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astro-ph/9411035
The Anisotropy in the Cosmic Microwave Background At Degree Angular Scales
We detect anisotropy in the cosmic microwave background (CMB) at degree angular scales and confirm a previous detection reported by Wollack et al. (1993). The root-mean-squared amplitude of the fluctuations is $44^{+13}_{-7} \mu$K. This may be expressed as the square root of the angular power spectrum in a band of mult...
1994-11-08
2008-11-26
[ "astro-ph" ]
C. B. Netterfield, N. Jarosik, L. Page, D. Wilkinson, E. Wollack
astro-ph/9411030
Constraints on the Formation History of the Elliptical Galaxy NGC 3923 from the Colors of Its Globular Clusters
We present a study of the colors of globular clusters associated with the elliptical galaxy NGC 3923. Our final sample consists of Washington system C and T_1 photometry for 143 globular cluster candidates with an expected contamination of no more than 10%. We find that the color distribution of the NGC 3923 globular c...
1994-11-07
2009-10-22
[ "astro-ph" ]
Stephen E. Zepf, Keith M. Ashman, and Doug Geisler
astro-ph/9411023
Stellar Evolution and Mass Loss on the Asymptotic Giant Branch
Mass loss dominates the stellar evolution on the Asymptotic Giant Branch. The phase of highest mass-loss occurs during the last 1--10\% of the AGB and includes the so-called Miras and OH/IR stars. In this review I will discuss the characteristics and evolution of especially Miras, and discuss how they are linked to the...
1994-11-07
2009-10-22
[ "astro-ph" ]
Albert A. Zijlstra
astro-ph/9411028
Network Resources for Astronomers
The amount of data produced by large observational facilities and space missions has led to the archiving and on-line accessibility of much of this data, available to the entire astronomical community. This allows a much wider multi-frequency approach to astronomical research than previously possible. Here we provide a...
1994-11-07
2009-10-22
[ "astro-ph" ]
H.Andernach, R.J.Hanisch and F.Murtagh
astro-ph/9411025
On the galaxy luminosity function in the central regions of the Coma cluster
We have obtained new redshifts for 265 objects in the central 48~$\times$~25~arcmin$^2$ region of the Coma cluster. When supplemented with literature data, our redshift sample is 95~\% complete up to a magnitude b$_{26.5}$=18.0 (the magnitudes are taken from the photometric sample of Godwin et al. 1983). Using redshift...
1994-11-07
2007-05-23
[ "astro-ph" ]
A. Biviano, F. Durret, D. Gerbal, O. Le F\`evre, C. Lobo, A. Mazure, E. Slezak
astro-ph/9411031
A New Criterion for Bar-Forming Instability in Rapidly Rotating Gaseous and Stellar Systems. I. Axisymmetric Form
We analyze previous results on the stability of uniformly and differentially rotating, self-gravitating, gaseous and stellar, axisymmetric systems to derive a new stability criterion for the appearance of toroidal, m=2 Intermediate (I) and bar modes. In the process, we demonstrate that the bar modes in stellar systems ...
1994-11-07
2007-09-24
[ "astro-ph" ]
D.M. Christodoulou, I. Shlosman, J.E. Tohline
astro-ph/9411029
Recent Developments in Weak Lensing
Measurement of the gravitational distortion of images of distant galaxies is rapidly becoming established as a powerful probe of the dark mass distribution in clusters of galaxies. With the advent of large mosaics of CCD's these methods should provide a composite total mass profile for galaxy haloes and also measure th...
1994-11-07
2007-05-23
[ "astro-ph" ]
Nick Kaiser, Gordon Squires, Greg Fahlman, David Woods and Tom Broadhurst
astro-ph/9411027
How Complete is the Electronic Catalogue Archive at CDS in the Extragalactic Domain?
From the literature of 1987 to 1993 a representative sample was prepared of 500 papers with tabular information for >~50 supposedly extragalactic objects each. Regardless of their scientific value, but corrected for redundancy, these papers contain 842,000 entries. For the 374 papers with >100 entries each, the CDS FTP...
1994-11-07
2007-05-23
[ "astro-ph" ]
H. Andernach
astro-ph/9411026
Extragalactic Databases: Present and Future
Current extragalactic databases are reviewed, including object-oriented databases, astronomical catalogues and compilations, as well as image archives and object catalogues from large-scale surveys. One challenge of the future will be to maintain the accessibility of all published information on individual objects; the...
1994-11-07
2007-05-23
[ "astro-ph" ]
H. Andernach
astro-ph/9411024
Ages of Galactic Globular Clusters from the New Yale Isochrones
A new grid of theoretical isochrones based on the Yale stellar evolution code using the OPAL and Kurucz opacities has been constructed. The grid of isochrones spans a wide range of metallicities, helium abundances and masses. The construction of the isochrones is described and the isochrones are compared to galactic gl...
1994-11-07
2007-05-23
[ "astro-ph" ]
Brian Chaboyer, P. Demarque, D.B. Guenther, M.H. Pinsonneault & L.L. Pinsonneault
astro-ph/9411022
Local Nonlinear Approximations to the Growth of Cosmic Structures
Local nonlinear approximations to the growth of cosmic perturbations are developed, resulting in relations, at a given epoch, between the peculiar velocity and gravity fields and their gradients. Only the equation of motion is approximated, while mass conservation and the computation of the gravitational field are trea...
1994-11-06
2009-10-22
[ "astro-ph" ]
Paul J. Mancinelli and Amos Yahil
astro-ph/9411020
Cold + Hot Dark Matter Cosmology with $m(\nu_\mu) \approx m(\nu_\tau) \approx 2.4$ ev
Cold + Hot Dark Matter (CHDM) $\Omega=1$ cosmological models require a total neutrino mass $\sim 5$ eV. Because recent data support the $\nu_\mu \to \nu_\tau$ oscillation explanation of the cosmic ray $\nu_\mu$ deficit, which requires that $m(\nu_\mu) \approx m(\nu_\tau)$, this suggests that $m(\nu_\mu) \approx m(\nu_\...
1994-11-05
2009-10-22
[ "astro-ph", "hep-ph" ]
Joel R. Primack, Jon Holtzman, Anatoly Klypin, and David O. Caldwell Comments 8 pages, uuencoded compressed .ps file
astro-ph/9411021
The EINSTEIN On-Line Service
The Einstein On-Line Service (EOLS) is a simple menu-driven system which provides an intuitive method of querying over one hundred database catalogs. In addition, the EOLS contains over 30 CDROMs of images from the Einstein X-ray Observatory which are available for downloading. The EOLS provides all of our databases to...
