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astro-ph/9403025
Polarization Profiles of Scattered Emission Lines. I. General Formalism for Optically Thin Rayleigh Scattering
A general theoretical framework is developed for interpreting spectropolarimetric observations of optically thin emission line scattering from small dust particles. Spatially integrated and spatially resolved line profiles of both scattered intensity and polarization are calculated analytically from a variety of simple...
1994-03-11
2009-10-22
[ "astro-ph" ]
W. J. Henney
astro-ph/9403022
Microlensing by Stars in the Disk of M31
The optical depth to microlensing toward M31 due to known stars in the disk of M31 itself is $\tau\sim 2\times 10^{-7}e^{-r/d}$ where $d$ is the disk scale length and $r$ is the distance along the major axis. Thus, there can be significant lensing toward the M31 disk even if M31 contains no dark compact objects. The op...
1994-03-11
2009-10-22
[ "astro-ph" ]
Andrew Gould
astro-ph/9403026
Polarization Profiles of Scattered Emission Lines. II. Upstream Dust Scattering in the HH 1 Jet
Detailed comparisons are made between observations of scattered light upstream of the head of the HH~1 jet and predictions of simple scattering models. It is shown that, in order to unambiguously determine the velocity of the head of the jet (bow shock) with respect to the upstream dust, existing spectroscopic observat...
1994-03-11
2009-10-22
[ "astro-ph" ]
W. J. Henney, A. C. Raga and D. J. Axon
astro-ph/9403016
Lagrangian Evolution of the Weyl Tensor
We derive the evolution equations for the electric and magnetic parts of the Weyl tensor for cold dust from both general relativity and Newtonian gravity. In a locally inertial frame at rest in the fluid frame, the Newtonian equations agree with those of general relativity. We give explicit expressions for the electric...
1994-03-10
2009-10-22
[ "astro-ph", "gr-qc" ]
Edmund Bertschinger and A.J.S. Hamilton
astro-ph/9403019
The Parker instability in disks with differential rotation
We present a detailed study of the growth of the Parker instability in a differentially rotating disk embedded in an azimuthal equilibrium magnetic field, such as the interstellar gas or an accretion disk. Basic properties of the instability without shear are first recalled. Differential rotation is modeled in the shea...
1994-03-10
2007-05-23
[ "astro-ph" ]
T. Foglizzo and M.Tagger
astro-ph/9403021
Correlated Errors in the COBE DMR Sky Maps
The {\it COBE} DMR sky maps contain low-level correlated noise. We obtain estimates of the amplitude and pattern of the correlated noise from three techniques: angular averages of the covariance matrix, Monte Carlo simulations of two-point correlation functions, and direct analysis of the DMR maps. The results from the...
1994-03-10
2009-10-22
[ "astro-ph" ]
C. H. Lineweaver, G. F. Smoot, C. L. Bennett, E. L. Wright, L. Tenorio, A. Kogut, P. B. Keegstra, G. Hinshaw, A. J. Banday
astro-ph/9403020
The Effects of Smoothing on the Statistical Properties of the Large-Scale Cosmic Fileds
It has been shown that the large--scale correlation functions of the density field (and velocity divergence field) follow a specific hierarchy in the quasilinear regime and for Gaussian initial conditions (Bernardeau 1992). The exact relationships between the cumulants of the probability distribution functions (the so-...
1994-03-10
2007-05-23
[ "astro-ph" ]
F. Bernardeau
astro-ph/9403018
Axion String Constraints
We study the production of cosmological axions in the standard scenario in which a global string network forms at the Peccei-Quinn phase transition. We make detailed calculations of the axions produced by string loops (a previously overlooked source), comparing these with estimates of other contributions from long stri...
1994-03-10
2009-10-22
[ "astro-ph", "hep-ph" ]
R.A.Battye and E.P.S.Shellard (DAMTP Cambridge)
astro-ph/9403017
On the spin parameter of dark-matter haloes
The study by White (1984) on the growth of angular momentum in dark haloes is extended towards a more detailed investigation of the spin parameter $\lambda\equiv L\sqrt{E}/{G M^{2.5}}$. Starting from the Zel'dovich approximation to structure formation, a dark halo is approximated by a homogeneous ellipsoid with the ine...
1994-03-10
2015-06-24
[ "astro-ph" ]
Matthias Steinmetz and Matthias Bartelmann
astro-ph/9403014
The Near-IR-Optical-UV Emission of BL Lacertae Objects
Near--infrared, optical and ultraviolet quasi--simultaneous observations of 11 BL Lacertae objects are reported. For all but one source the dereddened spectral flux distribution in the $8\cdot10^{13}-2\cdot10^{15}$ Hz frequency range can be described by a single power law f$_\nu \propto \nu^{-\alpha}$ with average spec...
1994-03-08
2009-10-22
[ "astro-ph" ]
E. Pian, R. Falomo, R. Scarpa & A. Treves
astro-ph/9403015
Amplitudes of Stellar Oscillations: The Implications for Asteroseismology
There are no good predictions for the amplitudes expected from solar-like oscillations in other stars. In the absence of a definitive model for convection, which is thought to be the mechanism that excites these oscillations, the amplitudes for both velocity and luminosity measurements must be estimated by scaling from...
1994-03-08
2011-05-05
[ "astro-ph" ]
H. Kjeldsen and T.R. Bedding
astro-ph/9403009
On the Formation of Elliptical Galaxies
It is shown that the violent relaxation of dissipationless stellar systems leads to universal de Vaucouleurs profiles only outside 1.5 effective radii $R_e$. Inside $1.5 R_e$ the surface density profiles depend strongly on the initial conditions and are in general not in agreement with the de Vaucouleurs law. This resu...
1994-03-07
2007-05-23
[ "astro-ph" ]
Andi Burkert
astro-ph/9403011
Large-amplitude isothermal fluctuations and high-density dark-matter clumps
Large-amplitude isothermal fluctuations in the dark matter energy density, parameterized by $\Phi\equiv\delta\rhodm/\rhodm$, are studied within the framework of a spherical collapse model. For $\Phi \ga 1$, a fluctuation collapses in the radiation-dominated epoch and produces a dense dark-matter object. The final densi...
