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astro-ph/9412016
A Supergiant Supernova-Blown Bubble in the Spiral Galaxy NGC 1620
We present UBR and H$\alpha$ imaging of NGC 1620, a highly inclined spiral galaxy that contains a large scale, arc-like feature of radius 3 kpc in its outer disk at a distance of $\sim$ 11 kpc from the center. What is unusual about this arc-like feature is its stellar nature and the presence of a luminous star cluster ...
1994-12-06
2009-10-22
[ "astro-ph" ]
J. Patricia Vader and Brian Chaboyer
astro-ph/9412014
Cluster Alignments in the Edinburgh/Milano Cluster Redshift Survey
We present here the results of a statistical search for cluster alignments using the Edinburgh/Milano cluster redshift survey. This survey is a unique cluster database which has been objectively constructed to help minimise the systematic biases associated with previous optical cluster catalogues. We find some evidence...
1994-12-05
2015-06-24
[ "astro-ph" ]
D.R.Martin, R.C.Nichol, C.A.Collins, S.A.Lumsden and L.Guzzo
astro-ph/9412012
Cosmological Inflation, Microwave Background Anisotropies and Large Scale Structure of the Universe
Cosmological inflation provides the simplest and most promising mechanism for generating fluctuations for structure formation. Using powerful Hamilton-Jacobi methods, I will describe (1) how to compute density fluctuations and cosmic microwave anisotropies arising from inflation, and (2) improvements of the Zel'dovich ...
1994-12-05
2009-09-25
[ "astro-ph", "gr-qc", "hep-ph" ]
D. S. Salopek
astro-ph/9412011
Another Flattened Dark Halo: Plar Ring Galaxy A0136-0801
Knowledge of the shape of dark matter halos is critical to our understanding of galaxy formation, dynamics, and of the nature of dark matter itself. Polar ring galaxies (PRGs) --- early-type galaxies defined by their outer rings of gas, dust and stars on orbits nearly perpendicular to those of the central host --- prov...
1994-12-05
2009-10-22
[ "astro-ph" ]
Penny D. Sackett and Richard W. Pogge
astro-ph/9412013
Is Compton scattering in strong magnetic fields really infrared divergent?
The infrared behavior of QED changes drastically in the presence of a strong magnetic field: the electron self-energy and the vertex function are infrared {\em finite}, in contrast with field-free QED, while new infrared divergences appear that are absent in free space. One famous example of the latter is the infrared ...
1994-12-05
2009-10-22
[ "astro-ph", "hep-ph" ]
M. Kachelriess, D. Berg, and G. Wunner
astro-ph/9412010
Intergalactic Matter and Cocoons of Radio Galaxies
The cocoons surrounding powerful radio sources can be extensive if the jet that feeds the cocoon is light and supersonic. They have been shown to remain overpressured with respect to the ambient medium for most of the life time of the sources. The observed lobes of the radio sources form parts of these extensive cocoon...
1994-12-03
2015-06-24
[ "astro-ph" ]
Biman B. Nath
astro-ph/9412009
Probing the Galactic Dark Matter Mass Funtion Using Microlensing and Direct Searches
If compact baryonic objects contribute significantly to the dark matter in our Galaxy, their mass function will present vital clues for galaxy formation theories and star formation processes in the early Universe. Here we discuss what one might expect to learn about the mass function of Galactic dark matter from microl...
1994-12-02
2008-11-26
[ "astro-ph" ]
E. J. Kerins and B. J. Carr
astro-ph/9412006
Optical and Infrared Observations of SGR 1806-20
The soft gamma-ray repeater (SGR) 1806$-$20 is associated with the center-brightened non-thermal nebula G~10.0$-$0.3, thought to be a plerion. As in other plerions, a steady \Xray\ source, AX~1805.7$-$2025, has been detected coincident with the peak of the nebular radio emission. Vasisht et al.\ have shown that the rad...
1994-12-02
2009-10-22
[ "astro-ph" ]
S. R. Kulkarni, K. Matthews, G. Neugebauer, I. N. Reid, M. H. van Kerkwijk, G. Vasisht (Palomar Observatory, Caltech)
astro-ph/9412008
Maps of the Molecular Emission Around 18 Evolved Stars
We present maps at $20''$ resolution of the molecular emission around 18 evolved stars (14~asymptotic giant branch stars, one supergiant, two proto-planetary nebulae and one planetary nebula), mostly in the $^{12}$CO(3-2) line. Almost all molecular envelopes appear to be at least marginally resolved at this resolution....
1994-12-02
2009-10-22
[ "astro-ph" ]
K.Z. Stanek, G.R. Knapp, K. Young & T.G. Phillips
astro-ph/9412007
Microlensing, Newton-Einstein Gravity and Conformal Gravity
We discuss some implications of the current round of galactic dark matter searches for galactic rotation curve systematics and dynamics, and show that these new data do not invalidate the conformal gravity program of Mannheim and Kazanas which has been advanced as a candidate alternative to both the standard second ord...
1994-12-02
2009-10-22
[ "astro-ph" ]
Philip D. Mannheim (University of Connecticut)
astro-ph/9411117
Radio Monitoring and High Resolution Observations of the Soft Gamma Ray Repeater 1806-20. by Vasisht et al. Postscript file, 13 pages
We report the results of radio flux-monitoring and high resolution observations at 3.6 cm with the VLA, of the central condensation in G10.0-0.3, the radio nebula surrounding the soft gamma ray repeater (SGR) 1806-20. The quiescent X-ray source AX1805.7-2025 is coincident with the radio core suggesting that G10.0-0.3 i...