1994-11-05
2007-05-23
[ "astro-ph" ]
D.E.Harris, C.S.Grant, and H.Andernach
astro-ph/9411019
Theory of Exploring the Dark Halo with Microlensing 1: Power--Law Models
The detection of microlensing has opened the way for the development of new methods in galactic astronomy. This series of papers investigates what microlensing can teach us about the structure and shape of the dark halo. In this paper we present formulas for the microlensing rate, optical depth and event duration distr...
1994-11-04
2009-10-22
[ "astro-ph", "hep-ph" ]
C.Alcock, R.A.Allsman, T.S.Axelrod, D.P. Bennett, K.H.Cook, N.W.Evans, K.C.Freeman, K. Griest, J.Jijina, M. Lehner, S.L.Marshall, S.Perlmutter, B.A.Peterson, M.R. Pratt, P.J.Quinn, A.W.Rodgers, C.W.Stubbs, and W. Sutherland (the MACHO collaboration)
astro-ph/9411018
A Scenario for a Baryonic Dark Halo
The recent observations of microlensing events in the LMC by the MACHO and EROS collaborations suggest that an important fraction of the galactic halo is in the form of Massive Halo Objects (MHO) of about 0.1 M_{\odot}. Here, we argue that the galactic halo is mainly baryonic and that besides MHO also H_2 molecular clo...
1994-11-04
2011-05-23
[ "astro-ph" ]
F. DePaolis, G. Ingrosso, Ph. Jetzer and M. Roncadelli
astro-ph/9411014
Higher Order Statistics from the Apm Galaxy Survey
We apply a new statistics, the factorial moment correlators, to density maps obtained from the APM survey. The resulting correlators are all proportional to the two point correlation function, substantially amplified, with an amplification nearly exponential with the total rank of the correlators. This confirms the val...
1994-11-03
2009-10-22
[ "astro-ph" ]
Istv\'an Szapudi, Gavin Dalton, George Efstathiou and Alexander Szalay
astro-ph/9411016
Solar-like oscillations in eta Boo
We have observed evidence for $p$-mode oscillations in the G0 IV star etaBoo (V = 2.68). This represents the first clear evidence of solar-like oscillations in a star other than the Sun. We used a new technique which measures fluctuations in the temperature of the star via their effect on the equivalent widths of the B...
1994-11-03
2009-10-22
[ "astro-ph" ]
Hans Kjeldsen, Timothy R. Bedding, Michael Viskum & Soeren Frandsen
astro-ph/9411013
Application of Gradient Expansion to Inflationary Universe
Using the long wave perturbation scheme(gradient expansion), the effect of inhomogeneity on the inflationary phase is investigated. We solved the perturbation equation of which source term comes from inhomogeneity of a scalar field and a seed metric. The result indicates that sub-horizon scale inhomogeneity strongly af...
1994-11-03
2009-10-22
[ "astro-ph", "gr-qc" ]
Yasusada Nambu and Atsushi Taruya
astro-ph/9411015
The radio spectrum of Sgr A*
We discuss the radio spectrum of Sgr A* \index{Sgr A*, radio spectrum} in the frequency range between $\approx 1\,{\rm GHz}$ and $\approx 1\,000\,{\rm GHz}$, show that it can be explained by optically thin synchrotron radiation \index{Sgr A*, synchrotron radiation, optically thin} of relativistic electrons, and point t...
1994-11-03
2007-05-23
[ "astro-ph" ]
Wolfgang J. Duschl and Harald Lesch
astro-ph/9411012
Competition of Supermassive Black Holes and Galactic Spheroids in the Destruction of Globular Clusters
The globular clusters that we observe in galaxies may be only a fraction of the initial population. Among the evolutionary influences on the population is the destruction of globular clusters by tidal forces as the cluster moves through the field of influence of a disk, a bulge, and/or a putative nuclear component (bla...
1994-11-03
2009-10-22
[ "astro-ph" ]
Jane C. Charlton and Pablo Laguna
astro-ph/9411017
The Cosmological Mass Distribution from Cayley Trees with Disorder
We present a new approach to the statistics of the cosmic density field and to the mass distribution of high-contrast structures, based on the formalism of Cayley trees. Our approach includes in one random process both fluctuations and interactions of the density perturbations. We connect tree-related quantities, like ...
1994-11-03
2009-10-22
[ "astro-ph" ]
A. Cavaliere, and N. Menci
astro-ph/9411010
Global field dynamics and cosmological tructure formation
We discuss gravitational effects of global scalar fields and, especially, of global topological defects. We first give an introduction to the dynamics of global fields and the formation of defects. Next we investigate the induced gravitational fields, first in a flat background and then in the expanding universe. In fl...
1994-11-02
2009-09-25
[ "astro-ph" ]
Ruth Durrer
astro-ph/9411011
The Evolution of C/O in Dwarf Galaxies from HST Fos Observations
We present FOS observations of O III] 1666 A and C III] 1909 A emission in H II regions in dwarf irregular galaxies to measure C/O abundance ratios in those galaxies. We observe a continuous increase in C/O with increasing O/H over the range -4.7 < log(O/H) < -3.6. One interpretation is that the most metal-poor galaxie...
1994-11-02
2009-10-22
[ "astro-ph" ]
D. R. Garnett, E. D. Skillman, R. J. Dufour, M. Peimbert, S. Torres-Peimbert, R. J. Terlevich, E.Terlevich, and G. A. Shields
astro-ph/9411005
A Method for Weak Lensing Observations
We develop and test a method for measuring the gravitational lensing induced distortion of faint background galaxies. We first describe how we locate the galaxies and measure a 2-component `polarisation' or ellipticity statistic $e_\alpha$ whose expectation value should be proportional to the gravitational shear $\gamm...
1994-11-01
2009-10-16
[ "astro-ph" ]
Nick Kaiser, Gordon Squires, and Tom Broadhurst
astro-ph/9411006
Discovery of a z=2.76 Dusty Radio Galaxy?