1994-03-07
2009-10-22
[ "astro-ph" ]
Edward W. Kolb and Igor I. Tkachev
astro-ph/9403013
Magnification Bias in Galactic Microlensing Searches
It is shown that a significant amount of detectable gravitational microlensing events that could potentially be found by MAssively Parallel Photometry (MAPP) projects (such as the MACHO, EROS and OGLE collaborations) will occur for stars too dim to be easily noticed individually by these projects. This is the result of...
1994-03-07
2009-10-22
[ "astro-ph" ]
Robert J. Nemiroff (George Mason University and NASA Goddard Space Flight Center)
astro-ph/9403012
Abundance of moderate-redshift clusters in the Cold + Hot dark matter model
Using a set of $\pppm$ simulation which accurately treats the density evolution of two components of dark matter, we study the evolution of clusters in the Cold + Hot dark matter (CHDM) model. The mass function, the velocity dispersion function and the temperature function of clusters are calculated for four different ...
1994-03-07
2009-10-22
[ "astro-ph" ]
Y.P. Jing and L.Z. Fang
astro-ph/9403010
Is there any Scaling in the Cluster Distribution ?
We apply fractal analysis methods to investigate the scaling properties in the Abell and ACO catalogs of rich galaxy clusters. We also discuss different technical aspects of the method when applied to data sets with small number of points as the cluster catalogs. Results are compared with simulations based on the Zel'd...
1994-03-07
2009-10-22
[ "astro-ph" ]
S.Borgani, V.J. Martinez, M.A.Perez, R.Valdarnini
astro-ph/9403008
Diffuse Molecular Clouds and the Molecular Interstellar Medium from 13CO Observations of M33
We have obtained 12CO and 13CO J=1-0 observations of the nearby spiral galaxy M33 to try to resolve the long-standing discrepancy between 12CO/13CO line ratios measured in Galactic giant molecular clouds and external galaxies. Interferometer maps of the molecular cloud MC20 give a 12CO/13CO line ratio of 7.5+/-2.1, whi...
1994-03-04
2009-10-22
[ "astro-ph" ]
C. D. Wilson and C. E. Walker
astro-ph/9403006
Numerical Methods in Cosmological Global Texture Simulations
Numerical simulations of the evolution of a global topological defect field have two characteristic length scales --- one macrophysical, of order the field correlation length, and the other microphysical, of order the field width. The situation currently of most interest to particle cosmologists involves the behaviour ...
1994-03-03
2010-11-01
[ "astro-ph" ]
Julian Borrill
astro-ph/9403007
Particle Physics and Cosmology
Lectures presented at the 42nd Scottish Universities Summer School in Physics, St. Andrews, Scotland, August 1993.
1994-03-03
2007-05-23
[ "astro-ph" ]
Edward W. Kolb
astro-ph/9403004
Testing Inflation with the Cosmic Microwave Background
Cosmic microwave background (CMB) anisotropy may result from both scalar and tensor perturbations. For a sufficiently narrow range of angular scales, CMB perturbations can be characterized by four parameters. Results from the Cosmic Background Explorer fix one combination of the parameters, reducing the parameters to t...
1994-03-02
2009-10-22
[ "astro-ph" ]
Scott Dodelson, Lloyd Knox, and Edward W. Kolb
astro-ph/9403005
Texture-Induced Microwave Background Anisotropies
We use numerical simulations to calculate the cosmic microwave background anisotropy induced by the evolution of a global texture field, with special emphasis on individual textures. Both spherically symmetric and general configurations are analysed, and in the latter case we consider field configurations which exhibit...
1994-03-02
2009-10-22
[ "astro-ph" ]
Julian Borrill, Edmund J Copeland, Andrew R Liddle, Albert Stebbins and Shoba Veeraraghavan
astro-ph/9403001
Relating Spectral Indices to Tensor and Scalar Amplitudes in Inflation
Within an expansion in slow-roll inflation parameters, we derive the complete second-order expressions relating the ratio of tensor to scalar density perturbations and the spectral index of the scalar spectrum. We find that ``corrections'' to previously derived formulae can dominate if the tensor to scalar ratio is sma...
1994-03-01
2009-10-22
[ "astro-ph", "gr-qc", "hep-ph" ]
Edward W. Kolb and Sharon L. Vadas
astro-ph/9403003
X-Ray and Optical Properties of Groups of Galaxies
We examine the relationship between the group x-ray luminosity in the 0.3-3.5 keV band and the measured velocity dispersion, and galaxy surface number density. We find definite correlations. Richer groups follow the same relation as rich clusters (cf. Quintana & Melnick 1982) with $L_x \propto \sigma^{4.0\pm 0.6}$, but...
1994-03-01
2009-10-22
[ "astro-ph" ]
I.P. Dell'Antonio, M.J. Geller, and D.G. Fabricant
astro-ph/9403002
Boron in the Extreme Pop II Star HD 140283 and the Production of Light Elements in the Early Galaxy
Using observations of the 2496.7 A B I line with the HST GHRS at a nominal resolution of 90,000, we have found the abundance of boron of HD 140283 to be log epsilon_B (= 12 + log (N_B/N_H)) = 0.34 \pm 0.20. This result is found when a significant non-LTE effect in the formation of the B I line is taken into account. Th...
1994-03-01
2007-05-23
[ "astro-ph" ]
B. Edvardsson, B. Gustafsson, S.G. Johansson, D. Kiselman, D.L. Lambert, P.E. Nissen, G. Gilmore
astro-ph/9402071
A ``Skewed'' lognormal approximation to the probability distribution function of the large-scale density field
I propose a method to fit the probability distribution function (hereafter PDF) of the large scale density field rho, motivated by a Lagrangian version of the continuity equation. It consists in applying the Edgeworth expansion to the quantity Phi=log rho - < log rho >. The method is tested on the matter particle distr...
1994-02-28
2009-10-22
[ "astro-ph" ]
S. Colombi
astro-ph/9402070
Simulating Self-gravitating Hydrodynamic Flows
An efficient algorithm for solving Poisson's equation in two and three spatial dimensions is discussed. The algorithm, which is described in detail, is based on the integral form of Poisson's equation and utilizes spherical coordinates and an expansion into spherical harmonics. The solver can be applied to and works we...