1994-12-01
2015-06-24
[ "astro-ph" ]
G. Vasisht, D. A. Frail, and S. R. Kulkarni
astro-ph/9412001
Nearby Galaxies and the Ginga X-ray Background
We present here the results of cross-correlating the X-ray background measured by Ginga in the 2-10 keV band with several catalogues of extragalactic objects. Positive signals with an amplitude of a few per cent have been found for some catalogues implying that some fraction of the X-ray background is produced either b...
1994-12-01
2015-06-24
[ "astro-ph" ]
F.J. Carrera, X. Barcons, J.A. Butcher, A.C. Fabian, O. Lahav, G.C. Stewart & R.S. Warwick
astro-ph/9412002
ROSAT Observations of Blazars from a Polarized Radio Selected Sample
We have observed with ROSAT six blazars from the sample of 31 polarized objects constructed by Impey and Tapia (1988). Results of the spectral analysis in the ROSAT band of three objects, PKS 0301-243, PKS 1055+018 and PG 1424+240 are presented here and compared with the three previously published objects. Using a simp...
1994-12-01
2009-10-22
[ "astro-ph" ]
L. Maraschi, G. Fossati, G. Tagliaferri and A. Treves
astro-ph/9412004
Subcluster Merger and Galaxy Infall in A2151
We have obtained a 12.5 ksec image of the Hercules Cluster, A2151, with the {\it ROSAT} PSPC. Comparison of the optical and X-ray data suggest the presence of at least three distinct subclusters in A2151. The brightest X-ray emission coincides with the highest-density peak in the galaxy distribution, and is bimodal. Th...
1994-12-01
2009-10-22
[ "astro-ph" ]
C.M. Bird (U. Kansas), D.S. Davis (GSFC/U. Maryland), T.C. Beers (Michigan State)
astro-ph/9411116
A Determination of the Thick Disk Chemical Abundance Distribution: Implications for Galaxy Evolution
We present a determination of the thick disk iron abundance distribution obtained from an in situ sample of F/G stars. These stars are faint, $15 \simlt V \simlt 18$, selected on the basis of color, being a subset of the larger survey of Gilmore and Wyse designed to determine the properties of the stellar populations s...
1994-12-01
2009-10-22
[ "astro-ph" ]
Gerard Gilmore (Institute of Astronomy, Cambridge), Rosemary F.G. Wyse (Center for Particle Astrophysics, University of California, Berkeley) and J. Bryn Jones (University of Wales, College of Cardiff)
astro-ph/9412003
Constraints on the topology of the universe from the 2-yr COBE data
The cosmic microwave background (CMB) is a unique probe of cosmological parameters and conditions. There is a connection between anisotropy in the CMB and the topology of the Universe. Adopting a universe with the topology of a 3-Torus, or a universe where only harmonics of the fundamental mode are allowed, and using 2...
1994-12-01
2009-10-22
[ "astro-ph" ]
Angelica de Oliveira-Costa, George F. Smoot
astro-ph/9412005
A brute force analysis of the COBE DMR data
More than a dozen papers analyzing the COBE data have now appeared. We review the different techniques and compare them to a ``brute force" likelihood analysis where we invert the full 4038 x 4038 Galaxy-cut pixel covariance matrix. This method is optimal in the sense of producing minimal error bars, and is a useful re...
1994-12-01
2008-11-26
[ "astro-ph" ]
Max Tegmark, Emory Bunn
astro-ph/9411115
Faint Field Galaxies: A Population of Intrinsically Faint Objects at Low Redshift?
To distinguish between the different models proposed to understand the excess of faint field counts over the predictions from non-evolving models, a number of redshift surveys have been undertaken. The answer has not arrived yet due to the high rate of incompleteness achieved. Un-identified galaxies have been shown to ...
1994-11-30
2007-05-23
[ "astro-ph" ]
Ana Campos (Instituto Astrofisica Andalucia Csic)
astro-ph/9411114
Recent Developments in Gravitational Microlensing and the Latest MACHO Results: Microlensing Towards the Galactic Bulge
We review recent gravitational microlensing results from the EROS, MACHO, and OGLE collaborations, and present some details of the very latest MACHO results toward the Galactic Bulge. The MACHO collaboration has now discovered in excess of 40 microlensing events toward the Galactic Bulge during the 1993 observing seaso...
1994-11-30
2009-10-22
[ "astro-ph" ]
D.P. Bennett, C. Alcock, R.A. Allsman, T.S. Axelrod, K.H. Cook, K.C. Freeman, K. Griest, 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/9411113
Optical variability of the supersoft source RX~J0019.8+2156
We present a 100 yr optical lightcurve of the recently discovered supersoft X-ray source RX~J0019.8+2156 as deduced from photographic plates of Harvard and Sonneberg Observatory. Apart from the periodic orbital variations two different timescales of optical variability are discovered. The timescales and amplitudes of t...
