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astro-ph/9504025
Approximate input physics for stellar modelling
We present a simple and efficient, yet reasonably accurate, equation of state, which at the moderately low temperatures and high densities found in the interiors of stars less massive than the Sun is substantially more accurate than its predecessor by Eggleton, Faulkner & Flannery. Along with the most recently availabl...
1995-04-07
2015-06-24
[ "astro-ph" ]
O.R. Pols, C.A. Tout, P.P. Eggleton, Z. Han
astro-ph/9504026
The Nuclear Impact on Cosmology: The $H_0\hbox{-}\Omega$ Diagram
The \HOmega\ diagram is resurrected to dramatically illustrate the nature of the key problems in physical cosmology today and the role that nuclear physics plays in many of them. In particular it is noted that the constraints on \OmegaB\ from big bang nucleosynthesis do not overlap with the constraints on \OmegaVis\ no...
1995-04-07
2014-10-13
[ "astro-ph" ]
Craig J. Copi and David N. Schramm
astro-ph/9504023
An additional source of gas ionization in the extended narrow line region of NGC1068
The results of calculations of gas emission spectra with both central and extended sources of ionization have been compared to the ratio of line intensities observed in the extended narrow line region of NGC1068. The origin of an extended structure of anomalous strength in the $[OIII] \lambda 5007$ and $[NeV] \lambda 3...
1995-04-07
2007-05-23
[ "astro-ph" ]
L.S. Nazarova
astro-ph/9504016
RECONSTRUCTING POSITIONS AND PECULIAR VELOCITIES OF GALAXY CLUSTERS WITHIN 20000 Km/sec
Starting from the observed redshift distribution of a volume limited Abell/ACO cluster sample we use a 2-step procedure to recover their distances and peculiar velocities (assuming linear theory and linear biasing). The resulting 3D dipole is found to be 23\% less than the corresponding z-space one which leads to a val...
1995-04-06
2007-05-23
[ "astro-ph" ]
E. BRANCHINI and M. PLIONIS
astro-ph/9504018
The Statistics of Microlensing Light Curves: I. Amplification Probability Distributions
The passage of stars through the beam of a lensed quasar can induce violent fluctuations in its apparent brightness. The fluctuations observed in the Huchra lens, (2237+0305), are taken to be the first evidence of this ``microlensing'' occurring in lensing systems. Subsequent microlensing events observed in this system...
1995-04-06
2015-06-24
[ "astro-ph" ]
G.F. Lewis, M.J. Irwin
astro-ph/9504017
The proximity Effect on the Lyman alpha Forest due to a Foreground QSO
We present the results of our study on three close pairs of QSOs. Our results are consistent with the existence of a proximity effect due to the foreground QSO, but due to its weakness we can only reject the absence of such effect at approx. 1 sigma level. By modelling this proximity effect in terms of a simple photoio...
1995-04-06
2007-05-23
[ "astro-ph" ]
A. Fernandez-Soto, X.Barcons, R. Carballo, J.K. Webb
astro-ph/9504020
GALAXY DYNAMICS IN CLUSTERS
We use high resolution simulations to study the formation and distribution of galaxies within a cluster which forms hierarchically. We follow both dark matter and baryonic gas which is subject to thermal pressure, shocks and radiative cooling. Galaxy formation is identified with the dissipative collapse of the gas into...
1995-04-06
2009-09-25
[ "astro-ph" ]
C.S. Frenk, A.E. Evrard, S.D.M. White & FJ Summers
astro-ph/9504015
Spectrum of the relic neutrino background from past supernovae and cosmological models
It is greatly expected that the relic neutrino background from past supernovae is detected by Superkamiokande (SK) which is now under construction. We calculate the spectrum and the event rate at SK systematically by using the results of simulations of a supernova explosion and reasonable supernova rates. We also inves...
1995-04-06
2010-11-01
[ "astro-ph" ]
Tomonori Totani and Katsuhiko Sato (Tokyo Univ.)
astro-ph/9504019
Splitting of the Alfven surface in a relativistic pulsar wind
In a recent paper, Li and Melrose have claimed that the splitting - due to relativistic effects - of the Alfven surface in an axisymmetric pulsar wind does not occur. Here we refute this claim by showing that, unless the solution that describes the flow along each open magnetic field line passes through the pure Alfven...
1995-04-06
2015-06-24
[ "astro-ph" ]
H. Ardavan
astro-ph/9504014
A Warm-Plus-Hot Dark Matter Universe
We investigate a new hybrid-model universe containing two types of dark matter, one ``warm'' and the other ``hot''. The hot component is an ordinary light neutrino with mass $\sim 25h^2$~eV while the warm component is a sterile neutrino with mass $\sim 700h^2$~eV. The two types of dark matter arise entirely within the ...
1995-04-05
2009-10-28
[ "astro-ph", "hep-ph" ]
R.A. Malaney, G.D. Starkman, L. Widrow
astro-ph/9504011
Interstellar matter in Shapley-Ames elliptical galaxies. IV. A diffusely distributed component of dust and its effect on colour gradients
The presence of dust in elliptical galaxies has recently been shown to be quite common. Deep optical multi-colour CCD imaging has revealed the presence of dust lanes and patches, and the technique of co-adding IRAS survey scans has led to many detections of elliptical galaxies. The optical and far-infrared surveys repo...
1995-04-05
2008-11-26
[ "astro-ph" ]
Paul Goudfrooij (ESO Garching) and Teije de Jong (Laboratory for Space Research, Groningen)
astro-ph/9504012
Stochastic aggregation model for the multifractal distribution of matter
Two main features of the observable distribution of visible matter are the space correlations of galaxy positions and the mass function of galaxies. As discussed in Pietronero and Sylos Labini on this issue ([1], see also [2],[3]), the concept of multifractal (MF) distribution (including the masses) naturally unifies t...
1995-04-05
2016-08-30
[ "astro-ph" ]
F. Sylos Labini and L. Pietronero
astro-ph/9504004
Stable and Unstable Accretion Flows with Angular Momentum near a Point Mass
The properties of axisymmetric accretion flows of cold adiabatic gas with zero total energy in the vicinity of a Newtonian point mass are characterized by a single dimensionless parameter, the thickness of incoming flow. In the limit of thin accretion flows with vanishing thickness, we show that the governing equations...
1995-04-05
2009-10-28
[ "astro-ph" ]
Dongsu Ryu, Garry L. Brown, Jeremiah P. Ostriker, and Abraham Loeb
astro-ph/9504013
Cosmological Principle and the debate about Large Scale Structures distribution
The basic hypothesis of a post-Copernican Cosmological theory is that {\em all the points} of the Universe have to be essentially equivalent: this hypothesis is required in order to avoid any privileged {\em observer}. This assumption has been implemented by Einstein in the so-called Cosmological Principles (CP): {\em ...