1994-02-28
2009-10-22
[ "astro-ph" ]
Ewald Mueller & Matthias Steinmetz
astro-ph/9402069
Merger rates in hierarchical models of galaxy formation. II: Comparison with N-body simulations
We have made a detailed comparison of the results of large N-body simulations with the analytical description of the merging histories of dark matter halos presented in Lacey & Cole 1993, which is based on an extension of the Press- Schechter method (Bond etal 1991,Bower 1991). We find the analytical predictions for th...
1994-02-28
2015-06-24
[ "astro-ph" ]
Cedric Lacey and Shaun Cole
astro-ph/9402068
Ohm's Law for a Relativistic Pair Plasma
We derive the fully relativistic Ohm's law for an electron-positron plasma. The absence of non-resistive terms in Ohm's law and the natural substitution of the 4-velocity for the velocity flux in the relativistic bulk plasma equations do not require the field gradient length scale to be much larger than the lepton iner...
1994-02-27
2009-10-22
[ "astro-ph" ]
Eric G. Blackman and George B. Field (Harvard Univ.)
astro-ph/9402065
Non-Linear Approximations to Gravitational Instability: A Comparison in the Quasi-Linear Regime
We compare different nonlinear approximations to gravitational clustering in the weakly nonlinear regime, using as a comparative statistic the evolution of non-Gaussianity which can be characterised by a set of numbers $S_p$ describing connected moments of the density field at the lowest order in $<\delta^2>$: $<\delta...
1994-02-25
2009-10-22
[ "astro-ph" ]
Dipak Munshi, Varun Sahni and Alexei A. Starobinsky
astro-ph/9402062
Smoothed Particle Interpolation
Smoothed particle hydrodynamics (SPH) discretization techniques are generalized to develop a method, smoothed particle interpolation (SPI), for solving initial value problems of systems of non-hydrodynamical nature. Under this approach, SPH is viewed as strictly an interpolation scheme and, as such, suitable for solvin...
1994-02-25
2009-10-22
[ "astro-ph" ]
Pablo Laguna (Penn State Univ.)
astro-ph/9402063
Evolution of Galaxies in Clusters
We use new models of stellar population synthesis to estimate the fraction of stars formed during the last major bursts of star formation in E/S0 galaxies in low-redshift clusters ($z\simlt0.4$) from the spectral signatures of intermediate-age stars. We find that the mass fraction of stars formed in late bursts in earl...
1994-02-25
2009-10-22
[ "astro-ph" ]
S. Charlot and J. Silk
astro-ph/9402066
Collapse of Axionic Domain Wall and Axion Emission
We examine the collapse of an axion domain wall bounded by an axionic string. It is found that the collapse proceeds quickly and axion domain walls disappear. However axions are emitted in the collapse and its energy density increases during radiation dominated era and contributes significantly to the present mass dens...
1994-02-25
2009-10-22
[ "astro-ph" ]
Michiyasu Nagasawa and Masahiro Kawasaki
astro-ph/9402061
Short time scale monitoring of SiO sources
We present the results of a short time scale monitoring of SiO maser emission (v=1 J=1-0 transition) in four known strong sources. These sources were monitored nightly for a period of about a month. The aim of these observations is to investigate the possible presence of variations in the maser lines on time scales of ...
1994-02-24
2007-05-23
[ "astro-ph" ]
F.P. Pijpers, J.R.Pardo, V. Bujarrabal
astro-ph/9402059
Non-Gaussian statistics of pencil beam surveys
We study the effect of the non-Gaussian clustering of galaxies on the statistics of pencil beam surveys. We find that the higher order moments of the galaxy distribution play an important role in the probability distribution for the power spectrum peaks. Taking into account the observed values for the kurtosis of galax...
1994-02-24
2009-10-22
[ "astro-ph" ]
Luca Amendola
astro-ph/9402067
Lick Optical Spectra of Quasar HS 1946+7658 at 10 km/sec Resolution: Lyman-Alpha Forest and Metal Absorption Systems
We present optical spectra of QSO HS~1946+7658 with either high resolution (FWHM=10 km/s) or high signal to noise ratio (SNR=40-100). We find 113 Lyman alpha and six metal line systems. The metal systems at Zabs=2.844 and 3.050 have complex velocity structures. We find that the system at 2.844 is a damped Ly-a absorpti...
1994-02-24
2010-12-16
[ "astro-ph" ]
X.-M. Fan and D. Tytler
astro-ph/9402060
Microwave Background Fluctuations in an Open Universe
( to appear in: Proceedings of the Nishonomiya Yukawa Memorial Symposium Edited by M. Sasaki) There are several models for generating fluctuations in an open universe that are compatible with the microwave background fluctuations detected by COBE {\it and} observations of large scale structure. Topological defects, suc...
1994-02-24
2009-09-25
[ "astro-ph", "hep-ph" ]
David N. Spergel, Ue-Li Pen, Marc Kamionkowski, Naoshi Sugiyama
astro-ph/9402064
Fabry-Perot Measurements of the Dynamics of Globular Cluster Cores: M15 (NGC~7078)
We report the first use of the Rutgers Imaging Fabry-Perot Spectrophotometer to study the dynamics of the cores of globular clusters. We have obtained velocities for cluster stars by tuning the Fabry-Perot to take a series of narrow-band images at different wavelengths across one of the Na D (5890 AA) absorption lines....
1994-02-24
2009-10-22
[ "astro-ph" ]
K. Gebhardt, C. Pryor, T.B. Williams, and J.E. Hesser
astro-ph/9402057
Comparison of Dynamical Approximation Schemes for Non-Linear Gravitational Clustering
I report on controlled comparison of gravitational approximation schemes linear/lognormal/adhesion/frozen-flow/Zel'dovich(ZA) and ZA's second--order generalization. In the last two cases we also created new versions of the approximation by truncation, i.e., by finding an optimum smoothing window (see text) for the init...
1994-02-23
2009-10-22
[ "astro-ph" ]
Adrian L. Melott
astro-ph/9402058
Substructure in Clusters and Central Galaxy Peculiar Velocities
Formation theories for central dominant galaxies in clusters require them to be located at the minimum of the cluster gravitational potential. However, 32\% (8 out of 25) of the clusters with more than 50 measured redshifts have central galaxies with significant velocity offsets (with respect to other cluster members)....