1994-11-29
2007-05-23
[ "astro-ph" ]
J. Greiner, W. Wenzel
astro-ph/9411112
Spatiotemporal complexity of the universe at subhorizon scales
This is a short note on the spatiotemporal complexity of the dynamical state(s) of the universe at subhorizon scales (up to 300 Mpc). There are reasons, based mainly on infrared radiative divergences, to believe that one can encounter a flicker noise in the time domain, while in the space domain, the scaling laws are r...
1994-11-29
2009-10-22
[ "astro-ph", "gr-qc" ]
H.C. Rosu
astro-ph/9411111
The Cosmic Microwave Background Dipole as a Cosmological Effect
A conventional explanation of the dipole anisotropy of the cosmic microwave background (CMB) radiation is in terms of the Doppler effect: our galaxy is moving with respect to CMB frame with $ \sim 600 ~ km ~ s^{-1} $. However, as the deep redshift surveys fail to reveal a convergence of the large scale flow to zero at ...
1994-11-29
2007-05-23
[ "astro-ph" ]
M. Jaroszynski (Warsaw University Observatory, Princeton University Observatory) and B. Paczynski(Princeton University Observatory)
astro-ph/9411110
Millimeter Observations of a Complete Sample of IRAS Galaxies: Dust Emission and Absorption in Spirals
We report on observations performed at 1.25 $mm$ of a southern galaxy sample, selected from the IRAS PSC and complete to $S_{60}=2 Jy$. We detected 18 sources and set significant limits on 10 further objects. We use these data to discuss the spatial distribution of cold dust, the broad-band far-IR/mm spectra, the overa...
1994-11-29
2009-10-22
[ "astro-ph" ]
A. Franceschini and P. Andreani (Osservatorio Astronomico - Padova)
astro-ph/9411109
RORF - a Radio Optical Reference Frame
The radio observations are based on dual frequency Mark--III VLBI data from 1979 until the end of 1993. Currently 436 sources define the celestial inertial frame. A comparison to the JPL94R01 catalog is made. Position vs. time plots of selected sources show significant apparent non linear proper motions. The status of ...
1994-11-29
2007-05-23
[ "astro-ph" ]
N.Zacharias, A.L.Fey, J.L.Russell and K.J.Johnston
astro-ph/9411106
Unified schemes for active galaxies: a clue from the missing Fanaroff-Riley type I quasar population
We link the lack of FR I type structure among quasars to the void of radio loud quasars below a critical disk luminosity of ~10^46 erg/sec in the PG sample. We argue that the opening angle of the obscuring torus in radio loud quasars depends on the power of the central engine, approaching the jet's beaming angle near t...
1994-11-28
2007-05-23
[ "astro-ph" ]
Heino Falcke, Gopal-Krishna, Peter L. Biermann
astro-ph/9411108
Chemical Evolution of Irregular and Blue Compact Galaxies
We discuss the chemical evolution of metal poor galaxies and conclude that their oxygen deficiency is not due to: the production of black holes by massive stars or a varying slope of the Initial Mass Function, IMF, at the high-mass end. A varying IMF at the low-mass end alone or in combination with: (a) an outflow of o...
1994-11-28
2009-10-22
[ "astro-ph" ]
L. Carigi (CIDA, Venezuela), P. Colin, M. Peimbert, and A. Sarmiento (IAUNAM, Mexico)
astro-ph/9411107
Temperature-Polarization Correlations from Tensor Fluctuations
We study the polarization-temperature correlations on the cosmic microwave sky resulting from an initial scale invariant spectrum of tensor (gravity wave) fluctuations, such as those which might arise during inflation. The correlation function has the opposite sign to that for scalar fluctuations on large scales, raisi...
1994-11-28
2010-12-13
[ "astro-ph", "hep-ph" ]
R.G. Crittenden, D. Coulson and N.G. Turok
astro-ph/9411105
Halo/Thick Disk CVs and the Cosmic X-Ray Background
In a recent study (Maoz and Grindlay 1995) we have found that a number of previously recognized anomalies in the diffuse x-ray background at soft energies (\sim 0.5-2 keV) can be understood if about 20-30% of the diffuse flux arises from a population of low luminosity sources in a thick disk or flattened halo distribut...
1994-11-27
2007-05-23
[ "astro-ph" ]
Jonathan E. Grindlay and Eyal Maoz
astro-ph/9411104
False Vacuum Inflation with a Quartic Potential
We consider a variant of Hybrid Inflation, where inflation is driven by two interacting scalar fields, one of which has a `Mexican hat' potential and the other a quartic potential. Given the appropriate initial conditions one of the fields can be trapped in a false vacuum state, supported by couplings to the other fiel...
1994-11-25
2016-08-24
[ "astro-ph" ]
David Roberts, Andrew R Liddle and David H Lyth
astro-ph/9411102
Gamma Ray Bursts, Neutron Star Quakes, and the Casimir Effect
We propose that the dynamic Casimir effect is a mechanism that converts the energy of neutron starquakes into $\gamma$--rays. This mechanism efficiently produces photons from electromagnetic Casimir energy released by the rapid motion of a dielectric medium into a vacuum. Estimates based on the cutoff energy of the gam...
1994-11-25
2007-05-23
[ "astro-ph", "hep-ph", "hep-th" ]
C. Carlson, T. Goldman and J. Perez-Mercader
astro-ph/9411103
The Morphological Evolution of Field Galaxies
I review two observational programs which, together, promise to unravel the detailed astrophysical evolution of normal field galaxies over the last 5-7 Gyr. Systematic ground-based spectroscopy of faint galaxies have revealed an increasing faint end slope for the luminosity function with redshift. The trend is stronges...