1995-04-05
2009-10-28
[ "astro-ph" ]
L.Pietronero and F. Sylos Labini
astro-ph/9504005
A Study of the Large--Scale Distribution of Galaxies in the South Galactic Pole Region: I. The Data
We present the data from an extensive, moderately deep (b_J = 19.5) spectroscopic survey of $\sim 600$ galaxies within four regions of sky located near the South Galactic Pole. About 75% of the measured galaxies are in a 3deg x 1.5deg region dominated by the rich cluster Klemola 44 (Abell 4038). The other three smaller...
1995-04-04
2015-06-24
[ "astro-ph" ]
S. Ettori, L. Guzzo, M. Tarenghi
astro-ph/9504010
Do Gamma-Ray Burst Sources Repeat?
The demonstration of repeated gamma-ray bursts from an individual source would severely constrain burst source models. Recent reports (Quashnock and Lamb 1993; Wang and Lingenfelter 1993) of evidence for repetition in the first BATSE burst catalog have generated renewed interest in this issue. Here, we analyze the angu...
1995-04-04
2009-10-28
[ "astro-ph" ]
Charles A. Meegan (NASA/MSFC), Dieter H. Hartmann (Clemson), J. J. Brainerd (UAH), Michael S. Briggs (UAH), William S. Paciesas (UAH), Geoffrey Pendleton (UAH), Chryssa Kouveliotou (USRA), Gerald Fishman (NASA/MSFC), George Blumenthal (UCSC), Martin Brock (NASA/MSFC)
astro-ph/9504008
The Distribution of Mass and Gas in the Center of Clusters of Galaxies Implied by X-Ray and Lensing Observations
Observations of gravitational lensing indicate that the mass distribution in clusters of galaxies (where most of the mass is dark matter) is highly peaked towards the center, while X-ray observations imply that the gas is more extended. The additional fact that the gas is cooling in the center has often led one to expe...
1995-04-04
2009-10-28
[ "astro-ph" ]
Eli Waxman and Jordi Miralda-Escud\'e (Institute for Advanced Study)
astro-ph/9504006
Abundances in the Lyman--alpha clouds
We have re--examined the chemical composition of \lya clouds using the composite--cloud technique, in which each \lya line in a spectrum is shifted to its rest frame wavelength and all rest frame spectra are co--added to form an `averaged' \lya cloud spectrum. We illustrate how various estimates of the spectrum and red...
1995-04-04
2007-05-23
[ "astro-ph" ]
Sandra Savaglio & John Webb
astro-ph/9504007
EVOLUTION OF IR-SELECTED GALAXIES IN Z~0.4 CLUSTERS
Wide-field optical and near--IR ($JHK$) imaging is presented for two rich galaxy clusters: Abell~370 at $z=0.374$ and Abell~851 (Cl0939+47) at $z=0.407$. Galaxy catalogs selected from the near--IR images are 90\% complete to approximately 1.5 mag below $K^\ast$ resulting in samples with $\sim$100 probable member galaxi...
1995-04-04
2009-10-28
[ "astro-ph" ]
S.A. Stanford, P.R.M. Eisenhardt, and Mark Dickinson
astro-ph/9504009
Active vase mirrors warped by Zernike polynomials for Correcting off-axis aberrations of fixed primary mirrors. Part 2 - Optical testing and performance evaluation
We investigate the aspherization of an active mirror for correcting third and fifth-order aberrations. We use a stainless steel AISI 420 mirror with a controlled pressure load, two series of 12-punctual radial positions of force application distributed symmetrically in two concentric rings around the mirror. We obtain ...
1995-04-04
2019-08-15
[ "astro-ph" ]
G. Moretto, G. R. LemaitreT. Bactivelane, M. Wang, M. Ferrari, S. Mazzanti, B. Di Biagio and E.F. Borra
astro-ph/9503125
Cosmological Dynamics
This is a set of lecture notes basd on the lectures on cosmological dynamics given by E. Bertschinger at Les Houches in August 1993. The contents include elementary mechanics in cosmology, Eulerian and Lagrangian fluid dynamics, hot dark matter, and relativistic cosmological perturbation theory. To typeset the notes on...
1995-04-03
2007-05-23
[ "astro-ph" ]
Edmund Bertschinger
astro-ph/9504001
REMOVING DEGENERACY OF MICROLENSING LIGHT CURVES THROUGH NARROW-BAND PHOTOMETRY OF GIANTS
The standard light curve of a microlensing event provides only two constraints on the six unknown parameters of the lens. We show that narrow-band photometry during a microlensing event of a giant star can in addition determine the angular radius of the Einstein ring and the proper motion of the lens. This possibility ...
1995-04-03
2009-10-28
[ "astro-ph" ]
Abraham Loeb and Dimitar Sasselov (Harvard Univ.)
astro-ph/9503124
A Study of the Stability Properties of SPH
When using a formulation of Smooth Particle Hydrodynamics (SPH) which conserves momentum exactly the motion of the particles is observed to be unstable to negative stress. It is also found that under normal circumstances a lattice of SPH particles is potentially unstable to transverse waves. This document is a summary ...
1995-04-03
2007-05-23
[ "astro-ph" ]
Joseph Peter Morris (Monash University, Melbourne)
astro-ph/9504003
The Cosmological Constant is Back
A diverse set of observations now compellingly suggest that Universe possesses a nonzero cosmological constant. In the context of quantum-field theory a cosmological constant corresponds to the energy density of the vacuum, and the wanted value for the cosmological constant corresponds to a very tiny vacuum energy dens...
1995-04-03
2014-10-13
[ "astro-ph", "hep-ph" ]
Lawrence M. Krauss and Michael S. Turner
astro-ph/9504002
COOLING FLOW MODELS OF THE X--RAY EMISSION AND TEMPERATURE PROFILES FOR A SAMPLE OF ELLIPTICAL GALAXIES
A simple spherically-symmetric, steady-state, cooling-flow description with gas loss (following Sarazin \& Ashe 1989), within galaxy models constrained by radially extended stellar dynamical data, is shown to provide generally reasonable fits to the existing data on X-ray emission profiles and temperatures for a set of...
1995-04-03
2009-10-28
[ "astro-ph" ]
Giuseppe Bertin and Thomas Toniazzo
astro-ph/9503123
Two X-ray Sources in 30 Doradus: Wolf-Rayet + Black Hole Binaries?
