, with effective resolution 0.1 arcsec, allows us for the first time to distinguish between glob...
1995-06-22
2015-06-24
[ "astro-ph" ]
Rebecca A.W. Elson and Basilio X. Santiago
astro-ph/9506115
VLBI Observations of a Complete Sample of Radio Galaxies. VI. The Two FR-I Radio Galaxies B2 0836+29 and 3C465
We present 5 GHz global VLBI observations of the two Fanaroff Riley Type I radio galaxies B2 0836+29 and 3C465 (2335+26). For 3C465 we present also 1.7 GHz and 8.4 GHz global VLBI data. In addition VLA observations were used to obtain arsecond resolution continuum and polarization maps at 5 GHz. Both sources are very a...
1995-06-22
2015-06-24
[ "astro-ph" ]
T. Vneturi, C. Castaldini, W.D. Cotton, L. Feretti, G. Giovannini, L. Lara, J.M. Marcaide, A.E. Wehrle
astro-ph/9506114
First Observation of Parallax in a Gravitational Microlensing Event
We present the first detection of parallax effects in a gravitational microlensing event. Parallax in a gravitational microlensing event observed only from the Earth appears as a distortion of the lightcurve due to the motion of the Earth around the Sun. This distortion can be detected if the event duration is not much...
1995-06-22
2009-10-28
[ "astro-ph" ]
C. Alcock, R.A. Allsman, D. Alves, T.S. Axelrod, D.P. Bennett, K.H. Cook, K.C. Freeman, K. Griest, J. Guern, M.J. Lehner, S.L. Marshall, B.A. Peterson, M.R. Pratt, P.J. Quinn, A.W. Rodgers, C.W. Stubbs, and W. Sutherland (The MACHO Collaboration)
astro-ph/9506117
Discovery of a faint optical jet in 3C 120
We report the detection of an optical jet in the nearby Seyfert 1 radio galaxy 3C 120. The optical jet coincides with the well-known radio jet and emits continuum radiation (B,V',I) with a radio-to-optical spectral index of 0.65. There are no clear optical counterparts to the radio knots, although the optical condensat...
1995-06-22
2008-02-03
[ "astro-ph" ]
J. Hjorth, M. Vestergaard, A. N. Sorensen, F. Grundahl
astro-ph/9506113
The MACHO Project First Year LMC Results: The Microlensing Rate and the Nature of the Galactic Dark Halo
The MACHO collaboration reports on the analysis of our first year LMC data, 9.5 million light curves with an average of 235 observations each. Automated selection procedures give 3 events consistent with microlensing. We evaluate our experimental detection efficiency using a range of Monte- Carlo simulations. Using a `...
1995-06-21
2009-10-28
[ "astro-ph", "hep-ph" ]
C.Alcock, R.A.Allsman, T.S.Axelrod, D.P.Bennett, K.H.Cook, K.C.Freeman, K.Griest, J.A.Guern, M.J.Lehner, S.L.Marshall, H.-S.Park, S.Perlmutter, B.A.Peterson, M.R.Pratt, P.J.Quinn, A.W.Rodgers, C.W.Stubbs, W.Sutherland (The MACHO Collaboration)
astro-ph/9506112
Pair annihilation radiation from relativistic jets in gamma-ray blazars
The contribution of the pair annihilation process in relativistic electron-positron jets to the gamma-ray emission of blazars is calculated. Under the same assumptions as for the calculation of the yield of inverse Compton scattered accretion disk radiation (Dermer and Schlickeiser 1993) we calculate the emerging pair ...
1995-06-21
2011-05-23
[ "astro-ph" ]
M. Boettcher, R. Schlickeiser (MPI f. Radioastronomie, Bonn)
astro-ph/9506109
Self-Consistent Evolution of Ring Galaxies
Ring galaxies are commonly known as objects where a burst of star formation was triggered by a close encounter with an intruder, maybe a satellite galaxy. BVRI CCD observations of five ring galaxies have been performed. Here we present the results of a self-consistent approach to reproduce their observed morphology and...
1995-06-21
2009-10-28
[ "astro-ph" ]
Paola Mazzei, Anna, Curir, Carlotta Bonoli
astro-ph/9506111
Spectropolarimetry of the nova-like variable V1315 Aql
We present spectropolarimetric observations of the eclipsing nova-like variable V1315 Aql, obtained with the aim of determining whether the single-peaked uneclipsed lines observed in this and related nova-likes are the result of disc emission scattered into the line of sight by the wind. The data show linear polarizati...