We report the discovery of a z=2.76 radio galaxy, MG1019+0535, with an unusual spectrum. Ly$\alpha$, which usually dominates the spectra of high redshift radio galaxies, is very weak and the strongest lines in the spectrum are CIV$\lambda$1549 and HeII$\lambda$1640. We speculate that dust is responsible for attenuating...
1994-11-01
2009-10-22
[ "astro-ph" ]
Arjun Dey (U.C.Berkeley), Hyron Spinrad (U.C.Berkeley), and Mark Dickinson (STScI)
astro-ph/9411007
Keck Observations of the Most Distant Galaxy: 8C1435+63 at z=4.25
We report on Keck observations and confirm the redshift of the most distant galaxy known: 8C1435+63 at z=4.25. The spectrum shows a strong Ly$\alpha$ line, a Ly$\alpha$ forest continuum break and a continuum break at $\lambda_{rest}=912$\AA. The Ly$\alpha$ emission is spatially extended and roughly aligned with the rad...
1994-11-01
2009-10-22
[ "astro-ph" ]
Hyron Spinrad, Arjun Dey and James R. Graham (U.C.Berkeley)
astro-ph/9411002
The Least Action Method, CDM and $\Omega$
Peebles has suggested an interesting method to trace back in time positions of galaxies called the least action method. This method applied on the Local Group galaxies seems to indicate that we live in an $\Omega\approx 0.1$ Universe. We have studied a CDM N-body simulation with $\Omega=0.2$ and $H=50 kms^{-1}/Mpc$ and...
1994-11-01
2009-10-22
[ "astro-ph" ]
A.M. Dunn and Raymond Laflamme
astro-ph/9411003
Galactic Chemical Evolution: Hydrogen Through Zinc
Using the output from a grid of 60 Type II supernova models (Woosley \& Weaver 1994) of varying mass (11 $\ltaprx$ M/M\sun $\ltaprx$ 40) and metallicity (0, 10$^{-4}$, 0.01, 0.1, and 1 Z\sol), the chemical evolution of 76 stable isotopes, from hydrogen to zinc, is calculated. The chemical evolution calculation employs ...
1994-11-01
2009-10-22
[ "astro-ph" ]
by F. X. Timmes, S. E. Woosley and Thomas A. Weaver
astro-ph/9411001
Cosmological Simulations Using Special Purpose Computers: Implementing P3M on Grape
An adaptation of the Particle-Particle/Particle-Mesh (P3M) code to the special purpose hardware GRAPE is presented. The short range force is calculated by a four chip GRAPE-3A board, while the rest of the calculation is performed on a Sun Sparc 10/51 workstation. The limited precision of the GRAPE hardware and algorith...
1994-11-01
2009-10-22
[ "astro-ph" ]
Philippe P. Brieu, FJ Summers, & Jeremiah P. Ostriker
astro-ph/9411008
Toward Understanding CMB Anisotropies and Their Implications
Working toward a model independent understanding of cosmic microwave background (CMB) anisotropies and their significance, we undertake a comprehensive and self-contained study of scalar perturbation theory. Initial conditions, evolution, thermal history, matter content, background dynamics, and geometry all play a rol...
1994-11-01
2009-09-25
[ "astro-ph" ]
Wayne Hu and Naoshi Sugiyama
astro-ph/9411009
Galaxy Formation from Spectroscopy of Extragalactic Globular Cluster Systems
I discuss how spectroscopy of extragalactic globular clusters provides a powerful probe of the formation history and mass distribution of galaxies. One critical area is spectroscopy of objects which have been identified as candidate young globular clusters through HST imaging of galaxy mergers. I discuss how such data ...
1994-11-01
2007-05-23
[ "astro-ph" ]
Stephen E. Zepf
astro-ph/9411004
Results from the Optical Gravitational Lensing Experiment (OGLE)
The analysis of the first three years of the OGLE data revealed 12 microlensing events of the Galactic bulge stars, with the characteristic time scales in the range $ 8.6 < t_0 < 80 $ days, where $ t_0 = R_E / V $. A complete sample of nine events gave the optical depth to gravitational microlensing larger than $(3.3 \...
1994-11-01
2007-05-23
[ "astro-ph" ]
B. Paczynski, K. Z. Stanek, A. Udalski, M. Szymanski, J. Kaluzny, M. Kubiak, M. Mateo, W. Krzeminski and G. W. Preston
astro-ph/9410097
Cosmic String Theory: The Current Status
This is a pedagogical introduction to the basics of the cosmic string theory and also a review of the recent progress made with respect to the macrophysical predictions of the theory. Topics covered include, string formation and evolution, large scale structure formation, generation of peculiar velocity flows, cosmic m...
1994-10-31
2009-09-25
[ "astro-ph", "hep-ph" ]
L. Perivolaropoulos (MIT, Center for Theoretical Physics)
astro-ph/9410098
Polarisation as a Tool for Gravitational Microlensing Surveys
Much interest has been generated recently by the ongoing MACHO, EROS and OGLE projects to identify gravitationally lensed stars from the Large Magellanic Cloud and Galactic bulge, and the positive identification of several events (Alcock et al, (1993), Aubourg et al, (1993) and Udalski et al, (1993)). The rate at which...
1994-10-31
2007-05-23
[ "astro-ph" ]
J.F.L. Simmons, J.P. Willis, A. Newsam
astro-ph/9410096
Influence of the Stellar Mass Function on the Evaporation Rate of Tidally Limited Postcollapse Globular Clusters
We study the rate of escape of stars (``evaporation'') from tidally-limited postcollapse globular clusters having a power-law distribution of stellar masses. We use a multi-mass Fokker-Planck code and assume a steady tidal field. Stellar-dynamical processes cause the inner parts of the cluster to expand, which in turn ...
1994-10-31
2007-05-23
[ "astro-ph" ]
Hyung Mok Lee and Jeremy Goodman
astro-ph/9410095
Galaxy Group Analysis - a Robust Discriminator between Cosmological Models: Cold+HOT Dark Matter and CDM Confront Cfa1
We present techniques for identifying and analyzing galaxy groups and show that they provide a powerful discriminator between cosmological models. We apply these to high-resolution PM N-body simulations of structure formation in CHDM (cold/hot/baryon fractions=.6/.3/.1, b=1.5 (COBE norm) and two CDM models; b=1.5 and b...