1994-11-25
2007-05-23
[ "astro-ph" ]
Richard S Ellis (Institute of Astronomy, Cambridge, UK)
astro-ph/9411101
Are Spiral Disks Really Opaque ?
We compare the ultra-violet, optical, and far-infrared emission for a sample of 135 spiral galaxies in order to address the widely debated problem concerning the opacity of spiral disks. We find that the re-radiation of the dust, estimated from the far-infrared emission, is on average only 31$\pm 1$ percent of the bolo...
1994-11-24
2007-05-23
[ "astro-ph" ]
C. Xu and V. Buat
astro-ph/9411099
Screening of Nuclear Reactions in the Sun and Solar Neutrinos
We quantitatively determine the effect and the uncertainty on solar neutrino production arising from the screening process. We present predictions for the solar neutrino fluxes and signals obtained with different screening models available in the literature and by using our stellar evolution code. We explain these nume...
1994-11-24
2009-09-25
[ "astro-ph" ]
B.Ricci, S. Degl'Innocenti and G. Fiorentini
astro-ph/9411100
The jet-disk symbiosis. II. Interpreting the Radio/UV correlations in quasars
We investigate the correlation between the accretion disk (UV) luminosity and the radio core emission of a quasar sample. In a radio/$L_{\rm disk}$ plot we find the quasars to be separated into four classes: core dominated quasars (CDQ), lobe dominated quasars (LDQ), radio-intermediate quasars (RIQ) and radio weak quas...
1994-11-24
2011-05-23
[ "astro-ph" ]
Heino Falcke, Matthew A. Malkan and Peter L. Biermann
astro-ph/9411097
Comparison of the COBE DMR and Tenerife Data
We have compared the Tenerife data with the {\it COBE} DMR two-year data in the declination +40\deg region of the sky observed by the Tenerife experiment. Using the Galactic plane signal at $\sim 30$ GHz, we show that the two data sets are cross-calibrated to within 5%. The high Galactic latitude data were investigated...
1994-11-23
2009-10-22
[ "astro-ph" ]
C. H. Lineweaver, S. Hancock, G. F. Smoot, A. N. Lasenby, R. D. Davies, A. J. Banday, C. M. Gutierrez de la Cruz, R. A. Watson, R. Rebolo
astro-ph/9411096
The jet-disk symbiosis. I. Radio to X-ray emission models for quasars
Starting from the assumption that radio jets and accretion disks are symbiotic features present in radio loud and radio quiet quasars we scale the bulk power of radio jets with the accretion power by adding mass- and energy conservation of the whole jet-disk system to the standard Blandford \& K\"onigl theory for compa...
1994-11-23
2011-05-23
[ "astro-ph" ]
Heino Falcke and Peter L. Biermann
astro-ph/9411098
Structure Formation with Decaying Neutrinos
We consider the effects of a massive, unstable neutrino on the evolution of large--scale structure and anisotropies in the cosmic microwave background. Comparison with large--scale structure data allows us to rule out a wide range of masses and lifetimes for such neutrinos. We also define a range of masses and lifetime...
1994-11-23
2008-11-26
[ "astro-ph" ]
M.White, G.Gelmini & J.Silk
astro-ph/9411089
Extragalactic Large-Scale Structures behind the Southern Milky Way. - I. Redshifts Obtained at the SAAO in the Hydra/Antlia Extension
Spectroscopic observations have been carried out for galaxies in the Milky Way with the 1.9 m telescope of the South African Astronomical Observatory (SAAO). The galaxies were selected from a deep optical galaxy search covering 266<l<296 |b|<10deg. This is in the extension of the Hydra and Antlia clusters and in the ap...
1994-11-22
2007-05-23
[ "astro-ph" ]
Renee C. Kraan-Korteweg (Kapteyn Institute, Groningen), Tony P. Fairall (UCT, Cape Town), Chantal Balkowksi (Observatoire de Meudon)
astro-ph/9411092
The Optical Gravitational Lensing Experiment. Follow-Up Observations of the Macho Microlensing Event in the Galactic Bulge
We present follow-up observations of a gravitational microlensing candidate found by the MACHO collaboration in the Galactic bulge. The photometric data cover a period near the maximum of the event and may be used to construct complete light curve. The position of the lensed star in the color magnitude diagram suggests...
1994-11-22
2009-09-25
[ "astro-ph" ]
M. Szymanski, A. Udalski, J. Kaluzny, M. Kubiak, W. Krzeminski and M. Mateo
astro-ph/9411095
How Do the Stellar Disc and Thick Disc Stop ?
As part of a stellar population sampling program, a series of photometric probes at various field sizes and depths have been obtained in a low extinction window in the galactic anticentre direction. Very deep CCD frames probe the most external parts of the disc, providing strong evidence that the galactic density scale...
1994-11-22
2007-05-23
[ "astro-ph" ]
Annie C. Robin, Michel Creze, Vijay Mohan
astro-ph/9411091
Hydrodynamics of the Cosmological Quark-Hadron Transition in the Presence of Long-Range Energy and Momentum Transfer
Two previous papers in this series have presented a study of the growth of hadronic bubbles during the cosmological Quark--Hadron transition, treating the material within each phase as a single perfect fluid. Here, we extend the analysis to include the effects of long-range energy and momentum transfer by weakly and el...