I report the detection of two X-ray sources of luminosities $\sim 10^{36} {\rm~ergs~s^{-1}}$ in the central region of 30 Doradus. These two sources appear point-like in images taken with the {\sl ROSAT} HRI. One of the sources is most likely associated with a close spectroscopic binary R140a2 (WN6) with an orbital peri...
1995-04-02
2009-10-28
[ "astro-ph" ]
Q. Daniel Wang (Northwestern University)
astro-ph/9503122
Numerical simulation of large-scale magnetic-field evolution in spiral galaxies
The evolution of large-scale magnetic fields in disk galaxies is investigated numerically. The gasdynamical simulations in a disk perturbed by spiral or bar potential are incorporated into the kinematic calculations of induction equations to elucidate the effects of non-axisymmetric disk structure on magnetic fields. T...
1995-04-02
2007-05-23
[ "astro-ph" ]
K. Otmianowska-Mazur, M. Chiba
astro-ph/9503119
Measurement of the Mass Profile of Abell 1689
In this letter we present calibrated mass and light profiles of the rich cluster of galaxies Abell 1689 out to 1 $h^{-1}$ Mpc from the center. The high surface density of faint blue galaxies at high redshift, selected by their low surface brightness, are unique tools for mapping the projected mass distribution of foreg...
1995-04-01
2016-08-30
[ "astro-ph" ]
J. A. Tyson and P. Fischer
astro-ph/9503120
26Al and 60Fe From Supernova Explosions
Using recently calculated yields for Type II supernovae, along with models for chemical evolution and the distribution of mass in the interstellar medium, the current abundances and spatial distributions of two key gamma-ray radioactivities, $^{26}$Al and $^{60}$Fe, are determined. The estimated steady state production...
1995-04-01
2009-10-28
[ "astro-ph" ]
F.X.Timmes, S.E.Woosley, D.H.Hartmann, R.D.Hoffman, T.A.Weaver, and F.Matteucci
astro-ph/9503118
OLD ISOLATED ACCRETING NEUTRON STARS: CONTRIBUTION TO THE SOFT X--RAY BACKGROUND IN THE 0.5--2 KEV BAND
The issue of the observability of Old Isolated Neutron Stars (ONSs) accreting from the interstellar gas, is reconsidered using the spectra presented in Zampieri {\it et al.\/} (1995). In particular, we focus our attention on the overall soft X--ray emission of ONSs, which may provide a substantial contribution to the X...
1995-03-31
2009-10-28
[ "astro-ph" ]
Silvia Zane, Roberto Turolla, Luca Zampieri, Monica Colpi, Aldo Treves
astro-ph/9503121
A New Statistical Indicator to Study Nonlinear Gravitational Clustering and Structure Formation
In an expanding universe, velocity field and gravitational force field are proportional to each other in the linear regime. Neither of these quantities evolve in time and these can be scaled suitably so that the constant of proportionality is unity and velocity and force field are equal. The Zeldovich approximation ext...
1995-03-31
2009-10-28
[ "astro-ph" ]
J.S.Bagla and T.Padmanabhan
astro-ph/9503117
A Multiwavelength Picture of the AFGL 5142 Star-forming Region
We present molecular line, H2O maser, radio continuum and near infrared maps of the bipolar outflow source AFGL5142. The high resolution of our molecular CO observations enables us to define the morphology of the large-scale bipolar outflow into a two lobe structure extending for 2' on each side of the center. In the p...
1995-03-31
2007-05-23
[ "astro-ph" ]
Todd R. Hunter (CIT), Leonardo Testi (Arcetri), Greg B. Taylor (CIT), Marcello Felli (Arcetri), Gianni Tofani (Arcetri) and Thomas G. Phillips (CIT)
astro-ph/9503114
What is the Small-Scale Velocity Dispersion of Galaxy Pairs?
We present some new results from an ongoing investigation of the anisotropy of the two--point correlation function for optically selected galaxies. We have estimated xi(r_p,pi) from the Perseus-Pisces redshift survey, which is now virtually 100\% complete for all morphological types to m_B = 15.5. We detect strong dist...
1995-03-30
2007-05-23
[ "astro-ph" ]
L. Guzzo, K.B. Fisher, M.S. Strauss, R. Giovanelli, M.P. Haynes
astro-ph/9503116
A faint galaxy redshift survey to B=24
Using the multislit LDSS-2 spectrograph on the {\it William Herschel Telescope} we have completed a redshift survey in the magnitude range $22.5<B< 24$ which has produced 73 redshifts representing a 73\% complete sample uniformly-selected from four deep fields at high Galactic latitude. The survey extends out to $z>1$ ...
1995-03-30
2015-06-24
[ "astro-ph" ]
K. Glazebrook, R. Ellis, M. Colless, T. Broadhurst, J. Allington-Smith, N. Tanvir
astro-ph/9503115
Contribution to the Three--Point Function of the Cosmic Microwave Background from the Rees--Sciama Effect
We compute the contribution to the three--point temperature correlation function of the Cosmic Microwave Background coming from the non--linear evolution of Gaussian initial perturbations, as described by the Rees--Sciama (or integrated Sachs--Wolfe) effect. By expressing the collapsed three--point function in terms of...
1995-03-30
2011-05-10
[ "astro-ph" ]
Silvia Mollerach, Alejandro Gangui, Francesco Lucchin, and Sabino Matarrese
astro-ph/9503111
COSMOLOGY WITH CLUSTERS OF GALAXIES
Rich clusters of galaxies, the largest virialized systems known, provide a powerful tool for the study of cosmology. Some of the fundamental questions that can be addressed with clusters of galaxies include: how did galaxies and large-scale structure form and evolve? What is the amount, composition and distribution of ...
1995-03-29
2007-05-23
[ "astro-ph" ]
Neta A. Bahcall (Princeton University Observatory)
astro-ph/9503109
Evidence for Steep Luminosity Functions in Clusters of Galaxies
Luminosity Functions have been obtained for very faint dwarf galaxies in the cores of four rich clusters of galaxies (Abell 2052, 2107, 2199 and 2666). It is found that the luminosity function of dwarf galaxies rises very steeply in these clusters, with a power-law slope of \alpha -2.2 (down to absolute limiting magnit...
1995-03-29
2009-10-28
[ "astro-ph" ]
R. De Propris, C. J. Pritchet, W. E. Harris, R. D. McClure
astro-ph/9503112
CLUSTERING AND LARGE SCALE STRUCTURE WITH THE SDSS
The Sloan Digital Sky Survey (SDSS) will provide a complete imaging and spectroscopic survey of the high-latitude northern sky. The 2D survey will image the sky in five colors and will contain nearly 5 x 107 galaxies to g ~ 23m. The spectroscopic survey will obtain spectra of the brightest 106 galaxies, 105 quasars, an...