1994-10-30
2009-09-25
[ "astro-ph" ]
R. Nolthenius, A.A. Klypin, J.R. Primack
astro-ph/9410094
Neutrino Mixing Constraints and Supernova Nucleosynthesis
We reexamine the constraints on mixing between electron and muon or tau neutrinos from shock-reheating and r-process nucleosynthesis in supernovae. To this end neutrino flavor evolution is described by nonlinear equations following from a quantum kinetic approach. This takes into account neutrino forward scattering off...
1994-10-29
2009-10-22
[ "astro-ph", "hep-ph" ]
G.Sigl
astro-ph/9410093
On the Dynamical Origin of Bias in Clusters of Galaxies
We study the effect of the dynamical friction induced by the presence of substructure on the statistics of the collapse of density peaks. Applying the results of a former paper we show that within high density environments, like rich clusters of galaxies, the collapse of smaller peaks is strongly delayed until very lat...
1994-10-29
2009-10-22
[ "astro-ph" ]
S. Colafrancesco, V. Antonuccio-Delogu and A. Del Popolo
astro-ph/9410089
Lithium and the Nature of Brown Dwarf Candidates
This paper discusses the ability of Li to confirm the substellar nature of a brown dwarf candidate. Theoretical computations using different interior models agree that brown dwarfs with masses below $\sim$ 0.065 M$_{\odot}$ preserve a significant fraction of their initial Li content while for higher masses total Li dep...
1994-10-28
2007-05-23
[ "astro-ph" ]
R. Rebolo, A. Magazzu, E.L. Martin
astro-ph/9410091
Chaos, Regularity, and Noise in Self-Gravitating Systems
This paper summarises a number of new, potentially significant, results, obtained recently by the author and his collaborators, which impact on various issues related to the gravitational N-body problem, both Newtonianly and in the context of general relativity. Topics addressed include: (1) direct N-body simulations a...
1994-10-28
2008-02-03
[ "astro-ph", "chao-dyn", "gr-qc", "nlin.CD" ]
Henry E. Kandrup
astro-ph/9410092
Southern Binary Galaxies. I. a Sample of Isolated Pairs
A catalogue of binary galaxies with 621 pairs has been determined by applying a surface density enhancement procedure to {\it The Surface Photometry Catalogue of the ESO-Uppsala Galaxies}. The method does not require any redshift information. An additional restriction, based on objective criteria that take into account...
1994-10-28
2007-05-23
[ "astro-ph" ]
D.S.L. Soares, R.E. de Souza, R.R. de Carvalho, T.C. Couto da Silva
astro-ph/9410087
Vilnius CCD Photometry of Southern Clusters: Some Preliminary Results
The Vilnius Photometric system has been used with a CCD system only once before this study. Preliminary crowded field reductions of Vilnius CCD observations of the star clusters NGC~2004 and NGC~4755 (the $\kappa $ Crucis cluster) are presented, demonstrating the feasibility of using the filter set in this manner.
1994-10-28
2009-09-25
[ "astro-ph" ]
Timothy Banks, D.J. Sullivan, M.C. Forbes, & R.J. Dodd
astro-ph/9410090
Morhology and kinematics of eta Carinae
We present a high-resolution image of $\eta$~Car. Together with IR and visual observations of the central arcsecond, we use this to discuss the morphological structure of $\eta$~Car on the different length scales. We identify three different structural components: a bipolar outflow, an equatorial disk of streamers, and...
1994-10-28
2007-05-23
[ "astro-ph" ]
W.J.Duschl, K.-H.Hofmann, F.Rigaut, G.Weigelt
astro-ph/9410086
Anatomy of the Sagittarius A complex: IV. Sgr A* and the Central Cavity revisi- ted
We present submm images of Sgr A* and its surroundings obtained at 800, 600 and 450 $\mu$m with the JCMT and derive flux densities of Sgr A* at all three wave- lengths. Combined with upper limits by Gezari and associates at MIR wavelengths a time averaged radio spectrum is obtained which increases $\propto \nu^{1/3}$, ...
1994-10-27
2007-05-23
[ "astro-ph" ]
R.Zylka, P.G.Mezger, D.Ward-Thompson, W.J.Duschl, H.Lesch
astro-ph/9410084
Hot bubble and slow wind dynamics in PNe (Radiation-gasdynamics of PNe V)
This paper looks into various aspects brought to light by numerical work on the generalized interacting winds model for planetary nebulae. First, a detailed comparison between radiative and non-radiative models is made, showing that one's naive expectations of the effects of radiative heating and cooling are not always...
1994-10-27
2007-05-23
[ "astro-ph" ]
Garrelt Mellema and Adam Frank
astro-ph/9410088
A First Map of the CMB at 0.5Deg Resolution
We use a Maximum Entropy technique to reconstruct a map of the microwave sky near the star Gamma Ursae Minoris, based on data from flights 2, 3 and 4 of the Millimeter-wave Anisotropy eXperiment (MAX).
1994-10-27
2009-10-22
[ "astro-ph" ]
M.White and E.Bunn (CfPA)
astro-ph/9410083
Inflation as the Unique Causal Mechanism for Generating Density Perturbations on Scales Well Above the Hubble Radius
An examination is made of the widely held belief that inflation is the only possible causal mechanism capable of generating density perturbations on scales well in excess of the Hubble radius. A simple proof is given, which relies only on the assumption that our understanding of the universe from nucleosynthesis onward...
1994-10-27
2010-01-06
[ "astro-ph" ]
Andrew R Liddle
astro-ph/9410082
Young LMC star clusters as a test for stellar evolutionary models:
We compare the observed colour-magnitude diagrams (CMD) and the main sequence luminosity functions (LFs) of four Large Magellanic Cloud (LMC) star clusters namely, NGC 1711, NGC 2004, NGC 2164 and NGC 2214 with the synthetic ones derived from the stellar evolutionary models. Four different types of stellar evolutionary...
1994-10-27
2007-05-23
[ "astro-ph" ]
Annapurni Subramaniam, Ram Sagar
astro-ph/9410085
Hydrodynamic Evolution of Coalescing Compact Binaries
In addition to their possible relevance to gamma-ray bursts, coalescing binary neutron stars have long been recognized as important sources of gravitational radiation that should become detectable with the new generation of laser interferometers such as LIGO. Hydrodynamics plays an essential role near the end of the co...