1994-02-23
2009-10-22
[ "astro-ph" ]
Christina M. Bird
astro-ph/9402056
A search for symbiotic behaviour amongst OH/IR colour mimics
Recent maser surveys have shown that many potential OH/IR stars have no OH masers in their circumstellar envelopes, despite the modest requirements which should be implicitly met by IRAS colour-selected candidates. It has been suggested that these OH/IR colour mimics must have a degenerate companion which dissociates O...
1994-02-22
2015-06-24
[ "astro-ph" ]
E. R. Seaquist and R. J. Ivison
astro-ph/9402055
Discovery of hydroxyl and water masers in R Aquarii and H1-36 Arae
We present the first results from an all-sky maser-line survey of symbiotic Miras. Interferometric spectral-line observations of R Aqr and H1-36 Arae have revealed a 22-GHz water maser in the former and 1612-MHz hydroxyl and weak 22-GHz water maser emission from the latter. H1-36 has thus become the first known symbiot...
1994-02-22
2015-06-24
[ "astro-ph" ]
R. J. Ivison, E. R. Seaquist and P. J. Hall
astro-ph/9402054
Evidence for Hco+ Infall toward T Tauri?
High spectral and spatial resolution observations of the HCO+ molecule toward the T Tau binary system obtained with the Owens Valley Millimeter Array reveal a broad emission line profile (V_LSR = 7.2 km/s, width = 2.0 km/s) upon which a narrow, redshifted absorption feature (V_LSR = 8.5 km/s, width +/- 0.5 km/s) is sup...
1994-02-22
2009-10-22
[ "astro-ph" ]
Huib Jan van Langevelde, Ewine F. van Dishoeck, Geoffrey A. Blake
astro-ph/9402048
Gravitational Lensing of Distant Field Galaxies by Rich Clusters: I. -- Faint Galaxy Redshift Distributions
{}From deep optical images of three clusters selected by virtue of their X-ray luminosity and/or optical richness (1455+22; $z=0.26$, 0016+16; $z=0.55$ and 1603+43; $z=0.89$), we construct statistically-complete samples of faint field galaxies ($I \leq 25$) suitable for probing the effects of gravitational lensing. By ...
1994-02-21
2015-06-24
[ "astro-ph" ]
Ian Smail, Richard S. Ellis & Michael J. Fitchett
astro-ph/9402052
Typical Scales in the Spatial Distribution of QSOs
We present results of searching for the possible typical scales in the spatial distribution of QSOs. Our method is based on the second derivative of the two-point correlation function. This statistic is sensitive to the scale of the maximum in the spectrum $P(k)$ of the density perturbation in the universe. This maximu...
1994-02-21
2009-10-22
[ "astro-ph" ]
Zugan Deng, Xiaoyang Xia and Li-Zhi Fang
astro-ph/9402051
Spherical Accretion onto Neutron Stars Revisited: Are Hot Solutions Possible ?
Stationary, spherical accretion onto an unmagnetized neutron star is here reconsidered on the wake of the seminal paper by Zel'dovich \& Shakura (1969). It is found that new ``hot'' solutions may exist for a wide range of luminosities. These solutions are characterized by a high temperature, $10^{9}\div 10^{11}$ K, and...
1994-02-21
2009-10-22
[ "astro-ph" ]
Roberto Turolla, Luca Zampieri, Monica Colpi and Aldo Treves
astro-ph/9402053
Noise Correlation in Cosmic Microwave Background Experiments
Many analyses of microwave background experiments neglect the correlation of noise in different frequency or polarization channels. We show that these correlations, should they be present, can lead to severe misinterpretation of an experiment. In particular, correlated noise arising from either electronics or atmospher...
1994-02-21
2009-10-22
[ "astro-ph" ]
Scott Dodelson (Fermilab), Arthur Kosowsky (Chicago) and Steven T. Myers (Caltech)
astro-ph/9402049
Gravitational Lensing of Distant Field Galaxies by Rich Clusters: II. -- Cluster Mass Distributions
Using a non-parametric procedure developed by Kaiser \& Squires (1993), we analyse the statistical image distortions of faint field galaxies to $I\ls25.5$ in two distant X-ray luminous clusters 1455+22 ($z_{cl}=0.26$) and 0016+16 ($z_{cl}=0.55$) to derive two dimensional projected mass distributions for the clusters. T...
1994-02-21
2015-06-24
[ "astro-ph" ]
Ian Smail, Richard S. Ellis, Michael J. Fitchett & Alastair C. Edge
astro-ph/9402050
The Formation of Galaxies: A Challenge for Supercomputers -- a Simple Task for GRAPE ?
We present numerical simulations of galaxy formation, one of the most challenging problems in computational astrophysics. The key point in such simulations is the efficient solution of the N--body problem. If the gas of a galaxy is treated by means of smoothed particle hydrodynamics (SPH), the hydrodynamic equations ca...
1994-02-21
2007-05-23
[ "astro-ph" ]
Matthias Steinmetz
astro-ph/9402047
Is the High-Energy Emission from Centaurus A Compton-Scattered Jet Radiation?
We consider whether the hard X-ray and soft gamma-ray emission from Centaurus A is beamed radiation from the active nucleus which is Compton-scattered into our line-of-sight. We derive the spectrum and degree of polarization of scattered radiation when incident beamed radiation is scattered from a cold ($kT<<m_ec^2$) e...
1994-02-18
2009-10-22
[ "astro-ph" ]
J. G. Skibo, C. D. Dermer and R. L. Kinzer
astro-ph/9402046
Are Analogues of Hot Subdwarf Stars Responsible for the UVX Phenomenon in Galaxy Nuclei?
We present the case that populations of sdB/sdOB/sdO-type stars may be a common constituent of galactic stellar populations, responsible for the UV upturn (`UVX') observed in the spectra of spiral bulges and normal galaxy nuclei. Extreme Horizontal Branch stars with $\log g > 5$ and $\log \teff > 20,000K$ have emerged ...