1994-11-22
2009-10-22
[ "astro-ph", "gr-qc", "hep-ph" ]
J.C. Miller and L. Rezzolla
astro-ph/9411094
Molecular Photodissociation in the Neutral Envelopesof Planetary Nebulae
The dissociation and subsequent ionisation of molecular material in a detached, spherically symmetric stellar wind is modelled as a star evolves from the post-asymptotic giant branch phase to a planetary nebula (i.e. from a stellar effective temperature of Teff=6000K to Teff=33000K). The model is compared to the observ...
1994-11-22
2015-06-24
[ "astro-ph" ]
G.T.Gussie, A.R.Taylor, P.E.Dewdney, and R.S.Roger
astro-ph/9411093
HI and CO Observations of Circumnebular Envelopes of Planetary Nebulae
21cm spectral-line and continuum observations of ten compact planetary nebulae have been made with the Very Large Array. Circumnebular atomic hydrogen is identified in the planetary nebulae SwSt1, M3-35, and possibly in Hu2-1. The possibility of an inverse correlation between the optical depth of circumnebular atomic h...
1994-11-22
2015-06-24
[ "astro-ph" ]
G. T. Gussie and A. R. Taylor
astro-ph/9411090
A $BVI$ Photometric Study of the Near-Galactic Center Globular Cluster NGC 6517 (C1759-089)
We present the results of a $BVI$ photometric study of the globular cluster NGC 6517 using CCD images obtained at the prime focus of the CFHT. From the resultant color-magnitude diagram, we infer that the cluster is differentially reddened and develop a method for determining the amplitude of this effect, which amounts...
1994-11-22
2009-10-22
[ "astro-ph" ]
JJ Kavelaars, David A. Hanes, Terry J. Bridges and William E. Harris
astro-ph/9411084
Radio Supernovae as Tev Gamma-Ray Sources
When applied to the blast wave formed by the explosion of a massive star as a supernova (SN), the theory of diffusive particle acceleration at shock fronts predicts a very high energy density in cosmic rays. Almost immediately after particles begin to be injected into the process, the cosmic ray pressure rises until co...
1994-11-21
2011-05-23
[ "astro-ph" ]
J.G. Kirk, P. Duffy and Lewis Ball
astro-ph/9411083
Multicolor surface photometry of brightest cluster galaxies: II. Enlarging the sample and improving the analysis
Intrinsic color profiles of a sample of nine Brightest Cluster Galaxies (BCGs) are recovered from the observed color profiles by evaluating spurious gradients introduced by errors in the determination of the sky levels and by different seeing conditions between the observations. Isophote shapes and surface brightness p...
1994-11-21
2008-02-03
[ "astro-ph" ]
S. Andreon, B.Garilli and D. Maccagni
astro-ph/9411088
The Vertical Distribution and Kinematics of HI and Mass Models of the Galactic Disk
We present full modeling of tangent point emission of HI as seen in the 21 cm transition in the inner Galaxy ($R \simeq 3-8 \kpc$). The model used takes into account emission from a large path length along the line of sight, corresponding to an interval ($\Delta R$) of typically $\le 1 \kpc$ in galactic radius; and is ...
1994-11-21
2011-03-28
[ "astro-ph" ]
Sangeeta Malhotra
astro-ph/9411087
Complete Model of a Self-gravitating Cosmic String I. A New Class of Exact Solutions and Gravitational Lensing
We find solutions of Einstein's field equation for topologically stable strings associated with the breaking of a U(1) symmetry. Strings form in many GUTs and are expected whenever the homotopy group $\Pi_1(M_0)$ is non-trivial. The behavior of the fields making up the string is described by the Euler-Lagrange equation...
1994-11-21
2009-10-22
[ "astro-ph" ]
Charles C. Dyer and Francine R. Marleau (Department of Astronomy, University of Toronto, Canada)
astro-ph/9411085
Quasar Populations in a Cosmological Constant Dominated Flat Universe
Most physical properties derived for quasars, as single entities or as a population, depend upon the cosmology assumed. In this paper, we calculate the quasar luminosity function and some related quantities for a flat universe dominated by a cosmological constant $\Lambda$ ($\Lambda=0.9, \Omega=0.1$) and compare them w...
1994-11-21
2009-10-22
[ "astro-ph" ]
Sangeeta Malhotra and Edwin L Turner
astro-ph/9411086
The UV-Drag on Hadronic Hot Jets as the Origin of X-Ray Irradiation in AGN
Consequences of anisotropic cascade radiation in AGN are investigated. The anisotropic cascades are produced by protons accelerated in a nuclear jet. The protons are assumed to cool in the UV photon field of an accretion disk by photo-production of secondary particles. Most cascade photons are produced in the direction...
1994-11-21
2007-05-23
[ "astro-ph" ]
Karl Mannheim (Goettingen University Observatory)
astro-ph/9411082
Gravitational Lensing Limits on Cold Dark Matter and Its Variants
Standard $\Omega_0=1$ cold dark matter (CDM) needs $0.27 < \sigma_8 < 0.63$ ($2\sigma$) to fit the observed number of large separation lenses, and the constraint is nearly independent of $H_0=100h^{-1}\kms$ Mpc$^{-1}$. This range is strongly inconsistent with the COBE estimate of $\sigma_8=(2.8\pm0.2)h$. Tilting the pr...