1995-03-29
2009-10-28
[ "astro-ph" ]
Neta A. Bahcall (Princeton University Observatory)
astro-ph/9503113
A STRINGENT CONSTRAINT ON ALTERNATIVES TO A MASSIVE BLACK HOLE AT THE CENTER OF NGC 4258
There is now dynamical evidence for massive dark objects at the center of several galaxies, but suggestions that these are supermassive black holes are based only on indirect astrophysical arguments. The recent unprecedented measurement of the rotation curve of maser emission sources at the center of NGC 4258, and the ...
1995-03-29
2009-10-28
[ "astro-ph" ]
Eyal Maoz
astro-ph/9503108
A NEW METHOD OF STUDYING GALAXY VELOCITY FIELD: FIRST RESULTS
It is shown that the average magnitude - redshift diagram for a magnitude-limited sample of galaxies can be effectively used for mapping galaxy velocity field. This new approach is quantitatively introduced and applied to the CfA, ESO/LV and ZCAT samples of galaxies. Strong arguments are presented for infall velocities...
1995-03-29
2016-06-08
[ "astro-ph" ]
Jacek Choloniewski
astro-ph/9503106
NEAR-SURFACE EFFECTS IN MODELLING OSCILLATIONS OF ETA BOO
Following the report of solar-like oscillations in the G0 V star eta Boo (Kjeldsen et al. 1995, AJ 109, 1313), a first attempt to model the observed frequencies was made by Christensen-Dalsgaard et al. (1995, ApJ Letters, in press). This attempt succeeded in reproducing the observed frequency separations, although ther...
1995-03-29
2007-05-23
[ "astro-ph" ]
J. Christensen-Dalsgaard, T.R. Bedding, G. Houdek, H. Kjeldsen, C. Rosenthal, R. Trampedach, M.J.P.F.G. Monteiro & A. Nordlund
astro-ph/9503110
RATING COSMOLOGICAL MODELS
I summarize the successes and failures of the most popular current cosmological models in accounting for the available observations. This evaluation, presented as the summary of the 11th Potsdam Workshop on Large-Scale Structure, was discussed by all the participants. I present the ratings given to each model based on ...
1995-03-29
2007-05-23
[ "astro-ph" ]
Neta A. Bahcall (Princeton University Observatory)
astro-ph/9503102
The Luminosity Function of the Coma Cluster Core for -25<M_R<-11
We determine the luminosity function (LF) of galaxies in the core of the Coma cluster for M_R<=-11.4 (assuming H_0=75 km/s/Mpc), a magnitude regime previously explored only in the Local Group. Objects are counted in a deep CCD image of Coma having RMS noise of 27.7 R mag~arcsec$^{-2}$. A correction for objects in the f...
1995-03-28
2009-10-28
[ "astro-ph" ]
G. M. Bernstein, R. C. Nichol, J. A. Tyson, M. P. Ulmer, and D. Wittman
astro-ph/9503101
The morphological identification of the rapidly evolving population of faint galaxies
The excess numbers of blue galaxies at faint magnitudes are a long-standing cosmological puzzle. We present new number-magnitude counts as a function of galactic morphology from the first deep fields of the Cycle 4 Hubble Space Telescope {\it Medium Deep Survey} project. From a sample of 301 galaxies we define counts f...
1995-03-28
2016-06-08
[ "astro-ph" ]
Karl Glazebrook, Richard Ellis, Basilio Santiago (Institute of Astronomy, Cambridge) and Richard Griffiths (Johns Hopkins University)
astro-ph/9503103
Deformation of Rapidly Rotating Compact Stars
We have developed a numerical code to study the deformation ($\varepsilon = (I_{zz}-I_{xx})/I_{zz}$, where $I_{ii}$ are the moments of inertia) of neutron stars in rapidly rotation in a fully general relativistic calculation. We have found that the deformation is larger, depending on the angular velocity, than is gener...
1995-03-28
2007-05-23
[ "astro-ph" ]
J.C.N. de Araujo, J.A. de Freitas Pacheco, M. Cattani and J.E. Horvath (IAG/USP)
astro-ph/9503105
Fireballs in Dense Stellar Regions as an explanation of Gamma Ray Bursts
We study a cosmological scenario for gamma ray bursts (GRBs) where relativistic flows interact with dense radiation fields. It is shown that this scenario is plausible in very dense stellar regions which are known to exist in collapsed cores of globular clusters or dense nuclei of galaxies. It yields a correct quantita...
1995-03-28
2015-06-24
[ "astro-ph" ]
Nir J. Shaviv and Arnon Dar
astro-ph/9503104
Lattice Stellar Dynamics
We describe a technique for solving the combined collisionless Boltzmann and Poisson equations in a discretised, or lattice, phase space. The time and the positions and velocities of `particles' take on integer values, and the forces are rounded to the nearest integer. The equations of motion are symplectic. In the lim...
1995-03-28
2015-06-24
[ "astro-ph" ]
D. Syer and S. Tremaine, (CITA)
astro-ph/9503107
Cooling flows, central galaxy--cluster alignments, X-ray absorption and dust
We present the analysis of pointed ROSAT PSPC observations of five of the most luminous, intermediate redshift ($0.1 < z < 0.15$) clusters of galaxies detected in the ROSAT All-Sky Survey. The PSPC data are combined with optical CCD images and spectra to examine the relationship between clusters and their central clust...
1995-03-28
2015-06-24
[ "astro-ph" ]
S.W. Allen, A.C. Fabian, A.C. Edge, H. Bohringer, D.A. White
astro-ph/9503097
The age of old Magelanic Cloud clusters. I: NGC 2257.
Deep CCD photometry down to V=24.5 is presented for the old Magellanic Globular cluster NGC 2257. The main result cna be summarized as follows: i) the RGB Bump has been detected at V=18.7+-0.1, and is compatible with determination of this feature in GGCs; ii) NGC 2257 seems to be 2-3 Gyrs younger than a typical GGC; ii...
1995-03-27
2015-06-24
[ "astro-ph" ]
V.Testa, F.R.Ferraro, E. Brocato, V. Castellani
astro-ph/9503098
EROS: Short period Cepheids in the bar of the LMC.
We present Fourier analysis at 490\,nm for 87 Cepheid light curves in the bar of the Large Magellanic Cloud. The photometry has be obtained through the EROS project whose main purpose is the search for baryonic dark matter in the Galactic halo. The very high quality of the photometry and the good phase coverage enable ...