1994-02-18
2007-05-23
[ "astro-ph" ]
Ben Dorman, R.W. O'Connell, & R.T. Rood (Astronomy Dept, University of Virginia.)
astro-ph/9402044
Topological Defects in an Open Universe
(To appear in Nuclear Physics B Supplements Proceedings section) This talk will explore the evolution of topological defects in an open universe. The rapid expansion of the universe in an open model slows defects and suppresses the generation of CBR fluctuations at large angular scale as does the altered relationship b...
1994-02-17
2009-10-22
[ "astro-ph" ]
David N. Spergel and Ue-Li Pen
astro-ph/9402045
Power Spectrum Constraints from Spectral Distortions in the Cosmic Microwave Background
%The content of this replacement paper is identical to the original. %We have attempted to fix the postscript so that it will print out on %a larger number of printers. Using recent experimental limits on $\mu$ distortions from COBE FIRAS, and the large lever-arm spanning the damping of sub-Jeans scale fluctuations to ...
1994-02-17
2009-10-22
[ "astro-ph" ]
Wayne Hu, Douglas Scott, & Joseph Silk
astro-ph/9402039
A General Class of Self-similar Self-gravitating Fluids
(accepted for publication in the Ap.J.) I present a general classification of self-similar solutions to the equations of gravitational hydrodynamics that contain many previous results as special cases. For cold flows with spherical symmetry, the solution space can be classified into several regions of behavior similar ...
1994-02-16
2009-10-22
[ "astro-ph" ]
Ue-Li Pen
astro-ph/9402042
Interactions of Cosmic Ray Nuclei
We present convenient formulae for the energy losses of energetic atomic nuclei over the entire energy range relevant to the physics of cosmic rays. Results are applied to a leaky-box equation with a complete loss term. Thereby we derive the equilibrium spectrum of cosmic rays in various types of galaxies. We emphasize...
1994-02-16
2007-05-23
[ "astro-ph" ]
K. Mannheim and R. Schlickeiser
astro-ph/9402043
CMB Broad-Band Power Spectrum Estimation
The natural outcome of theoretical calculations of microwave background anisotropy is the angular power spectrum ${\cal C}_\ell$ as a function of multipole number $\ell$. Experimental ${\cal C}_\ell$'s are needed for direct comparison. Estimation procedures using statistics linear in the pixel amplitudes as well as the...
1994-02-16
2009-09-25
[ "astro-ph" ]
J. Richard Bond
astro-ph/9402040
The contribution of galaxies to OMEGA_0
We estimate the contribution of galaxies to the cosmological density Omega_0 including also their extended dark halos. We find Omega_gal< 0.1, so implying that the matter in galaxies cannot by itself close the Universe but marginally could be baryonic. (latex file)two figures available upon request).
1994-02-16
2007-05-23
[ "astro-ph" ]
Paolo Salucci, Massimo Persic
astro-ph/9402041
How Well Can Cosmological Parameters Be Estimated from CMB Observations?
The CMB anisotropy depends sensitively upon the slope and amplitude of primordial density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history, {\it etc.} We report on recent work showing how well multi-scale measurements of the anisotropy power...
1994-02-16
2009-09-25
[ "astro-ph", "gr-qc" ]
J. Richard Bond, Richard L. Davis, and Paul J. Steinhardt
astro-ph/9402037
Window Functions for CMB Experiments
We discuss the applicability and derivation of window functions for cosmic microwave background experiments on large and intermediate angular scales. These window functions describe the response of the experiment to power in a particular mode of the fluctuation spectrum. We give general formulae, illustrated with speci...
1994-02-15
2008-11-26
[ "astro-ph" ]
Martin White and Mark Srednicki
astro-ph/9402038
Reconstructing the CMB power spectrum
We discuss a method for a model independent reconstruction of the CMB temperature fluctuation power spectrum on small and intermediate scales that is geared to individual experiments. The importance of off-diagonal correlations for determining the shape of the power spectrum is emphasized and some examples of a reconst...
1994-02-15
2009-09-25
[ "astro-ph" ]
Martin White
astro-ph/9402034
Giant Explosion at the Galactic Center and Huge Shocked Shells in the Halo
We simulate the propagation of a shock front through the galactic halo induced by an explosion and/or a starburst at the galactic center. A huge dumbbell ($\Omega$)-shaped shock front produced by an explosion of energy $3\times 10^{56}$ ergs about fifteen million years ago can mimic the radio and X-ray North Polar Spur...
1994-02-14
2009-10-22
[ "astro-ph" ]
Yoshiaki SOFUE
astro-ph/9402036
Lensing from the Light-Traces-Mass Map of MS1224+20
The MS1224+20 cluster of galaxies is a high luminosity X-ray source at z=0.325. To compare the lensing mass to the virial mass we have completed a uniform, high precision redshift survey over a field of $7\arcm\times9\arcm$, obtaining 75 redshifts. The velocity dispersion of 30 cluster galaxies is $775$ \kms\ and the p...
1994-02-14
2009-10-22
[ "astro-ph" ]
R. G. Carlberg, H. K. C. Yee, and E. Ellingson
astro-ph/9402035
The Gunn-Peterson Effect in the Spectrum of the Z=4.7 QSO 1202-0725: The Intergalactic Medium at Very High Redshift
A measure of the average depression between Lyman absorption lines in the spectrum of the faint quasar BR1202-0725 ($z_{em}=4.695$) is presented. The relatively high resolution of the spectrum ($\sim 40$ km s$^{-1}$) allows the selection of regions free of strong absorption lines in the Lyman alpha forest. A reliable e...
1994-02-14
2009-10-22
[ "astro-ph" ]
E. Giallongo, S. D'Odorico, A. Fontana, R. G. McMahon, S. Savaglio, S. Cristiani, P.Molaro, D. Trevese
astro-ph/9402033
A Singularity-Free Cosmological Model with a Conformally Coupled Scalar Field
We explore the possibility of describing our universe with a singularity--free, closed, spatially homogeneous and isotropic cosmological model, using only general relativity and a suitable equation of state which produces an inflationary era. A phase transition to a radiation--dominated era occurs as a consequence of b...