1994-10-27
2007-05-23
[ "astro-ph" ]
F. A. Rasio and S. L. Shapiro
astro-ph/9410081
Analysis of Small and Medium-Scale Cosmic Microwave Background Experiments
Anisotropies in the temperature of the cosmic microwave background have been detected on a range of scales by several different experiments. These anisotropies reflect the primordial spectrum of metric perturbations in the early universe. In principle, the largest barrier to a clean interpretation of the experimental r...
1994-10-26
2009-10-22
[ "astro-ph" ]
Scott Dodelson (Fermilab) and Arthur Kosowsky (University of Chicago and CFA)
astro-ph/9410079
Momentum transfer by an internal source of ionizing radiation - an important feedback process during galaxy formation ?!
The role of momentum transfer (``radiation pressure'') due to an internal source of ionizing radiation for the formation of baryonic structures is investigated. Fully-ionized self-gravitating gaseous objects can be radiation-pressure supported on a characteristic length scale $D_{\rm rp} \sim 100 \pc - 3 \kpc$. On smal...
1994-10-25
2015-06-24
[ "astro-ph" ]
Martin G. Haehnelt
astro-ph/9410080
Wiener Reconstruction of The Large Scale Structure
The formalism of Wiener filtering is developed here for the purpose of reconstructing the large scale structure of the universe from noisy, sparse and incomplete data. The method is based on a linear minimum variance solution, given data and an assumed \prior model which specifies the covariance matrix of the field to ...
1994-10-25
2009-10-22
[ "astro-ph" ]
S. Zaroubi, Y. Hoffman, K.B. Fisher and O. Lahav
astro-ph/9410075
NGC 4526 gas, High Velocity Clouds, and Galactic Halo gas: the Interstellar Medium towards SN 1994D
We present spectroscopic observations of supernova 1994D in NGC 4526, an S0$_3$ galaxy in the Virgo cluster 15 Mpc distant. The datasets consist of the interstellar Ca\II\ and Na\I\ lines towards the supernova at high spectral resolution (FWHM 6 \kms), \halpha\ and [N\,II] observations at lower resolution (FWHM 33 \kms...
1994-10-24
2007-05-23
[ "astro-ph" ]
D. L. King (RGO), G. Vladilo (Trieste), K. Lipman (IoA), K. S. de Boer (Bonn), M Centurion (IAC), P. Moritz (Bonn), N. A. Walton (RGO)
astro-ph/9410078
A deep ROSAT survey - IV. The evolution of X-ray-selected QSOs
We report on a new estimate of the QSO X-ray luminosity function and its evolution with redshift based on a sample of 107 QSOs detected at faint X-ray fluxes, $S{\rm(0.5-2\,keV)}>4\times10^{-15}\,$\ergcms , with the {\it ROSAT} X-ray satellite. For $q_0=0.5$, the X-ray evolution of QSOs in this sample is consistent wit...
1994-10-24
2015-06-24
[ "astro-ph" ]
B.J.Boyle (IoA, Cambridge), T.Shanks (Durham), I.Georgantopoulos (Leicester) G.C.Stewart (Leicester) and R.E.Griffiths (JHU)
astro-ph/9410076
Arc Statistics with Realistic Cluster Potentials. III. a Systematic Effect on Cluster Mass Estimates
It is shown in this paper that deviations of galaxy cluster lenses from spherical symmetry can render mass estimates for galaxy clusters based on the formation of large arcs systematically to high. Numerical models show that the mass needed for producing large arcs in clusters can be notably smaller than expected from ...
1994-10-24
2011-05-23
[ "astro-ph" ]
Matthias Bartelmann
astro-ph/9410074
Interstellar Titanium in the Galactic Halo
We present observations of Ti~II~$\lambda 3384$ absorption towards 15 distant stars in the Galactic halo and the Magellanic Clouds. These new data extend existing surveys of the distribution of Ti$^+$ to larger distances from the plane of the Galaxy than sampled previously, allowing the scale height of titanium to be d...
1994-10-24
2009-10-22
[ "astro-ph" ]
Keith Lipman (IoA, Cambridge) and Max Pettini (RGO, Cambridge)
astro-ph/9410077
The Cambridge-Cambridge ROSAT Serendipity Survey - I. X-ray-luminous galaxies
We report on the first results obtained from a new optical identification programme of 123 faint X-ray sources with $S$(0.5--2$\,{\rm keV)}>2\times 10^{-14}\,$erg$\,$s$^{-1}\,$cm$^{-2}\,$ serendipitously detected in {\it ROSAT} PSPC pointed observations. We have spectroscopically identified the optical counterparts to ...
1994-10-24
2015-06-24
[ "astro-ph" ]
B.J.Boyle (RGO, Cambridge), R.G.Mcmahon (IoA, Cambridge), B.J.Wilkes and M.Elvis (CfA)
astro-ph/9410073
The Search for Black Holes in X-Ray Binaries: An Update
This paper reviews some of the recent observational results on stellar mass black hole candidates. Over the last decade, much of the progress in this field has been achieved through the study of transient X--ray binary sources which shine only sporadically in the X--ray sky and undergo much larger luminosity variations...
1994-10-23
2009-09-25
[ "astro-ph" ]
L. Stella, G.L. Israel, S. Mereghetti and D. Ricci
astro-ph/9410072
Nature of Field Galaxies in the (z<0.3) Universe from the CFRS Survey
We present the first detailed spectroscopic study of field galaxies up to z=0.3 from the I-magnitude limited CFRS sample. In this complete sample, we find that about half of the objects are blue emission-line galaxies. Using line ratio diagram and photoionization models, we show that in roughly half of these emission-l...
1994-10-21
2007-05-23
[ "astro-ph" ]
L. Tresse, C. Rola, F. Hammer, G. Stasinska
astro-ph/9410066
The Power Spectrum of Galaxies in the Nearby Universe
We compute the power spectrum of galaxy density fluctuations in a recently completed redshift survey of optically-selected galaxies in the southern hemisphere (SSRS2). The amplitude and shape of the SSRS2 power spectrum are consistent with results of the Center for Astrophysics redshift survey of the northern hemispher...
1994-10-20
2009-10-22
[ "astro-ph" ]
L. N. da Costa, M. S. Vogeley, M. J. Geller, J. P. Huchra, and C. Park
astro-ph/9410071
Short times characterisations of stochasticity in nonintegrable galactic potentials
This paper proposes an alternative characterisation of the degree of stochasticity exhibited by orbits in a fixed galactic potential. This differs from earlier work involving Liapounov exponents by focusing on the statistical properties of ensembles of trajectories, rather than individual orbits, and by restricting att...