1995-03-27
2007-05-23
[ "astro-ph" ]
J.P. Beaulieu (EROS collaboration)
astro-ph/9503095
N-body Simulations of the Small Magellanic Cloud and the Magellanic Stream
An extensive set of N-body simulations has been carried out on the gravitational interaction of the Small Magellanic Cloud (SMC) with the Galaxy and the Large Magellanic Cloud (LMC). The SMC is assumed to have been a barred galaxy with a disc-to-halo mass ratio of unity before interaction and modelled by a large number...
1995-03-27
2015-06-24
[ "astro-ph" ]
L. Gardiner and M. Noguchi
astro-ph/9503096
Cluster lens reconstruction using only observed local data -- an improved finite-field inversion technique
Gravitational light deflection can distort the images of distant sources by its tidal effects. The population of faint blue galaxies is at sufficiently high redshift so that their images are distorted near foreground clusters, with giant luminous arcs being the most spectacular evidence for this effect. Much weaker dis...
1995-03-27
2007-05-23
[ "astro-ph" ]
Stella Seitz and Peter Schneider
astro-ph/9503099
Thick to Thin: The Evolutionary Connection Between PG 1159 Stars and the Thin Helium-Enveloped Pulsating White Dwarf GD 358
Seismological observations with the Whole Earth Telescope (WET) allow the determination of the subsurface compositional structure of white dwarf stars. The hot DO PG 1159 has a helium surface layer with a mass of 0.001 Msun, while the cooler DB white dwarf GD 358 has a much thinner surface helium layer of 10^-6 Msun. T...
1995-03-27
2009-10-08
[ "astro-ph" ]
Benjamin T. Dehner and Steven D. Kawaler
astro-ph/9503094
HELIUM PHOTODISINTEGRATION AND NUCLEOSYNTHESIS: IMPLICATIONS FOR TOPOLOGICAL DEFECTS, HIGH ENERGY COSMIC RAYS, AND MASSIVE BLACK HOLES
We consider the production of $^3$He and $^2$H by $^4$He photodisintegration initiated by non-thermal energy releases during early cosmic epochs. We find that this process cannot be the predominant source of primordial $^2$H since it would result in anomalously high $^3$He/D ratios in conflict with standard chemical ev...
1995-03-26
2008-11-26
[ "astro-ph" ]
G.Sigl, K.Jedamzik, D.N.Schramm, and V.S.Berezinsky
astro-ph/9503093
THE FORMATION OF LSB GALAXIES
The formation of low surface brightness galaxies is an unavoidable prediction of any hierarchical clustering scenario. In these models, low surface brightness galaxies form at late times from small initial overdensities, and make up most of the faint end of the galaxy luminosity function. Because there are tremendous o...
1995-03-26
2007-05-23
[ "astro-ph" ]
J. J. Dalcanton, D. N. Spergel, and F J Summers
astro-ph/9503092
Millisecond Pulsars: Detectable Sources of Continuous Gravitational Waves?
Laboratory searches for the detection of gravitational waves have focused on the detection of burst signals emitted during a supernova explosion, but have not resulted in any confirmed detections. An alternative approach has been to search for continuous wave (CW) gravitational radiation from the Crab pulsar. In this p...
1995-03-25
2010-11-01
[ "astro-ph", "gr-qc" ]
Kimberly C. B. New, G. Chanmugam, Warren W. Johnson, and Joel E. Tohline (Louisiana State University)
astro-ph/9503090
Cepheids in the Magellanic Clouds
In the past few years, the Magellanic Clouds have been the targets for several major variable star surveys. The results of these surveys are now becoming available and it is clear that a Renaissance in LMC and SMC variable star research will result. In this review, I will describe the results of such surveys and review...
1995-03-25
2007-05-23
[ "astro-ph" ]
D.L. Welch, C. Alcock, D.P. Bennett, K.H. Cook, R.A. Allsman, T.S. Axelrod, K.C. Freeman, B.A. Peterson, P.J. Quinn, A.W. Rodgers, K. Griest, S.L. Marshall, M.R. Pratt, C.W. Stubbs, and W. Sutherland (The MACHO Collaboration)
astro-ph/9503091
A possible correlation between EGRET Sources and an Air-Borne experiment
In 1989, an air-borne experiments (VEGA experiment) aiming at the detection of a few 10 GeV $\gamma$-ray were carried out. In these experiments, nine point-source candidates along the Galactic plane were reported. In these candidates, the five of five highest significance candidates positionally coincide with the EGRET...
1995-03-25
2007-05-23
[ "astro-ph" ]
Ryoji Enomoto
astro-ph/9503088
On the Destruction and Over-Merging of Dark Halos in Dissipationless N-body Simulations
N-body simulations that follow only a collisionless dark matter component have failed to produce galaxy halos or substructure within dense environments. We investigate the `over-merging' problem analytically and with numerical simulations, by calculating dissolution timescales of halos due to physical and artificial dy...
1995-03-24
2009-10-28
[ "astro-ph" ]
Ben Moore, Neal Katz and George Lake
astro-ph/9503087
The Brightness Distribution of Bursting Sources in Relativistic Cosmologies
We present analytical solutions for the integral distribution of arbitrary bursting or steady source counts as a function of peak photon count rate within Friedmann cosmological models. We discuss both the standard candle and truncated power-law luminosity function cases with a power-law density evolution. While the an...
1995-03-24
2009-10-28
[ "astro-ph", "gr-qc" ]
P. Meszaros and A. Meszaros
astro-ph/9503089
High Redshift Lyman Limit and Damped Lyman-Alpha Absorbers
We have obtained high signal:to:noise optical spectroscopy at 5\AA\ resolution of 27 quasars from the APM z$>$4 quasar survey. The spectra have been analyzed to create new samples of high redshift Lyman-limit and damped Lyman-$\alpha$ absorbers. These data have been combined with published data sets in a study of the r...
1995-03-24
2007-05-23
[ "astro-ph" ]
L.J. Storrie-Lombardi, R.G. McMahon, M.J. Irwin, C. Hazard
astro-ph/9503086
Elimination of resonant divergences from QED in super-strong magnetic fields
We study the resonant divergences that occur in quantum scattering cross-sections in the presence of a strong external magnetic field. We demonstrate that all such divergences may be eliminated by introducing radiative corrections to the leading-order scattering amplitudes. These corrections impose a choice of basis st...
1995-03-23
2009-10-28
[ "astro-ph" ]
Carlo Graziani, Alice K. Harding, and Ramin Sina
astro-ph/9503085
Are Unidentified EUV Sources the Closest Neutron Stars?