1995-06-21
2015-06-24
[ "astro-ph" ]
V.S. Dhillon, R.G.M. Rutten
astro-ph/9506103
The Metallicity Dependence of the CO-to-H$_2$ Conversion Factor from Observations of Local Group Galaxies
High-resolution CO maps of 9 molecular clouds in IC 10 are combined with the new measurement of the distance to this nearby metal poor galaxy to measure accurately the CO-to-H2 conversion factor. The result for IC 10 is combined with published data for four other Local Group galaxies (M31, M33, NGC 6822, the SMC) to tr...
1995-06-20
2010-04-06
[ "astro-ph" ]
C. D. Wilson
astro-ph/9506104
The Star Formation Histories and Efficiencies of Two Giant HII Regions in M33
$UBV$ photometry is used to re-identify the OB associations which power the two most luminous HII regions in M33, NGC 604 and NGC 595. There is a significant difference (2-3 Myr) in the ages of the most recent star formation episode in these two regions, while NGC 595 also has undergone a prior episode of star formatio...
1995-06-20
2009-10-28
[ "astro-ph" ]
C. D. Wilson and B. C. Matthews
astro-ph/9506110
The Cluster Distribution as a Test for Dark Matter Models. II: The Dipole Structure
We study the dipole for a redshift sample of Abell/ACO clusters. To elucidate the constraints it places on dark matter models, we use numerical simulations based on the Zel'dovich approximation. We run 20 realizations of each of six different dark matter models: four of these have a density parameter $\Omega_0=1$, whil...
1995-06-20
2015-06-24
[ "astro-ph" ]
P. Tini Brunozzi, S. Borgani, M. Plionis, L. Moscardini, P. Coles
astro-ph/9506101
Object DUO 2: A New Binary Lens Candidate
We present the light curve of an unusual variable object, DUO 2, detected during the search for microlensing events by the DUO project. The star remained stable for more than 150 days before it brightened by more than two magnitudes in 6 days in the B and R bands. The light curves are achromatic during the variability....
1995-06-20
2007-05-23
[ "astro-ph" ]
C. Alard, S. Mao, J. Guibert
astro-ph/9506107
Are Galaxies Optically Thin to Their Own Lyman Continuum Radiation? II. NGC 6822
Halpha and UBV photometry of NGC 6822 are used to study the distribution of OB stars and HII regions in the galaxy and to determine whether individual regions of the galaxy are in a state of ionization balance. Four distinct components of the Halpha emission (bright, halo, diffuse and field) differentiated by their sur...
1995-06-20
2009-10-28
[ "astro-ph" ]
K. Patel and C. D. Wilson
astro-ph/9506106
Are Galaxies Optically Thin to Their Own Lyman Continuum Radiation? I. M33
Halpha and UBV photometry of the inner kpc of M33 are used to study the distribution of OB stars and HII regions in the galaxy and to determine whether individual regions of the galaxy are in a state of ionization balance. Based on the surface brightness of the Halpha emission, we identify three distinct ionized gas en...
1995-06-20
2009-10-28
[ "astro-ph" ]
K. Patel and C. D. Wilson
astro-ph/9506100
The Significance of the Cosmic Virial Theorem
We discuss the development and physics of the cosmic virial theorem and its traditional application as an indicator of the cosmic mean density. The standard result that the density must be sub-critical relies on the assumption that the galaxy three-point correlation function accurately describes the mass distribution a...
1995-06-20
2011-05-23
[ "astro-ph" ]
James G. Bartlett and Alain Blanchard (Observatoire de Strasbourg)
astro-ph/9506108
The extinction by dust in the outer parts of spiral galaxies
To investigate the distribution of dust in Sb and Sc galaxies we have analyzed near-infrared and optical surface photometry for an unbiased sample of 37 galaxies. Since light in the $K$-band is very little affected by extinction by dust, the $B-K$ colour is a good indicator of the amount of extinction, and using the co...
1995-06-20
2007-05-23
[ "astro-ph" ]
R.F. Peletier, E.A. Valentijn, A.F.M. Moorwood, W. Freudling, J.H. Knapen and J.E. Beckman
astro-ph/9506102
Gravitational Lensing and Anisotropies of CBR on the Small Angular Scales
We investigate the effect of gravitational lensing, produced by linear density perturbations, for anisotropies of the Cosmic Background Radiation (CBR) on scales of arcminutes. In calculations, a flat universe ($\Omega=1$) and the Harrison-Zel'dovich spectrum ($n=1$) are assumed. The numerical results show that on scal...