1994-10-20
2011-05-23
[ "astro-ph", "chao-dyn", "nlin.CD" ]
Henry E. Kandrup and M. Elaine Mahon
astro-ph/9410065
MeV Tau Neutrino: Astrophysical and Cosmological Constraints and Mischief
Terrestrial and ``Heavenly'' experiments severely constrain the mass and lifetime of an MeV tau neutrino. Irrespective of decay mode, for $\tau_\nu \ga 300\sec$ the mass of the tau neutrino must be either approximately $30\MeV$ or less than $0.4\MeV$ (Majorana), $15\keV$ (Dirac). If the dominant decay mode includes ele...
1994-10-20
2009-10-22
[ "astro-ph" ]
Geza Gyuk and Michael S. Turner
astro-ph/9410069
In Search of a Source for the 320 Eev Fly's Eye Cosmic Ray
The 320 EeV air shower detected by the Fly's Eye poses an important problem. Careful analysis of pathlength limitations for the possible particle types due to cosmic background radiation verifies that the particle very likely traveled less than 50 Mpc from its source. The best candidates for accelerating particles to s...
1994-10-20
2009-10-22
[ "astro-ph" ]
Jerome W. Elbert and Paul Sommers
astro-ph/9410070
Comments on the Quasi-Steady-State Cosmology
The Quasi-Steady-State Cosmology as proposed by Hoyle, Burbidge and Narlikar does not fit the observed facts of the Universe. In particular, it predicts that 75-90\% of the radio sources in the brightest sample that shows steeper than Euclidean source counts should be blueshifted.
1994-10-20
2015-06-24
[ "astro-ph" ]
Edward L. Wright
astro-ph/9410064
Kinematical Properties of the Thick Disk of the Galaxy
We try here to find new constraints on thick disk population using samples at intermediate latitude and North Galactic Pole, which include photometry and proper motions. The algorithm SEM (Stochastic-Estimation-Maximization; Celeux \& Deibolt 1986) was used to deconvolve the stellar components up to large distances abo...
1994-10-20
2007-05-23
[ "astro-ph" ]
Devendra Ojha
astro-ph/9410063
Starving Accretion Disks in the Center of Galaxies: the Examples of Sgr A* and M31
The low accretion rate inferred for the GC source Sgr A* requires a distinct type of accretion disk -- a starving disk. We investigate the structure of this type of disk within the framework of thin Keplerian disk models taking into account relativistic effects, detailed opacitiy tables and turbulent heat transport. It...
1994-10-20
2007-05-23
[ "astro-ph" ]
H. Falcke and O.M. Heinrich
astro-ph/9410068
Constraints on Cosmological Models from Once and Future Redshift Surveys
The power spectrum of density fluctuations measured from galaxy redshift surveys provides important constraints on models for the formation of large-scale structure. I present new results for a redshift sample of 15,000 galaxies, and review the limitations of current measurements. To span the decade of wavelength betwe...
1994-10-20
2007-05-23
[ "astro-ph" ]
Michael S. Vogeley
astro-ph/9410067
Detection of a Cosmic Ray with Measured Energy Well Beyond the Expected Spectral Cutoff due to Cosmic Microwave Radiation
We report the detection of a 51-joule (320 +/- 90 EeV) cosmic ray by the Fly's Eye air shower detector in Utah. This is substantially greater than the energy of any previously reported cosmic ray. A Greisen-Zatsepin-Kuz'min cutoff of the energy spectrum (due to pion photoproduction energy losses) should occur below thi...
1994-10-20
2009-10-22
[ "astro-ph" ]
D. J. Bird et al. (Utah)
astro-ph/9410056
Automatic Biases Correction
The key point limits to define the {\it statistical model} describing the data distribution. Hence, it turns out that the characteristics related to the so-called. Inverse Tully-Fisher relation and the Direct relation are maximum likelyhood (ML) estimators of different statistical models, and we obtain coherent distanc...
1994-10-19
2007-05-23
[ "astro-ph" ]
R. Triay
astro-ph/9410062
Microlensing by Stars
If stars at the lower end of the main sequence are responsible for the microlensing events observed in the Galactic bulge, then light from the lensing star contributes to the observed brightness. The background and lensing stars generally have different colors, and the relative brightness changes during the microlensin...
1994-10-19
2009-10-22
[ "astro-ph", "hep-ph" ]
Marc Kamionkowski
astro-ph/9410061
The Motions of Clusters and Groups of Galaxies
The distributions of peculiar velocities of rich clusters and of groups of galaxies are investigated for different cosmological models and are compared with observations. Four cosmological models are studied: standard ($\Omega=1$) CDM, low-density ($\Omega=0.3$) CDM, HDM ($\Omega=1$), and PBI ($\Omega=0.3$), all COBE n...
1994-10-19
2009-10-22
[ "astro-ph" ]
Neta A. Bahcall, Mirt Gramann and Renyue Cen
astro-ph/9410059
Mixed Dark Matter models with a non-thermal hot component: fluctuation evolution
We calculate the linear evolution for a class of mixed dark matter models, where the hot component derives from the decay of a heavier particle (CntHDM models). These models differ from ordinary mixed models based on massive neutrinos (CHDM models), for which the hot component has a phase space distribution which deriv...
1994-10-19
2009-09-25
[ "astro-ph" ]
E.Pierpaoli, S.Bonometto
astro-ph/9410060
Big Bang Nucleosynthesis: Consistency Or Crisis ?
The early, hot, dense, expanding Universe was a primordial reactor in which the light nuclides D, 3He, 4He and 7Li were synthesized in astrophysically interesting abundances. The challenge to the standard hot big bang model (Big Bang Nucleosynthesis = BBN) is the comparison between the observed and predicted abundances...
1994-10-19
2007-05-23
[ "astro-ph" ]
Gary Steigman
astro-ph/9410057
Numerical models and our understanding of aspherical Planetary Nebulae
The status of numerical hydrodynamical models for Planetary Nebulae is reviewed. Since all of the numerical work is based on the interacting winds model, we start with a description of this model and give an overview of the early analytical and numerical models. Subsequently we address the numerical models which includ...