1994-02-13
2010-11-01
[ "astro-ph" ]
S.S. Bayin, F.I. Cooperstock and V. Faraoni
astro-ph/9402032
How Cosmic Background Correlations at Large Angles Relate to Mass Autocorrelations in Space
The Sachs-Wolfe effect is known to produce large angular scale fluctuations in the Cosmic Microwave Background Radiation (CMBR) due to gravitational potential fluctuations. We show how the angular correlation function of the CMBR can be expressed explicitly in terms of the mass autocorrelation function $\xi (r)$ in the...
1994-02-12
2009-10-22
[ "astro-ph" ]
George R. Blumenthal and Kathryn V. Johnston
astro-ph/9402030
Multiple High-Velocity Emission-Line Systems in the E+S Pair CPG 29
A detailed study of the mixed-morphology galaxy pair CPG 29 (Arp 119, VV 347) shows spectacular spectroscopic peculiarities in the southern (spiral) component (Mkn 984) including a spatially resolved region, roughly aligned along the minor axis of the galaxy, with multiple emission-line components redshifted by as much...
1994-02-11
2009-10-22
[ "astro-ph" ]
P. Marziani, W. C. Keel, D. Dultzin--Hacyan, and J. W. Sulentic
astro-ph/9402031
Monopoles as Big as a Universe
We show that, contrary to the standard belief, primordial monopoles expand exponentially during inflation in the new inflationary universe scenario. Moreover, inflation of monopoles continues without an end even when inflation ends in the surrounding space. Therefore primordial monopoles (as well as other topological d...
1994-02-11
2009-09-29
[ "astro-ph", "hep-ph", "hep-th" ]
Andrei Linde
astro-ph/9402028
Is a Massive Tau Neutrino Just What Cold Dark Matter Needs?
The cold dark matter (CDM) scenario for structure formation in the Universe is very attractive and has many successes; however, when its spectrum of density perturbations is normalized to the COBE anisotropy measurement the level of inhomogeneity predicted on small scales is too large. This can be remedied by a tau neu...
1994-02-11
2009-10-22
[ "astro-ph" ]
Scott Dodelson, Geza Gyuk, and Michael S. Turner
astro-ph/9402029
Microlensing by brown dwarfs: the case of dark clusters
Experiments are looking for diffuse brown dwarfs in the dark galactic halo through the gravitational lens effect. If brown dwarfs are clumped in dark clusters, the event rate is not changed, but events are spatially clustered, and stars nearby a micro-lensed one are likely to be micro-lensed in a near future. Therefore...
1994-02-11
2007-05-23
[ "astro-ph" ]
Alain Bouquet, Jean Kaplan and Jean-Manuel Verschaeve
astro-ph/9402025
The Distribution of Galactic Disk Stars in Baade's Window
The color-magnitude diagram of $ \sim 3 \times 10^5 $ stars obtained for Baade's Window towards the Galactic bulge with the OGLE project reveals a surprisingly narrow main sequence due to galactic disk stars at a distance of $d \sim 2 $ kpc, i.e. at the location of the Sagittarius spiral arm. A more careful analysis in...
1994-02-09
2009-10-22
[ "astro-ph" ]
B. Paczynski, K.Z. Stanek, A. Udalski, M. Szymanski, J. Kaluzny, M. Kubiak and M. Mateo
astro-ph/9402026
An Alternative View of Flat Rotation Curves. II. The Observations
The rotation curves of 20 spiral galaxies are examined in the light of a toy model (Soares 1992) which has as the main feature the assignment of a high M/L ratio (=30; Ho=50 km/s/Mpc) to the visible matter. The observed rotation of all galaxies can be accommodated without the assumption of a dark halo. Moreover, the ...
1994-02-09
2009-09-25
[ "astro-ph" ]
D.S.L. Soares
astro-ph/9402027
Gravitational Microlensing by Dark Clusters in the Galactic Halo
The dark matter in Galactic halos, or some fraction of it, may be in the form of dark clusters which consist of small mass objects. Carr & Lacey (1987) have derived the permissible properties of such systems, and proposed the existence of dark clusters with mass of order $10^6\solarmass$ to explain some of the observed...
1994-02-09
2009-10-22
[ "astro-ph" ]
Eyal Maoz
astro-ph/9402024
Spectral Analysis of Microwave Background Perturbations Induced by Cosmic Strings
Using a simple analytic model based on seed superposition we obtain the spectrum of microwave background perturbations induced by cosmic strings on all angular scales larger than about 2 armin. We assume standard recombination in an Einstein de Sitter universe with $h=1/2$ and study the fluctuation spectrum along a gre...
1994-02-09
2011-05-10
[ "astro-ph", "hep-ph" ]
Leandros Perivolaropoulos (Harvard-Smithsonian CfA)
astro-ph/9402023
Signatures of Cosmic Strings on the Microwave Background
ABSRACT: We review recent progress on testing the hypothesis of the existence of cosmic string perturbations in microwave background maps. Using an analytical model for the string network we show that the predicted amplitude and spectrum of MBR fluctuations are consistent with the COBE data for a reasonable value of th...
1994-02-09
2009-09-25
[ "astro-ph" ]
Leandros Perivolaropoulos (Harvard-Smithsonian CfA), Richhild Moessner (Brown U.) and Robert Brandenberger (Brown U.)
astro-ph/9402019
Computational aspects of the gravitational instability problem for a multicomponent cosmological medium
The paper presents results for deriving closed-form analytic solutions of the non-relativistic linear perturbation equations, which govern the evolution of inhomogeneities in a homogeneous spatially flat multicomponent cosmological model. Mathematical methods to derive computable forms of the perturbations are outlined...
1994-02-08
2009-10-22
[ "astro-ph" ]
H.J.Haubold and A.M.Mathai
astro-ph/9402021
Second-Order Reconstruction of the Inflationary Potential
To first order in the deviation from scale invariance the inflationary potential and its first two derivatives can be expressed in terms of the spectral indices of the scalar and tensor perturbations, $n$ and $n_T$, and their contributions to the variance of the quadrupole CBR temperature anisotropy, $S$ and $T$. In ad...
1994-02-08
2014-10-13
[ "astro-ph", "hep-ph" ]
Andrew R Liddle and Michael S Turner
astro-ph/9402018
Anisotropic Scattering of OH/IR Stars Towards the Galactic Center
We have made angular broadening measurements in the satellite line of the OH molecule at 1612 MHz of 8 OH/IR stars located near the Galactic Center with the Very Large Array. Early observations with the Very Long Baseline Array had revealed a region of pronounced scattering approximately centered on SgrA*. These new ob...