1994-11-19
2009-10-22
[ "astro-ph" ]
Christopher S. Kochanek
astro-ph/9411076
ROSAT observations of the B2 radio galaxies 1615+35 and 1621+38: implications on the radio source confinement
We report X-ray observations of the radio galaxies B2 1615+35 (NGC 6109) and B2 1621+38 (NGC 6137), which belong to poor groups of galaxies and are characterized by a "head-tail" structure. We also analyze the X-ray behaviour of the radio galaxy NGC 6107, present within the field of view and showing a symmetric extende...
1994-11-18
2007-05-23
[ "astro-ph" ]
L.Feretti, R. Fanti, P. Parma, S. Massaglia, E. Trussoni, W. Brinkmann (IRA, Bologna - OA, Torino - MPE, Garching)
astro-ph/9411080
Spectral Classification of Galaxies
We investigate the integrated spectra of a sample of 24 normal galaxies. A principal component analysis suggests that most of the variance present in the spectra is due to the differences in morphology of the galaxies in the sample. We show that spectroscopic parameters extracted from the spectra, like the amplitude of...
1994-11-18
2009-10-22
[ "astro-ph" ]
Laerte Sodre Jr. and Hector Cuevas
astro-ph/9411077
Open clusters as tracers of the evolution of the Galaxy
Deep color-magnitude diagrams are presented for poorly known open clusters Cr 261, Be 18, Be 54, Tr 5 and BH176. All clusters are old objects with age\geq 4 Gyr. BH176 is either old open cluster or young globular cluster. Extremely red giants with V-I>3 were identified in the central parts of Cr 261, Be 54 and BH176. T...
1994-11-18
2007-05-23
[ "astro-ph" ]
Janusz Kaluzny, Wojtek Krzeminski & Beata Mazur
astro-ph/9411075
The Space Distribution of the Lyman Alpha Clouds in the Line of Sight to the Z=3.66 QSO 0055-269
The spectrum of the quasar Q0055-269 ($z=3.66$) has been observed at the resolution of 14 km s$^{-1}$ in the wavelength interval 4750--6300 \AA. We give a list of Lyman$-\alpha$ lines and metal-line systems for which column densities and Doppler widths have been derived by a fitting procedure. The statistical distribut...
1994-11-18
2015-06-24
[ "astro-ph" ]
S. Cristiani, S. D'Odorico, A. Fontana, E. Giallongo, S. Savaglio
astro-ph/9411074
A non-LTE study of Li I lines in AGB stars
We study the formation of Li lines in a case study of an S-type AGB star in the SMC. AGB stars may be important providers of $^7$Li to the interstellar medium. Abundance analysis of these stars is difficult due to the heavy molecular blanketing, uncertainties in the model atmospheres and possible departures from LTE in...
1994-11-18
2007-05-23
[ "astro-ph" ]
Dan Kiselman (NORDITA, Copenhagen) and Bertrand Plez (Niels Bohr Institute, Copenhagen)
astro-ph/9411081
The formation of close binary systems
A viable solution to the origin of close binary systems, unaccounted for in recent theories, is presented. Fragmentation, occurring at the end of the secondary collapse phase (during which molecular hydrogen is dissociating), can form binary systems with separations less than 1 au. Two fragmentation modes are found to ...
1994-11-18
2015-06-24
[ "astro-ph" ]
Ian A. Bonnell and Matthew R. Bate
astro-ph/9411079
The Cluster Distribution as a Test for Dark Matter Models. I: Clustering Properties
We present extended simulations of the distribution of galaxy clusters in different dark matter models, using an optimized version of the Zel'dovich approximation. Six different dark matter models are studied: Standard CDM, Open CDM, Tilted CDM, Cold + Hot DM, low-density CDM with cosmological constant, and low Hubble ...
1994-11-18
2009-10-22
[ "astro-ph" ]
S. Borgani, M. Plionis, P. Coles, L. Moscardini
astro-ph/9411078
The Optical Gravitational Lensing Experiment. Variable stars in the Sculptor dwarf speroidal galaxy
The central area of the Sculptor dwarf galaxy was surveyed for variable stars as a side-program of the OGLE project. Light curves in the V band were obtained for 226 RR Lyr stars and for 3 anomalous cepheids. One previously unknown anomalous cepheid was identified. We discovered also two variables located at the tip of...
1994-11-18
2007-05-23
[ "astro-ph" ]
J. Kaluzny, M. Kubiak, M. Szymanski, A. Udalski, W. Krzeminski & M. Mateo
astro-ph/9411070
Approaches to Automated Morphological Classification of Galaxies
There is an obvious need for automated classification of galaxies, as the number of observed galaxies increases very fast. We examine several approaches to this problem, utilising {\em Artificial Neural Networks} (ANNs). We quote results from a recent study which show that ANNs can classsify galaxies morphologically as...
1994-11-17
2009-10-22
[ "astro-ph" ]
Avi Naim
astro-ph/9411071
Artificial Neural Networks as Non-Linear Extensions of Statistical Methods in Astronomy
We attempt to de-mistify Artificial Neural Networks (ANNs) by considering special cases which are related to other statistical methods common in Astronomy and other fields. In particular we show how ANNs generalise Bayesian methods, multi-parameter fitting, Principal Component Analysis (PCA), Wiener filtering and regul...