Unidentified extreme UV sources, detected in the {\it EUVE} and {\it ROSAT} WFC all-sky surveys, could be isolated old neutron stars, accreting material from the ISM. The closest neutron stars, that are located in the local ISM bubble of unusually low density, are faint and cool ($L \sim 10^{27} {\rm \ erg \ s^{-1}}$, ...
1995-03-23
2016-06-08
[ "astro-ph" ]
Amotz Shemi
astro-ph/9503083
WFPC2 aperture photometry and PSF modelling
Since the WFPC-2 undersamples the PSF, aperture photometry can produce results which are competetive with profile fitting in many situations. This article reports and investigation of aperture corrections using both real data and PSF models.
1995-03-22
2007-05-23
[ "astro-ph" ]
N.R. Tanvir, D.R.T. Robinson, T. von Hippel
astro-ph/9503082
Radio observations of the gamma-ray quasar 0528+134: Superluminal motion and an extreme scattering event
We report on multifrequency radio observations made with the Effelsberg 100-m telescope, the IRAM 30-m telescope and the Green Bank Interferometer between 1992 and 1994 of the $\gamma$-ray quasar 0528+134. We present a new VLBI based map of 0518+134 at 22 GHz with sub-mas angular resolution observed in November 1992, w...
1995-03-22
2007-05-23
[ "astro-ph" ]
M. Pohl, W. Reich, T. P. Krichbaum, K. Standke, S. Britzen, H. P. Reuter, P. Reich, R. Schlickeiser, R. L. Fiedler, E. B. Waltman, F. D. Ghigo, K. J. Johnston
astro-ph/9503084
Star formation in normal and barred cluster spirals
An objective prism H alpha survey has shown that there is a population of early type spiral galaxies in nearby clusters with strong central bursts of star formation which could be due to galaxy--galaxy tidal interactions. Such galaxies are rarely found in the field.
1995-03-22
2007-05-23
[ "astro-ph" ]
C. Moss, M. Whittle, J.E. Pesce, H. Navarro
astro-ph/9503081
Lithium Abundance of Halo Dwarfs Revised
Lithium abundances in a sample of halo dwarfs have been redetermined by using the new T$_{eff}$ derived by Fuhrmann et al (1994) from modelling of the Balmer lines. These T$_{eff}$ are reddening independent, homogeneous and of higher quality than those based on broad band photometry. Abundances have been derived by gen...
1995-03-21
2007-05-23
[ "astro-ph" ]
P. Molaro (Osservatorio Astronomico di Trieste), F. Primas (Dipartimento di Astronomia, Universita` degli Studi di Trieste) P. Bonifacio (Dipartimento di Astronomia, Universita` degli Studi di Trieste)
astro-ph/9503078
On the electrodynamics of a magnetized rotating accretor
We consider the current flow in an accreting rotating neutron star (X-ray pulsator) and propose that the active magnetosphere is limited by the Alfv\`en surface. Formulae for the luminosity and torque due to currents circulating in the neutron star are given, and astrophysical consequences for systems like Her X-1 and ...
1995-03-21
2015-06-24
[ "astro-ph" ]
Aldo Treves and Ewa Szuszkiewicz
astro-ph/9503077
Evolution Of Gravitational Potential In The Quasilinear And Nonlinear Regimes
We study the evolution of the power spectrum of gravitational potential during the nonlinear clustering in an $\Omega=1$ matter dominated phase. N-body simulations suggest that the potential does not evolve in time even in the quasilinear phase for an $n=-1$ power spectrum. For $n=-2$, the potential evolves in the quas...
1995-03-21
2007-05-23
[ "astro-ph" ]
J.S.Bagla and T.Padmanabhan
astro-ph/9503079
The Onset of the Cold HI Phase in Disks of Protogalaxies
We discuss a possible delay experienced by protogalaxies with low column density of gas in forming stars over large scales. After the hydrogen has recombined, as the external ionizing UV flux decreases and the metal abundance $Z$ increases, the HI, initially in the warm phase ($T\simgt 5000$ K), makes a transition to t...
1995-03-21
2009-10-28
[ "astro-ph" ]
Edvige Corbelli, Edwin E. Salpeter
astro-ph/9503080
Instabilities in Photoionized Interstellar Gas
We present a linear analysis of acoustic and thermo-reactive instabilities in a diffuse gas, photoionized and heated by a radiation field, cooled by collisional excitation of hydrogen and metal lines. The hydrogen recombination reaction has a stabilizing effect on the thermal mode found by Field (1965) since the conden...
1995-03-21
2009-10-28
[ "astro-ph" ]
Edvige Corbelli, Andrea Ferrara
astro-ph/9503075
On the Oxygen Abundance of Neutral Gas in I Zw 18
Whether the H II regions of dwarf emission-line galaxies are self-polluted by the nucleosynthetic products of massive stars remains an open question, despite recent claims to the contrary. We show that the finding by Kunth and collaborators that the neutral interstellar medium of I Zw 18 has a metallicity one order of ...
1995-03-20
2007-05-23
[ "astro-ph" ]
Max Pettini (RGO, Cambridge) and Keith Lipman (IoA, Cambridge)
astro-ph/9503076
Massive stars as important contributors to two micron light
Near infrared light at 2 micrometers is relatively insensitive to the presence of hot young stars and dust in galaxies, and there has been recent interest in using it as a mass tracer in spiral galaxies. I present evidence that young, cool supergiant stars, whose presence is indicated by strong CO absorption in a 2.36 ...
1995-03-20
2007-05-23
[ "astro-ph" ]
James E. Rhoads (Princeton University)
astro-ph/9503074
FACTS AND IDEAS IN MODERN COSMOLOGY
A review of the principles of observational testing of cosmological theories is given with a special emphasis on the distinction between observational facts and theoretical hypotheses. A classification of modern cosmological theories and possible observational tests for these theories is presented. The main rival cosmo...
1995-03-20
2009-10-28
[ "astro-ph" ]
Yu. V. Baryshev F. Sylos Labini M. Montuori L. Pietronero
astro-ph/9503071
The Large Magellanic Cloud cluster NGC 2214
Johnson {\it BV} CCD observations have been made of the young Large Magellanic Cloud cluster NGC~2214 and a nearby field using the Anglo-Australian Telescope. It has been suggested in the literature that this elliptical cluster is actually two clusters in the process of merging. No evidence is found from profile fittin...
1995-03-17
2015-06-24
[ "astro-ph" ]
Timothy Banks, R.J. Dodd and D.J.Sullivan
astro-ph/9503072
THE LOCAL GALAXY DENSITY AND THE BULGE-TO-DISK RATIO OF DISK GALAXIES
Relying on samples of disk galaxies for which a detailed photometric bulge/disk decomposition has been provided in the literature, we examine the dependence of the bulge-to-disk luminosity ratio (B/D) on the blue absolute luminosity and on the environmental density. In our statistical analysis of various B/D data sets ...