1994-02-08
2009-10-22
[ "astro-ph" ]
D. A. Frail, P. J. Diamond, J. M. Cordes and H. J. Van Langevelde
astro-ph/9402020
Astrophysical thermonuclear functions
As theoretical knowledge and experimental verification of nuclear cross sections increases it becomes possible to refine analytic representations for nuclear reaction rates. In this paper mathematical/statistical techniques for deriving closed-form representations of thermonuclear functions are summarized and numerical...
1994-02-08
2009-10-22
[ "astro-ph" ]
W.J. Anderson, H.J. Haubold, and A.M. Mathai
astro-ph/9402022
High Resolution Observations of Cepheus a
New high resolution 6 cm observations have been made on Cepheus A using MERLIN, and combined with new VLA observations at 3.7 cm. Angular resolution with the latter was 200 mas, and with MERLIN was 60 mas, except for isolated unresolved sources where 33 mas was achieved. Unresolved objects at 60 mas were observed in So...
1994-02-08
2015-06-24
[ "astro-ph" ]
V. A. Hughes, R. J. Cohen, and S. Garrington
astro-ph/9402017
Dark Matter in ms1224 from Distortion of Background Galaxies
We explore the dark matter distribution in ms1224.7+2007 using the gravitational distortion of the images of faint background galaxies. Projected mass image reconstruction reveals a highly significant concentration coincident with the X-ray and optical location. The concentration is seen repeatably in reconstructions f...
1994-02-08
2009-10-22
[ "astro-ph", "hep-ph" ]
G.G. Fahlman, Nick Kaiser, Gordon Squires and David Woods
astro-ph/9402016
Photometric and H$\alpha$ observations of LSI+61303: detection of a $\sim$26 day V and JHK band modulation
We present new optical and infrared photometric observations and high resolution H$\alpha$ spectra of the periodic radio star \lsi. The optical photometric data set covers the time interval 1985-1993 and amounts to about a hundred nights. A period of $\sim$26 days is found in the V band. The infrared data also present ...
1994-02-07
2007-05-23
[ "astro-ph" ]
J. M. Paredes, P. Marziani, J. Marti, J. Fabregat, M. J. Coe, C. Everall, F. Figueras, C. Jordi, A. J. Norton, T. Prince, V. Reglero, P. Roche, J. Torra, S. J. Unger and R. Zamanov
astro-ph/9402014
Damped Lyman Alpha Systems and Galaxy Formation
We examine the constraints on theories of galaxy formation that are obtained from observations of damped $\lya$ (DL) systems, assuming they are gaseous protodisks in dark matter halos. Using the Press-Schechter formalism, we find that the mixed dark matter model, with $\ohdm = 0.3$, $\ocdm = 0.65$, $\obaryon = 0.05$, a...
1994-02-04
2009-10-22
[ "astro-ph" ]
H.J. Mo and J. Miralda-Escude
astro-ph/9402012
A Century of Gamma Ray Burst Models
More than 100 gamma-ray burst progenitor models have now been published in refereed journals. A list of the models published before the end of 1992 is presented and briefly discussed. The consensus of the present astronomical community remains that no specific model is particularly favored for cosmic bursts. Recent BAT...
1994-02-04
2007-05-23
[ "astro-ph" ]
Robert J. Nemiroff (NASA/GSFC and George Mason U.)
astro-ph/9402015
Constraints on Models of Galaxy Formation from the Evolution of Damped Ly$\alpha$ Absorption Systems
There is accumulating observational evidence suggesting that damped Ly$\alpha$ absorption systems systems are the progenitors of present-day spiral galaxies. We use the observed properties of these systems to place constraints on the history of star formation in galactic disks, and on cosmological theories of structure...
1994-02-04
2016-08-14
[ "astro-ph" ]
Guinevere Kauffmann and St\'ephane Charlot
astro-ph/9402013
The spectrum of Sgr A* and its variability
We demonstrate that there is only one physical process required to explain the spectrum and the variability of the radio source at the dynamical center of our Galaxy, Sgr A*, in the frequency range from $\approx$1 to $\approx$1000 GHz, namely optically thin synchrotron radiation that is emitted from a population of rel...
1994-02-04
2007-05-23
[ "astro-ph" ]
Wolfgang J. Duschl and Harald Lesch
astro-ph/9402009
The Nature Of Dark Matter
Collisionless particles, such as cold dark matter, interact only by gravity and do not have any associated length scale, therefore the dark halos of galaxies should have negligible core radii. This expectation has been supported by numerical experiments of collisionless particles within scale free and cold dark matter ...
1994-02-03
2009-09-25
[ "astro-ph", "gr-qc", "hep-ph" ]
Ben Moore
astro-ph/9402011
Low Frequency Quasi-Periodic Oscillations in Low Mass X-Ray Binaries and Galactic Black Hole Candidates
We consider the inner regions of accretion disks surrounding black holes and neutron stars and investigate the nonlinear time dependent evolution of thermal-viscous instabilities. The viscous stress is assumed to be proportional to the gas pressure with the viscosity parameter formulated as $\alpha =\min[\alpha_0 (h/r)...
1994-02-03
2009-10-22
[ "astro-ph" ]
Xingming Chen and Ronald E. Taam (Northwestern U)
astro-ph/9402010
Refined Big Bang Nucleosynthesis Constraints on $\Omega_{Baryon}$ and $N_{\nu}$
We include correlations between elemental abundances in a Monte Carlo statistical analysis of BBN predictions, which, along with updated reaction rates and an improved BBN code, lead to tightened constraints on $\Omega_{B}$ and $N_{\nu}$. Observational upper limits on the primordial \he and $\rm {D + {^3He}}$ fractions...
1994-02-03
2009-10-22
[ "astro-ph", "hep-ph", "nucl-th" ]
Peter J. Kernan and Lawrence M. Krauss
astro-ph/9402005
Far-IR Properties of Early Type Galaxies
We have investigated the IRAS colours and the far-IR to optical luminosity ratios of a complete sample of elliptical's and S0's brighter than $B_T = 12$. On the average, elliptical galaxies emit in the far-IR less than 1\% of their bolometric luminosity, while S0's are about a factor of three brighter in the far-IR. On...