1995-06-20
2015-06-24
[ "astro-ph" ]
J.M. Liu, J.G. Gao
astro-ph/9506105
HST Star Counts at High Galactic Latitudes
We use star counts from 13 deep HST fields imaged with the {\it Wide Field Camera - 2} in order to constrain the amount of dark matter in the Galaxy that can be in the form of low-mass main sequence stars or white-dwarfs. Based on the number of red stars found in our fields, we exclude the possibility that more than 25...
1995-06-20
2015-06-24
[ "astro-ph" ]
Basilio X. Santiago, Gerard Gilmore, Rebecca A. W. Elson
astro-ph/9506099
Gamma-ray bursters as sources of cosmic rays
The little we do know of the physical conditions in gamma-ray bursters makes them conducive to the acceleration of high-energy cosmic rays, especially if they are at cosmological distances. We find that, with the observed statistics and fluxes of gamma-ray bursts, cosmological bursters may be an important source of cos...
1995-06-20
2008-11-26
[ "astro-ph", "hep-ph" ]
Mordehai Milgrom and Vladimir Usov (Weizmann Institute)
astro-ph/9506098
The Central Region in M100: Observations and Modeling
We present new high-resolution observations of the center of the late-type spiral M100 (NGC 4321) supplemented by 3D numerical modeling of stellar and gas dynamics, including star formation (SF). NIR imaging has revealed a stellar bar, previously inferred from optical and 21 cm observations, and an ovally-shaped ring-l...
1995-06-19
2010-04-21
[ "astro-ph" ]
J.H. Knapen, J.E. Beckman, C.H. Heller, I. Shlosman & R.S. de Jong
astro-ph/9506097
The OPAL Equation of State and Low Metallicity Isochrones
The Yale stellar evolution code has been modified to use the OPAL equation of state tables (Rogers 1994). Stellar models and isochrones were constructed for low metallicity systems ($-2.8 \le [Fe/H] \le -0.6$). Above $M\sim 0.7\,\msun$, the isochrones are very similar to those which are constructed using an equation of...
1995-06-19
2009-10-28
[ "astro-ph" ]
Brian Chaboyer and Yong --Cheol Kim
astro-ph/9506095
Deep optical galaxy counts with the Keck Telescope
We present faint galaxy counts from deep $VRI$ images obtained with the Keck Telescope. These images reach $R\sim27$ in median seeing FWHM $\sim 0.5$--0.6 arcsec and we detect a integrated galaxy number density of $7\times 10^{5}$ degree$^{-2}$, equivalent to $3\times 10^{10}$ galaxies in the observable Universe. In ad...
1995-06-17
2009-10-28
[ "astro-ph" ]
Ian Smail (OCIW), David W. Hogg (Caltech), Lin Yan (Caltech), and Judy Cohen (Caltech)
astro-ph/9506096
X-Ray Spectra of Z Sources
A simple, physically consistent model has been proposed that seeks to explain in a unified way the X-ray spectra and rapid X-ray variability of the so-called Z sources and other accreting neutron stars in low-mass systems. Here we summarize the results of detailed numerical calculations of the X-ray spectra of the Z so...
1995-06-17
2009-10-28
[ "astro-ph" ]
Dimitrios Psaltis (University of Illinois), Frederick K. Lamb (University of Illinois), and Guy S. Miller (Northwestern University)
astro-ph/9506090
ABELL 2163: Temperature, Mass, and Hydrostatic Equilibrium
Using ASCA data, we have measured the electron temperature in A2163 out to 1.5h^{-1} Mpc (10a_x) from the center, in three radial bins. The temperatures are 12.2+1.9-1.2 keV, 11.5+2.7-2.9 keV and 3.8+1.1-0.9 keV (90%) in the 0-3 a_x (0-3.5'), 3-6 a_x and 6-13 a_x spherical shells, respectively. Applying the hydrostatic...
1995-06-16
2009-10-28
[ "astro-ph" ]
M.Markevitch, R.Mushotzky, H.Inoue, K.Yamashita, A.Furuzawa, Y.Tawara
astro-ph/9506091
Open Cold Dark Matter Models
Motivated by recent developments in inflationary cosmology indicating the possibility of obtaining genuinely open universes in some models, we compare the predictions of cold dark matter (CDM) models in open universes with a variety of observational information. The spectrum of the primordial curvature perturbation is ...
1995-06-16
2015-06-24
[ "astro-ph" ]
Andrew R Liddle, David H Lyth, David Roberts and Pedro P T Viana
astro-ph/9506094
Big-Bang Nucleosynthesis and Galactic Chemical Evolution
Deuterium is the best indicator of the baryon density; however, only its present abundance is known (and only locally) and its chemical evolution is intertwined with that of $^3$He. Because galactic abundances are spatially heterogeneous, mean chemical-evolution models are not well suited for extrapolating the pre-sola...