1995-03-17
2016-08-30
[ "astro-ph" ]
Giuliano Giuricin, Fusun Limboz Tektunali, Pierluigi Monaco, Fabio Mardirossian, Marino Mezzetti
astro-ph/9503073
MEASURING GALAXY MASSES USING GALAXY-GALAXY GRAVITATIONAL LENSING
We report a significant detection of weak, tangential distortion of the images of cosmologically distant, faint galaxies due to gravitational lensing by foreground galaxies. A mean image polarisation of $<p>=0.011\pm 0.006$ is measured for 3202 pairs of source galaxies with magnitudes $23< r \le 24$ and lens galaxies w...
1995-03-17
2016-08-30
[ "astro-ph" ]
Tereasa Brainerd, Roger Blandford, and Ian Smail
astro-ph/9503068
WHEN DO SUPERNOVA NEUTRINOS OF DIFFERENT FLAVORS HAVE SIMILAR LUMINOSITIES BUT DIFFERENT SPECTRA ?
Muon and tau neutrinos ($\nu_x$) interact with protoneutron star matter only via neutral currents and exchange energy with the stellar gas predominantly by neutrino-electron scattering and neutrino-pair processes. In contrast, electron neutrinos and antineutrinos ($\nu_e$ and $\bar\nu_e$) are frequently absorbed and pr...
1995-03-16
2016-08-30
[ "astro-ph", "hep-ph" ]
H.-Thomas Janka (Department of Astronomy and Astrophysics, University of Chicago)
astro-ph/9503069
Protostellar Jets: The Best Laboratories for Investigating Astrophysical Jets
Highly collimated supersonic jets are observed to emerge from a wide variety of astrophysical objects, ranging from Active Nuclei of Galaxies (AGN's) to Young Stellar Objects (YSOs) within our own Galaxy. Despite their different physical scales (in size, velocity, and amount of energy transported), they have strong mor...
1995-03-16
2015-06-24
[ "astro-ph" ]
Elisabete M. de Gouveia Dal Pino
astro-ph/9503067
Multi-Band Images of the Barred Galaxy NGC 1097
We present $B,V,R,J,H,K$ broad--band images of the barred galaxy NGC 1097. The optical and infrared colors maps trace the location of the major dust features. The dust lanes are relatively free of star formation and have low opacity. The depth of the dust lanes decreases as a function of wavelength so that they are dee...
1995-03-16
2009-10-28
[ "astro-ph" ]
A. C. Quillen, Jay. A. Frogel, L. E. Kuchinski, D. M. Terndrup
astro-ph/9503065
CCD Photometry of Distant Open Clusters. II -- NGC 6791
Three new photometric CCD-based datasets are presented for NGC~6791. They consist of deep UBV photometry (to $V_{lim} =24$, $B_{lim}=24$, $U_{lim} = 23$) of the central parts of the cluster and of selected fields around it, and of relatively shallower UBVI photometry for the whole cluster ($23' \times 23'$). The data h...
1995-03-16
2016-08-30
[ "astro-ph" ]
Janusz Kaluzny (Warsaw University) and Slavek Rucinski (University of Toronto)
astro-ph/9503064
A FIRST DETERMINATION OF THE SURFACE DENSITY OF GALAXY CLUSTERS AT VERY LOW X--RAY FLUXES
We present the first results of a serendipitous search for clusters of galaxies in deep ROSAT-PSPC pointed observations at high galactic latitude. The survey is being carried out using a Wavelet based Detection Algorithm which is not biased against extended, low surface brightness sources. A new flux--diameter limited ...
1995-03-16
2016-08-30
[ "astro-ph" ]
P. Rosati, R. Della Ceca, R. Burg, C. Norman, R. Giacconi
astro-ph/9503070
Empirical Constraints on Source Properties and Host Galaxies of Cosmological Gamma-Ray Bursts
We discuss several constraints on the properties of gamma-ray bursts (GRB) at cosmological distances. First we use the requirement that burst sources must be optically thin to pair production by photon-photon collisions in order to produce the observed nonthermal spectra. We derive probability distributions for the min...
1995-03-16
2009-10-28
[ "astro-ph" ]
Eric Woods and Abraham Loeb (Harvard Univ.)
astro-ph/9503066
The Dwarf Galaxy NGC 1705 -- A Highly Composite Stellar Population
We present visible and near-infrared images of the amorphous dwarf galaxy NGC 1705 in the $B$, $V$, $R$, $J$, $H$, and $K$ bands. Optical and near infrared colors in the galaxy are consistent with a composite population with colors similar to those of the bluest Sc nuclei. The contribution of young stars to the disk po...
1995-03-16
2016-08-15
[ "astro-ph" ]
A. C. Quillen, Solange V. Ram\'irez, Jay A. Frogel
astro-ph/9503061
EMBEDDED CLUSTERS IN GIANT EXTRAGALACTIC HII REGIONS II. EVOLUTIONARY POPULATION SYNTHESIS MODEL
A stellar population synthesis model, suitable for comparison with Giant Extragalactic HII Regions (GEHRs), is constructed incorporating the recent developments in modelling stellar evolution by Maeder and co-workers and stellar atmospheres by Kurucz. A number of quantities suitable for comparison with broad band data ...
1995-03-15
2016-08-30
[ "astro-ph" ]
Y.D. Mayya
astro-ph/9503059
M Giant Kinematics in Off-Axis Fields Between 150 and 300 Parsecs from the Galactic Center
We present radial velocities for approximately 40 stars in each of three optically obscured, off-axis, fields toward the Galactic bulge. Combined with the data presented by Blum et al. (1994), we now have mean radial velocities and radial velocity dispersions in four fields towards the Galactic bulge. These four fields...
1995-03-15
2016-08-30
[ "astro-ph" ]
Robert Blum, John Carr, Kris Sellgren, and Don Terndrup
astro-ph/9503060
Probing the Extraordinary Ends of Ordinary Stars: White Dwarf Seismology with the Whole Earth Telescope
During the final evolution of most stars, they shed their outer skin and expose their core of the hot ashes of nuclear burning. As these hot and very dense cores cool into white dwarf stars, they go through episodes of multiperiodic, nonradial g-mode pulsation. The tools of stellar seismology allow us to use the pulsat...
1995-03-15
2007-05-23
[ "astro-ph" ]
Steven D. Kawaler (Iowa State University)
astro-ph/9503062
Phase Transitions in the ISM --- A Source of Dissipative Behaviour
In this paper, by considering a simple fluid model, we investigate the role of phase transitions in the ISM on the galaxy scale gas dynamics. Cooling and heating timescales in the ISM are typically shorter than typical galactic rotation timescales, so the individual phases in the ISM can be assumed to be in temperature...