1994-10-19
2007-05-23
[ "astro-ph" ]
Garrelt Mellema and Adam Frank
astro-ph/9410058
What's The Problem With ^3He?
We consider the galactic evolutionary history of \he3 in models which deplete deuterium by as much as a factor of 2 to $\sim$ 15 from its primordial value to its present day observed value in the ISM. We show that when \he3 production in low mass stars (1 -- 3 $M_\odot$) is included over the history of the galaxy, \he3...
1994-10-19
2009-09-25
[ "astro-ph" ]
Keith A. Olive, Robert T. Rood, David N. Schramm, James Truran and Elisabeth Vangioni-Flam
astro-ph/9410054
Using SN Ia Light Curve Shapes to Measure The Hubble Constant
We present an empirical method which uses visual band light curve shapes (LCS) to estimate the luminosity of type Ia supernovae (SN Ia). This method is first applied to a ``training set'' of 8 SN Ia light curves with independent distance estimates to derive the correlation between the LCS and the luminosity. We employ ...
1994-10-18
2009-10-22
[ "astro-ph" ]
Adam G. Riess, William H. Press, Robert P. Kirshner
astro-ph/9410053
Acoustic and Thermoreactive Instabilities in a Photoionized Multiphase Medium
We study thermoreactive and acoustic instabilities in a diffuse gas, photoionized and heated by a radiation field. The analysis of the thermal instability by Field (1965) is extended to include the effects of the hydrogen recombination reaction, which, in general, is found to be a stabilizing agent for the condensation...
1994-10-18
2007-05-23
[ "astro-ph" ]
A. Ferrara and E. Corbelli
astro-ph/9410055
The Interstellar $^7$Li/$^6$Li Ratio
We discuss the observational status of the interstellar lithium isotopic ratio and its significance with respect to the galactic evolution of lithium.
1994-10-18
2008-02-03
[ "astro-ph" ]
Martin Lemoine, Roger Ferlet
astro-ph/9410052
Statistics Of Microlensing Optical Depth
We show that the statistical error, $\sigma_{\tau}$, in estimating the optical depth, $\tau$, due to microlensing is substantially higher than the naive Poisson estimate: $\sigma_{\tau} = \sqrt{\eta / N} \tau$, where $N$ is the number of detections and $1.65 \leq \eta \lsim 3$. We construct a ``microlensing map'' using...
1994-10-18
2009-10-22
[ "astro-ph" ]
Cheongho Han and Andrew Gould
astro-ph/9410049
CBR Anisotropy from Primordial Gravitational Waves in Two-Component Inflationary Cosmology
We examine stochastic temperature fluctuations of the cosmic background radiation (CBR) arising via the Sachs-Wolfe effect from gravitational wave perturbations produced in the early universe. We consider spatially flat, perturbed FRW models that begin with an inflationary phase, followed by a mixed phase containing bo...
1994-10-17
2009-10-22
[ "astro-ph" ]
Scott Koranda and Bruce Allen
astro-ph/9410051
Collapse of a Superhorizon-sized Void in the Early Universe
In this paper, we study the collapse of a superhorizon-sized void in the early, radiation-dominated universe using an improved general relativistic code. We find that in general a relativistic or nonrelativistic void collapses via a shock at the speed of light. This is true even if the outward velocity of the void wall...
1994-10-17
2009-10-22
[ "astro-ph", "gr-qc" ]
Sharon L. Vadas
astro-ph/9410050
Companions of Qsos at Redshift 1.1
We discuss broad- and narrow-band imaging of 7 arcmin fields of 14 QSOs with redshift ~1.1. The narrow-band filters were chosen to detect redshifted [O II] 3727A, and the broad bands are R and I, which correspond to rest wavelengths {}~3300A and ~3800A. In 100 arcsec subfields surrounding the QSOs, we detect an excess ...
1994-10-17
2009-10-22
[ "astro-ph" ]
J.B. Hutchings, D. Crampton, Andrea Johnson
astro-ph/9410048
Is There Evidence for Repeating Gamma Ray Bursters in the BATSE Data?
The possibility that classical gamma ray bursts (GRB) occasionally repeat from the same locations on the sky provides a critical test of GRB models. There is currently some controversy about whether there is evidence for burst repetition in the BATSE data. We introduce a gamma ray burst ``pair matching" statistic that ...
1994-10-15
2008-02-03
[ "astro-ph" ]
David P. Bennett and Sun Hong Rhie (CfPA, UC Berkeley, and IGPP, LLNL)
astro-ph/9410044
Evidence for the Galactic Bar from the Two Color Photometry of the Bulge Red Clump Stars
The Optical Gravitational Lensing Experiment (OGLE, Udalski et al.~1994a; Paczy\'nski et al.~1994b -- these proceedings; and references therein) is an extensive photometric search for the rare cases of gravitational microlensing of Galactic bulge stars by foreground objects. It provides a huge data base (Szyma\'nski \&...
1994-10-14
2007-05-23
[ "astro-ph" ]
K. Z. Stanek, M. Mateo, A. Udalski, M. Szymanski, J. Kaluzny, M. Kubiak & W. Krzeminski
astro-ph/9410043
Formation and Evolution of Galaxies: Les Houches Lectures
This is a set of lecture notes based on the lectures on the formation and evolution of galaxies which were given by S. White at Les Houches in August 1993. This postscript file does not contain the 16 figures. A version containing these figures can be obtained by writing to: Fr. C. Rickl, MPI fuer Astrophysik, Karl-Sch...
1994-10-14
2009-09-25
[ "astro-ph" ]
Simon D.M. White
astro-ph/9410047
Gravitational Waves from Wobbling Pulsars
The prospects for detection of gravitational waves from precessing pulsars have been considered by constructing fully relativistic rotating neutron star models and evaluating the expected wave amplitude $h$ from a galactic source. For a "typical" neutron matter equation of state and observed rotation rates, it is shown...
1994-10-14
2016-06-08
[ "astro-ph" ]
J.C.N.de Ara\'ujo, J.A. de Freitas Pacheco, J.E.Horvath and M.Cattani
astro-ph/9410045
Morphology of Galaxy Mergers at Intermediate Redshift
Using a combination of numerical simulation and synthesized Hubble Space Telescope Wide Field Camera 2 (HST WFC2) images, we follow the detectability of morphological signatures of disk galaxy mergers at intermediate redshifts z=0.4 and z=1.0. Rapid evolution in the surface brightness of tidal tails makes their use as ...