1995-06-16
2009-10-28
[ "astro-ph" ]
Craig J. Copi, David N. Schramm, and Michael S. Turner
astro-ph/9506092
Blending of Light in Gravitational Microlensing Events
When there is more than one source of light along the line of sight to a gravitationally lensed object, the characteristics of the observed light curve are influenced by the presence of the light that is not lensed. In this paper we develop a formalism to quantify the associated effects. We find it useful to introduce ...
1995-06-16
2009-10-28
[ "astro-ph" ]
R. DiStefano, A. A. Esin
astro-ph/9506093
The environments of z<0.3 QSOs
We have carried out an investigation of the galaxy environments of low redshift ($z<0.3$) QSOs by cross-correlating the positions on the sky of X-ray-selected QSOs/AGN identified in the {\it Einstein} Medium Sensitivity Survey (EMSS) with those of $B_J<20.5$ galaxies in the APM galaxy catalogues. At $<5\,$arcmin, we fi...
1995-06-16
2015-06-24
[ "astro-ph" ]
R.J. Smith, B.J. Boyle, S.J. Maddox
astro-ph/9506086
ASCA PV observations of the Seyfert 1 galaxy MCG-6-30-15 : rapid variability of the warm absorber
We present a detailed re-analysis of the two {\it ASCA} Performance Verification observations of the nearby Seyfert 1 galaxy MCG-6-30-15. Confirming the results of Fabian et al. (1994), we find definite evidence for the {\sc O\,vii} and {\sc O\,viii} K-shell absorption edges of the warm absorber and a doubling of the w...
1995-06-14
2015-06-24
[ "astro-ph" ]
C.S. Reynolds, A.C. Fabian, K. Nandra, H. Inoue, H. Kunieda, K. Iwasawa
astro-ph/9506084
Inversions in astronomy and the SOLA method
This paper was presented at the Institute for Mathematics and its Applications workshop "Inverse problems in wave propagation" and will appear in the series IMA volumes (Springer). A brief overview of applications of inversions within astronomy is presented and also an inventory of techniques commonly in use. Most of t...
1995-06-14
2007-05-23
[ "astro-ph" ]
F.P. Pijpers
astro-ph/9506089
Spectroscopic Evidence That the Extreme Properties of IRAS F10214+4724 are due to Gravitational Lensing
The extreme bolometric luminosity of IRAS F10214+4724, and in particular the huge mass in molecular gas inferred from the CO line fluxes have led to suggestions that this is a giant galaxy in the process of formation. An arc-like structure and the closeness of a second object suggest, however, that gravitational lensin...
1995-06-14
2016-06-08
[ "astro-ph" ]
Stephen Serjeant, Mark Lacy, Steve Rawlings, Lindsay King, D.L. Clements
astro-ph/9506087
Discovery of an ultrasoft transient ROSAT AGN: WPVS007
We have identified the ROSAT source RX J0039.2-5117 with the previously almost unknown `narrow line' Seyfert 1 galaxy WPVS007 (z=0.028). The X-ray source displays quite unusual properties for an AGN. It was bright and ultrasoft in the ROSAT All-Sky Survey (RASS) and found at a level lower by a factor of ~ 400 in PSPC c...
1995-06-14
2007-05-23
[ "astro-ph" ]
D. Grupe, K. Beuermann, K. Mannheim, H.-C. Thomas, D. deMartino, and H.H. Fink
astro-ph/9506088
COBE-DMR-normalisation for inflationary flat dark matter models
The two-year COBE-DMR 53 and 90 GHz sky maps, in both galactic and ecliptic coordinates, are used to determine the normalisation of inflationary universe models with a flat global geometry and adiabatic density perturbations. The appropriately normalised cold and mixed dark matter models and cosmological constant domin...
1995-06-14
2015-06-24
[ "astro-ph" ]
R. Stompor, K.M. Gorski and A.J. Banday
astro-ph/9506085
Optical appearance of the gravitational lens system B0218+35.7
We present high-resolution CCD images (FWHM=0.6"-0.7") of the compact gravitational lens system B0218+35.7 obtained at the Nordic Optical Telescope. Using aperture and PSF photometry we detect the two closely separated (335 mas) components A and B as well as the lensing galaxy. In the optical B seems to be very much br...