1995-03-15
2016-08-30
[ "astro-ph" ]
A. C. Quillen, C. B. Quillen
astro-ph/9503063
HST Observations of Giant Arcs: High Resolution Imaging Of Distant Field Galaxies.
We present HST imaging of eight spectroscopically-confirmed giant arcs, pairs and arclets. These objects have all been extensively studied from the ground and we demonstrate the unique advantages of HST imaging in the study of such features by a critical comparison of our data with the previous observations. In particu...
1995-03-15
2016-08-30
[ "astro-ph" ]
Ian Smail, Alan Dressler, Jean-Paul Kneib, Richard S. Ellis, Warrick J. Couch, Ray M. Sharples & Augustus Oemler Jr.
astro-ph/9503058
MORE ON SOLAR-LIKE OSCILLATIONS IN ETA BOO
We recently reported strong evidence for solar-like oscillations in the G0 IV star eta Boo (Kjeldsen et al. 1995, AJ 109, 1313). We measured small temperature fluctuations produced by oscillations through their effect on the equivalent widths of the Balmer lines. Here we address several issues that were raised at this ...
1995-03-14
2016-08-30
[ "astro-ph" ]
T.R. Bedding & H. Kjeldsen
astro-ph/9503057
CHEMICAL ABUNDANCES IN CLUSTERS OF GALAXIES
We study the origin of iron and alpha-elements (O, Mg, Si) in clusters of galaxies. In particular, we discuss the [O/Fe] ratio and the iron mass-to-luminosity ratio in the intracluster medium (ICM) and their link to the chemical and dynamical evolution of elliptical and lenticular galaxies. We adopt a detailed model of...
1995-03-14
2016-08-30
[ "astro-ph" ]
Francesca Matteucci and Brad K. Gibson
astro-ph/9503056
MOND and the seven dwarfs
Gerhard had recently analyzed the data on seven dwarf spheroidals, and concluded that these disagree with the predictions of MOND. We contend that this conclusion is anything but correct. With new data for three of the dwarfs the observations of all dwarfs are in compelling agreement with the predictions of MOND. Gerha...
1995-03-14
2016-08-30
[ "astro-ph" ]
Mordehai Milgrom (Weizmann Institute)
astro-ph/9503054
The COBE Normalization of CMB Anisotropies
With the advent of the COBE detection of fluctuations in the Cosmic Microwave Background radiation, the study of inhomogeneous cosmology has entered a new phase. It is now possible to accurately normalize fluctuations on the largest observable scales, in the linear regime. In this paper we present a model-independent m...
1995-03-14
2009-08-18
[ "astro-ph" ]
Martin White and Emory F. Bunn
astro-ph/9503052
Magnetic cycles and photometric variability of T Tauri stars
We consider the effects of stellar magnetic cycles on disc accretion in T Tauri stars where the inner region of the disc is disrupted by the stellar field. Using time-dependent disc models, we show that order unity variations in field strength can strongly modulate the accretion flow for cycle time-scales of years to d...
1995-03-13
2015-06-24
[ "astro-ph" ]
P.J. Armitage
astro-ph/9503050
Spectroscopy of Candidate Young Globular Clusters in NGC 1275
We present spectra of the brightest member of the population of compact blue objects discovered in the peculiar galaxy NGC 1275 by Holtzman et al. using Hubble Space Telescope images. These spectra show strong Balmer absorption lines like those observed in A-type stars, as expected if the object is a young globular clu...
1995-03-13
2009-10-28
[ "astro-ph" ]
Stephen E. Zepf, Dave Carter, Ray M. Sharples, and Keith M. Ashman
astro-ph/9503053
Tidal Excitation of Modes in Binary Systems with Applications to Binary Pulsars
We consider the tidal excitation of modes in a binary system of arbitrary eccentricity. For a circular orbit, the modes generally undergo forced oscillation with a period equal to the orbital period ($T$). For an eccentric orbit, the amplitude of each tidally excited mode can be written approximately as the sum of an o...
1995-03-13
2016-08-30
[ "astro-ph" ]
Pawan Kumar, Chi On Ao, and Eliot J. Quataert
astro-ph/9503051
ROTATION CURVES OF 967 SPIRAL GALAXIES: IMPLICATIONS FOR DARK MATTER.
We present the rotation curves of 967 spiral galaxies, obtained by deprojecting and folding the raw data published by Mathewson et al. (1992). Of these, 80 meet objective excellence criteria and are suitable for individual detailed mass modelling, while 820 are suitable for statistical studies. A preliminary analysis o...
1995-03-13
2016-08-30
[ "astro-ph" ]
Massimo Persic, Paolo Salucci, and Fulvio Stel
astro-ph/9503055
X-ray variability and 1mHz oscillations in TT ARI
Using the archival ROSAT observation of TT Ari, X-ray energy spectra in different orbital phases and power spectra of the intensity time series are presented. Spectral fits show that the source gets brighter during the observation. The orbital modulation of the X-ray counting rate and bremsstrahlung temperature suggest...
1995-03-13
2007-05-23
[ "astro-ph" ]
A.Bayka, A.Esendemir, U. Kiziloglu, M. A. Alpar, H. Ogelman, N.Ercan, G. Ikis
astro-ph/9503048
Late-Type Stars in M31. I.: A Photometric Study of AGB Stars and Metallicity Gradients.
We have imaged five 7\arcmin \x 7\arcmin\ fields in M31 spanning galactocentric radii from 4 to 32 kpc along the SW-major axis. The fields were observed through two broad-band (\V\ and \I) and two narrow-band (\CN\ and \TiO) filters. The broad-band data were used to construct \IvsVI\ color-magnitude diagrams (CMDs) and...
1995-03-11
2016-08-30
[ "astro-ph" ]
J.P. Brewer, H.B. Richer and D.R. Crabtree
astro-ph/9503049
A search for X-rays from five pulsars: PSR's 0740-28, 1737-30, 1822-09, 1915+13 and 1916+14
We report observations of PSR's 0740-28, 1737-30, 1822-09, 1915+13 and 1916+14 with ROSAT. In the 0.1-2.1 keV range upper limits to luminosity are derived for power law and blackbody spectra, using a range of $N_{H}$ estimates. The upper limit to the blackbody luminosity from PSR1822-09 turns out to be consistent with ...
1995-03-11
2007-05-23
[ "astro-ph" ]
M. A. Alpar, O. H. Guseinov, U. Kiziloglu, H. Ogelman