1994-11-17
2009-10-22
[ "astro-ph" ]
Ofer Lahav
astro-ph/9411068
Astrometric Tests of Galactic Evolution
There are many fundamental aspects of Galactic structure and evolution which can be studied best or exclusively with high quality three dimensional kinematics. Amongst these we note as examples determination of the orientation of the stellar velocity ellipsoid, and the detection of structure in velocity-position phase ...
1994-11-17
2007-05-23
[ "astro-ph" ]
Gerard Gilmore (Institute of Astronomy, Cambridge, UK)
astro-ph/9411069
Evolution of the Galactic Halo and Disk
Correlations between stellar kinematics and chemical abundances are fossil evidence for evolutionary connections between Galactic structural components. Extensive stellar surveys show that the only tolerably clear distinction between galactic components appears in the distributions of specific angular momentum. Here th...
1994-11-17
2009-10-22
[ "astro-ph" ]
Gerard Gilmore (Institute of Astronomy, Cambridge, UK)
astro-ph/9411073
Microlensing and Halo Cold Dark Matter
We discuss the implications of the more than 50 microlensing events seen by the EROS, MACHO, and OGLE collaborations for the composition of the halo of our galaxy. The event rates indicate that the halo mass fraction in MACHO's is less than 30\%, consistent with expectations for a universe whose primary component is co...
1994-11-17
2009-10-22
[ "astro-ph", "hep-ph" ]
Evalyn I. Gates, Geza Gyuk, and Michael S. Turner
astro-ph/9411072
Protogalactic evolution and magnetic fields
We show that the relatively strong magnetic fields ($\ge 1 \mu$G) in high redshift objects can be explained by the combined action of an evolving protogalactic fluctuation and electrodynamic processes providing the magnetic seed fields. Three different seed field mechanisms are reviewed and incorporated into a spherica...
1994-11-17
2007-05-23
[ "astro-ph" ]
Harald Lesch and Masashi Chiba
astro-ph/9411060
Advection-Dominated Accretion Model for Sagittarius A$^*$: Evidence for a $10^6\msun$ Black Hole at the Galactic Center
The enigmatic radio source Sagittarius A* at the centre of our Galaxy appears to be a low-luminosity version of active galactic nuclei in other galaxies. By analogy with active galactic nuclei models, it has been proposed that Sgr A* may be a massive accreting black holes. The black hole hypothesis is, however, problem...
1994-11-16
2007-05-23
[ "astro-ph" ]
Ramesh Narayan, Insu Yi, and Rohan Mahadevan
astro-ph/9411066
Eulerian Perturbation Theory in Non-Flat Universes: Second-Order Approximation
The problem of solving perturbatively the equations describing the evolution of self-gravitating collisionless matter in an expanding universe considerably simplifies when directly formulated in terms of the gravitational and velocity potentials: the problem can be solved {\it exactly}, rather than approximately, even ...
1994-11-16
2015-06-24
[ "astro-ph" ]
Paolo Catelan, Francesco Lucchin, Sabino Matarrese & Lauro Moscardini
astro-ph/9411067
Dwarf Spheroidal Galaxies : Keystones of Galaxy Evolution
Dwarf spheroidal galaxies are the most insignificant extragalactic stellar systems in terms of their visibility, but potentially very significant in terms of their role in the formation and evolution of much more luminous galaxies. We discuss the present observational data and their implications for theories of the for...
1994-11-16
2015-06-24
[ "astro-ph" ]
John S. Gallagher III and Rosemary F.G. Wyse
astro-ph/9411062
Resurrection of Traditional Luminosity Evolution Models to Explain Faint Field Galaxies
We explore the nature of the evolution of faint field galaxies by assuming that the local luminosity function is not well defined. We use a non-negative least squares technique to derive a near optimal set of local luminosity functions for different spectral types of galaxies by fitting to the observed optical and near...
1994-11-16
2009-10-22
[ "astro-ph" ]
Caryl Gronwall and David C. Koo
astro-ph/9411065
WHAT IS SGR A*? The Starved Black Hole in the Center of the Milky Way
Sgr A* is the unique 1 Jy flat spectrum radio point source located at the dynamical center of the Galaxy and in the very center of the central star cluster. Due to its unusual appearance it has long been speculated that this source is powered by a supermassive black hole. The enormous increase in observational data obt...
1994-11-16
2007-05-23
[ "astro-ph", "gr-qc" ]
Heino Falcke
astro-ph/9411064
Radio pulsar and accretion regimes of rapidly rotating magnetic neutron stars in early-type eccentric binaries
Rapidly rotating magnetic neutron stars in eccentric binary systems containing an early type star provide a unique opportunity to investigate the interplay between radio pulsar, stellar wind and accretion phenomena. We summarise the radio pulsar-dominated and the accretion-dominated regimes, discussing how the transiti...
1994-11-16
2007-05-23
[ "astro-ph" ]
S. Campana, L. Stella, S. Mereghetti & M. Colpi
astro-ph/9411061
The MACHO Project LMC Variable Star Inventory: I. Beat Cepheids - Conclusive Evidence for the Excitation of the Second Overtone in Classical Cepheids
We report the discovery of 45 beat Cepheids in the Large Magellanic Cloud (LMC) using the MACHO Project photometry database. The variables which are pulsating simultaneously in two radial modes are shown to break cleanly into two period-ratio groups, providing the first unambiguous evidence that the second overtone is ...