1994-10-14
2007-05-23
[ "astro-ph" ]
Chris Mihos
astro-ph/9410046
Combined Stellar Structure and Atmosphere Models: Exploratory Results for Wolf-Rayet Stars
In this paper we present Complete Stellar models (CoStar) for massive stars, which treat the stellar interior and atmosphere, including its wind. Particular emphasis is given to Wolf-Rayet stars. We address the question of the effective temperatures of WNE and WC stars. Our first results show a satisfactory agreement b...
1994-10-14
2007-05-23
[ "astro-ph" ]
D. Schaerer, A. de Koter, and W. Schmutz
astro-ph/9410042
V and I Photometry of Bright Giants in the Central Regions of NGC 147
Deep V and I CCD images with sub-arcsec spatial resolution are used to investigate the stellar content of the central regions of the Local Group dwarf elliptical galaxy NGC147. Red giant branch (RGB) stars are resolved over the entire field, and the RGB-tip occurs at I ~ 20.5, suggesting that the distance modulus is 24...
1994-10-13
2009-10-22
[ "astro-ph" ]
T. J. Davidge
astro-ph/9410040
The Origin of Intermediate-Redshift Lyman Alpha Absorption Systems
We present initial results of an imaging and spectroscopic survey of faint galaxies in fields of Hubble Space Telescope spectroscopic target QSOs. The primary objectives of the survey are (a) to determine the incidence, extent, and covering factor of extended gaseous envelopes of luminous galaxies and (b) to determine ...
1994-10-13
2007-05-23
[ "astro-ph" ]
K.M. Lanzetta, D.V. Bowen, D. Tytler, J.K. Webb and K.M. Sealey
astro-ph/9410041
Surveys for Z>1 Field Galaxies; David Crampton
In the course of the comprehensive CFRS redshift survey to I = 22.5 with the CFHT MOS/SIS spectrograph, we have observed ~25 field galaxies with z > 1. However, it is clear that almost an equal number, predominantly red galaxies, have likely been missed largely because of limitations in the observed wavelength range. T...
1994-10-13
2007-05-23
[ "astro-ph" ]
C.L. Morbey, O. Le Fevre, F. Hammer, L. Tresse, S. J. Lilly and D.J. Schade
astro-ph/9410039
Stationary Universe Model: Inputs and Outputs
This is the text of a talk given at the Rome Conference "The Birth of the Universe and Fundemental Physics", May, 1994. We present the recent progress achieved in collaboration with A.Linde and D.Linde towards understanding the true nature of the global spatial structure of the universe as well as the most general stat...
1994-10-13
2009-10-22
[ "astro-ph", "gr-qc" ]
Arthur Mezhlumian
astro-ph/9410037
Foreground Contributions to 0.2-2 Degree CMB Anisotropies
We examine the extent to which galactic and extragalactic foregrounds can hamper the detection of primordial Cosmic Microwave Background (CMB) anisotropies. We limit our discussion to intermediate angular scales, $10^{\prime}\lsim \theta \lsim 2^{\circ}$, since many current as well as future experiments have been desig...
1994-10-12
2009-09-25
[ "astro-ph" ]
L. Toffolatti, et al
astro-ph/9410036
Non-thermal Acceleration from Reconnection Shocks
Reconnection shocks in a magnetically dominated plasma must be compressive. Non-thermal ion acceleration can occur across built-in slow shocks, and across outflow fast shocks when the outflow is supermagnetosonic and the field is line-tied. Electron acceleration may be initiated by injection from the dissipation region...
1994-10-12
2009-10-22
[ "astro-ph" ]
Eric G. Blackman and George B. Field (Harvard-Smithsonian Center for Astrophysics)
astro-ph/9410035
Deviations from Chemical Equilibrium due to Spin-Down as an Internal Heat Source in Neutron Stars
The core of a neutron star contains several species of particles, whose relative equilibrium concentrations are determined by the local density. As the star spins down, its centrifugal force decreases continuously, and the star contracts. The density of any given fluid element increases, changing its chemical equilibri...
1994-10-12
2009-10-22
[ "astro-ph" ]
Andreas Reisenegger
astro-ph/9410034
Galactic Structure and Stellar Populations
Invited review given at special session on Digitizing the Sky at 1994 Summer AAS meeting, Minnesota.
1994-10-12
2009-10-22
[ "astro-ph" ]
Rosemary F.G. Wyse
astro-ph/9410038
A Solvable Model for Anharmonic Evolution of Cosmic Axion Overdensitites
We present analytic solutions to the spatially homogeneous axion field equation, using a model potential which strongly resembles the $(1-\cos \theta)$ standard anharmonic potential. We find that the anharmonicity amplifies early universe axion density fluctuations, but only significantly so for relatively large initia...
1994-10-12
2009-09-25
[ "astro-ph", "hep-ph" ]
Karl Strobl and Thomas J. Weiler
astro-ph/9410032
Cosmic Strings in an Open Universe with Baryonic and Non-Baryonic Dark Matter
We study the effects of cosmic strings on structure formation in open universes. We calculate the power spectrum of density perturbations for two class of models: one in which all the dark matter is non baryonic (CDM) and one in which it is all baryonic (BDM). Our results are compared to the 1 in 6 IRAS QDOT power spec...
1994-10-11
2009-10-22
[ "astro-ph", "hep-ph" ]
Pedro Ferreira
astro-ph/9410033
The Extragalactic IR Background
Current limits on the intensity of the extragalactic infrared background are consistent with the expected contribution from evolving galaxies. Depending on the behaviour of the star formation rate and of the initial mass function, we can expect that dust extinction during early evolutionary phases ranges from moderate ...
1994-10-11
2009-10-22
[ "astro-ph" ]
G. De Zotti, A. Franceschini, P. Mazzei, L. Toffolatti, and L. Danese
astro-ph/9410031
On the Influence of Supernova Remnant Thermal Energy in Powering Galactic Winds
The fundamental tenet of the classical supernovae-driven wind model of elliptical galaxies is that the residual thermal energy of all supernovae remnants (SNRs) provide sufficient energy to overcome the binding energy of the remaining interstellar gas, thereby driving a global galactic wind. We re-examine model predict...
1994-10-11
2007-05-23
[ "astro-ph" ]
Brad K. Gibson