1995-06-13
2016-06-08
[ "astro-ph" ]
F. Grundahl, J. Hjorth
astro-ph/9506083
Mergers and Galaxy Evolution (Sept94 Ringberg Workshop)
Galaxy merging is the late time manifestation of the galaxy formation process and likely significantly effects $z<1$ galaxies. A ``maximum reasonable rate'' model for merging finds a $\sim2$ mag K band increase in the luminosities of dwarf galaxies so that they contribute significantly to the faint counts, with spirals...
1995-06-13
2016-08-30
[ "astro-ph" ]
R. G. Carlberg
astro-ph/9506080
The Optical Content of the Error Box of GRS 1915+105
We report on deep photometry and spectroscopy of the objects detected in the ROSAT HRI X-ray error box of the hard X-ray transient, GRS 1915+105. The probable counterpart of this source has been detected, with a magnitude of 23.4 in the I band. The optical absorption ${\rm A}_{\rm V} = 28$ derived from the X-ray data i...
1995-06-13
2007-05-23
[ "astro-ph" ]
Michel Boer, Jochen Greiner, and Christian Motch
astro-ph/9506081
On the acceleration of Ultra High Energy Cosmic Rays in Gamma Ray Bursts
UHECRs are roughly isotropic and attain very large energies, $E \gtrsim 3\times 10^{20} \; eV$. Conventional models fail to explain both facts. I show here that acceleration of UHECRs in GRBs satisfies both observational constraints. Using M\'esz\'aros and Rees' (1994) model of GRBs as due to hyperrelativistic shocks, ...
1995-06-13
2009-10-28
[ "astro-ph" ]
Mario Vietri (Osservatorio Astronomico di Roma)
astro-ph/9506082
The Effect of Encounters on the Eccentricity of Binaries in Clusters
We derive analytical expressions for the change in the orbital eccentricity of a binary following a distant encounter with a third star on a hyperbolic or parabolic orbit. To establish the accuracy of these expressions, we present detailed comparisons with the results of direct numerical integrations of the equations o...
1995-06-13
2015-06-24
[ "astro-ph" ]
Douglas C. Heggie and Frederic A. Rasio
astro-ph/9506079
On the Global Stability of Magnetized Accretion Disks. II. Vertical and Azimuthal Magnetic Fields
We investigate the global stability of a differentially rotating fluid shell threaded by vertical and azimuthal magnetic fields to linear, axisymmetric perturbations. This system, which models a thick accretion disk in the vicinity of its midplane, is susceptible to the Velikhov-Chandrasekhar (VC) instability in the ab...
1995-06-13
2009-10-28
[ "astro-ph" ]
Charles Curry and Ralph E. Pudritz
astro-ph/9506075
The small-scale clustering power spectrum and relativistic decays
We present constraints on decaying-particle models in which an enhanced relativistic density allows an $\Omega=1$ Cold Dark Matter universe to be reconciled with acceptable values for the Hubble constant. Such models may contain extra small-scale power, which can have important consequences for enhanced object formatio...
1995-06-12
2015-06-24
[ "astro-ph" ]
S.J. McNally and J.A. Peacock
astro-ph/9506077
The Canada-France Redshift Survey VII: Optical counterparts of microJansky radiosources
Deep imaging and spectroscopy have been carried out for optical counterparts of a complete sample of S$>$16 $\mu$Jy radiosources during the course of the Canada-France Redshift Survey (CFRS). All 36 sources but two have been optically identified, and spectra have been obtained for 23 of them. The objects brighter than ...
1995-06-12
2015-06-24
[ "astro-ph" ]
F. Hammer, D. Crampton, O. Le Fevre, S. Lilly, T. Kenet
astro-ph/9506073
How much of the extreme luminosity of IRAS F10214+4724 can be attributed to gravitational lensing
\noindent The galaxy IRAS F10214+4724, discovered in a spectroscopic survey of a 0.2 Jy sample by Rowan-Robinson and collaborators in 1991, is significantly more luminous than any other known galaxy. Its bolometric luminosity is comparable to those of the most luminous quasars. Recent obsservations have revealed a cand...
1995-06-12
2015-06-24
[ "astro-ph" ]
Neil Trentham
astro-ph/9506078
Cygnus A and Other 3CR Sources in Cosmological Tests
Powerful extended radio galaxies like Cygnus A can be used for cosmological tests. The characteristic, time-independent length $D_*$ for several radio sources is calculated and compared to the average physical length for a sample of radio galaxies. The ratio of these two lengths as a function of redshift is used to con...
1995-06-12
2007-05-23
[ "astro-ph" ]
Erick J. Guerra & Ruth A. Daly