1994-02-02
2009-10-22
[ "astro-ph" ]
P. Mazzei and G. De Zotti
astro-ph/9402003
Shear Fields and the Evolution of Galactic-Scale Density Peaks
We present preliminary results of our investigation into the influence of shear fields on the evolution of galactic scale fluctuations in a primordial Gaussian random density field. Specifically, we study how the matter associated with a galaxy-scale peak evolves, to determine whether the shear can affect the peak's ab...
1994-02-02
2009-10-22
[ "astro-ph" ]
Rien van de Weygaert and Arif Babul
astro-ph/9402006
Constraints on the Models for Structure Formation from the Abundance of Damped Lyman Alpha Systems
Models for structure formation attempt to predict the power spectrum of density perturbations in the present universe from the initial power spectrum and the nature of dark matter. Observational constraints on the power spectrum at different scales in the present epoch can, therefore, be used to eliminate (or choose be...
1994-02-02
2007-05-23
[ "astro-ph", "gr-qc" ]
K.Subramanian and T.Padmanabhan
astro-ph/9402007
Search For Unresolved Sources In The COBE-DMR Two-Year Sky Maps
We have searched the temperature maps from the COBE Differential Microwave Radiometers (DMR) first two years of data for evidence of unresolved sources. The high-latitude sky (|b| > 30\deg) contains no sources brighter than 192 uK thermodynamic temperature (322 Jy at 53 GHz). The cumulative count of sources brighter th...
1994-02-02
2009-10-22
[ "astro-ph" ]
A. Kogut, A.J. Banday, C.L. Bennett, G. Hinshaw, K. Loewenstein, P. Lubin, G.F. Smoot, and E.L. Wright
astro-ph/9402008
Is There a Planet in the PSR 1620-26 Triple System?
The unusually large eccentricity ($e_1=0.025$) of the low-mass binary millisecond pulsar PSR B1620-26 can be explained naturally as arising from the secular perturbation of a second, more distant companion. Such a triple configuration has been proposed recently as the most likely cause of the anomalous second period de...
1994-02-02
2009-10-22
[ "astro-ph" ]
F. A. Rasio
astro-ph/9402004
Observational and Theoretical Constraints on Singular Dark Matter Halos
The distribution of dark matter around galactic or cluster halos has usually been assumed to be approximately isothermal with a non-zero core radius, which is expected to be of the order of the size of the visible matter distribution. Recently, the possibility has been raised that dark matter halos might be singular in...
1994-02-02
2009-10-22
[ "astro-ph", "hep-ph" ]
Ricardo A. Flores and Joel R. Primack
astro-ph/9402002
Hydrogen Clouds and the MACHO/EROS Events
We propose that the recently reported MACHO/EROS events correspond to gravitational amplification by dark clouds rather than compact objects. These clouds must be very dense with $M\sim 0.1 ~M_\odot$ and $R\la 10^{14}~{\rm cm}$. In all likelihood, the clouds will be members of a family of objects with different sizes a...
1994-02-01
2009-10-22
[ "astro-ph" ]
Richard N. Henriksen and Lawrence M. Widrow
astro-ph/9402001
A Recipe for Galaxy Formation Shaun Cole
We present a detailed prescription for how galaxy formation can be modelled in hierarchical theories of structure formation. Our model incorporates the formation and merging of dark matter halos, the shock heating and radiative cooling of baryonic gas gravitationally confined in these halos, the formation of stars regu...
1994-02-01
2015-06-24
[ "astro-ph" ]
Alfonso Aragon-Salamanca, Carlos S. Frenk, Julio F. Navarro and Stephen E. Zepf
astro-ph/9401051
A Survey of Faint Galaxy Pairs
A sample of faint, V magnitude selected, galaxy pairs, having physical separations less than approximately 20\hkpc, is used to examine the rise in the merger rate with redshift and the statistical relations between close pairs and the field galaxy population. Redshifts have been obtained for 14 galaxies ($V \le 22.5$) ...
1994-01-31
2009-10-22
[ "astro-ph" ]
Carlberg, Pritchet and Infante
astro-ph/9401050
Limits on Direct Detection of Gravitational Waves
We compute energy density and strain induced by a primordial spectrum of gravitational waves on terrestrial- and space-based detectors (e.g., LIGO) as constrained by the COBE detection of microwave background anisotropy. For the case where the spectrum is created during inflation, we find new, stricter upper bounds on ...
1994-01-28
2009-10-22
[ "astro-ph", "gr-qc" ]
R. Bar-Kana
astro-ph/9401048
Scale-Invariant Spectrum of Cosmic Background Radiation as a Feature of the Universe with Negative Curvature
As was shown before (Gurzadyan and Kocharyan, 1992, 1993ab) the statistical properties (exponential mixing) of motion of CMB photon beams in Friedmann Universe with negative curvature can have definite observable consequences including the decrease of the CMB anisotropy amplitude after the last scattering, distortion o...
1994-01-28
2008-02-03
[ "astro-ph" ]
V.G.Gurzadyan and A.A.Kocharyan
astro-ph/9401049
Testing the Peculiar Velocity Field predicted from Redshift Surveys
The reconstruction of the peculiar velocity field from the 1.936~Jy iras selected sample of galaxies is compared to a similar reconstruction from an optically selected sample. A general method for combining different samples to reconstruct a self-consistent density and peculiar velocity field is presented. The method i...
1994-01-28
2015-06-24
[ "astro-ph" ]
Wolfram Freudling, Luiz Nicolaci da Costa, Paulo S. Pellegrini
astro-ph/9401047
The Statistics of Gamma Ray Burst Lensing
Possibly the only unambiguous verification that gamma-ray bursts (GRBs) are at cosmological distances would be the observation of multiple images of a gravitationally lensed burst. Each images would arrive at a different time, but exhibit identical light curves. We improve upon previous calculations of GRB lensing by u...
1994-01-27
2009-10-22
[ "astro-ph" ]
S.A. Grossman and M.A. Nowak