1994-11-16
2010-03-19
[ "astro-ph" ]
C. Alcock, R.A. Allsman, T.S. Axelrod, D.P. Bennett, K.H. Cook, K.C. Freeman, K. Griest, S.L. Marshall, B.A. Peterson, M.R. Pratt, P.J. Quinn, J. Reimann, A.W. Rodgers, C.W. Stubbs, W. Sutherland, and D.L. Welch (The MACHO Collaboration)
astro-ph/9411063
ROSAT PSPC Observations of the Seyfert 1 Galaxies Ark 564, NGC 985, Kaz 163, MRK 79 and RX J 2256.6+0525
We present spatial, temporal and spectral analyses of ROSAT Position Sensitive Proportional Counter (PSPC) observations of the Seyfert 1 galaxies Ark 564, NGC 985, Kaz 163, Mrk 79 and RX J2256.6+0525. Ark 564 is a powerful narrow-line Seyfert 1 with strong Fe II emission. Several similar narrow-line Seyfert 1 galaxies ...
1994-11-16
2015-06-24
[ "astro-ph" ]
W.N. Brandt, A.C. Fabian, K. Nandra, C.S. Reynolds, W. Brinkmann
astro-ph/9411059
Advection-Dominated Accretion: Underfed Black Holes and Neutron Stars
We describe new optically thin solutions for rotating accretion flows around black holes and neutron stars. These solutions are advection dominated, so that most of the viscously dissipated energy is advected radially with the flow. We model the accreting gas as a two temperature plasma and include cooling by bremsstra...
1994-11-15
2009-10-22
[ "astro-ph" ]
Ramesh Narayan and Insu Yi
astro-ph/9411055
Statistical properties of the faint early-type galaxies sample: possible effects of evolution
Early-type galaxies from CfA catalogue were assotiated with IRAS FSC sources. In given sample IR and optical properties were used to obtain some classification of these objects. The existance of significant classes can be evidence of presence one main type of the dust in each galaxy. Physical interpretation of obtained...
1994-11-15
2007-05-23
[ "astro-ph" ]
I.A.Trifalenkov
astro-ph/9411056
General Relativistic Hydrodynamics with a Roe solver
We present a numerical method to solve the equations of general relativistic hydrodynamics in a given external gravitational field. The method is based on a generalization of Roe's approximate Riemann solver for the non relativistic Euler equations in Cartesian coordinates. The new method is applied to a set of standar...
1994-11-15
2007-05-23
[ "astro-ph" ]
Frits Eulderink and Garrelt Mellema
astro-ph/9411057
Chemical Evolution of the Galaxy
Standard models for the chemical evolution of the Galaxy are reviewed with particular emphasis on the history of the abundance gradients in the disk. The effects on the disk structure and metallicity of gas accretion are discussed, showing that a significant fraction of the current disk mass has been accreted in the la...
1994-11-15
2007-05-23
[ "astro-ph" ]
M.Tosi
astro-ph/9411058
Advection-Dominated Accretion: Self-Similarity and Bipolar Outflows
We consider axisymmetric viscous accretion flows where a fraction f of the viscously dissipated energy is advected with the accreting gas as stored entropy and a fraction 1-f is radiated. When f is small (i.e. very little advection), our solutions resemble standard thin disks in many respects except that they have a ho...
1994-11-15
2009-10-22
[ "astro-ph" ]
Ramesh Narayan and Insu Yi
astro-ph/9411051
Spectroscopic Studies of the Two Eros Candidate Microlensed Stars
Low resolution spectroscopy, and UBVRI photometry, have been obtained for the two EROS microlensing candidates. Radial velocities indicate that both stars are members of the Large Magellanic Cloud. The spectrum and the colours of EROS1, the first candidate, reveal that it is a moderately reddened main-sequence B star w...
1994-11-14
2007-05-23
[ "astro-ph" ]
J.P. Beaulieu, R. Ferlet, Ph. Grison, A. Vidal-Madjar, J.P. Kneib, E. Maurice, L. Prevot, C. Gry, J. Guibert, O. Moreau, F. Tajahmady, E. Aubourg, P. Bareyre, S. Brehin, M. Gros, M. Lachieze-Rey, B. Laurent, E. Lesquoy, C. Magneville, A. Milsztajn, L. Moscoso, F. Queinnec, J. Rich, M. Spiro, L. Vigroux, S. Zylb...
astro-ph/9411054
Probing Early Clustering with Lyman-Alpha Absorption Lines Beyond the Quasar Redshift
Groups and clusters of galaxies hosting a quasar can be found through the detection of Lyman-alpha absorption lines beyond the quasar redshift. The effect occurs whenever the distortion to the redshift distribution of Lyman-alpha clouds induced by the cluster potential extends beyond the proximity effect of the quasar....
1994-11-14
2009-10-22
[ "astro-ph" ]
Abraham Loeb and Daniel J. Eisenstein (Harvard Univ.)
astro-ph/9411052
Using X-rays to Determine Which Compact Groups are Illusory
If the large-scale galaxy distribution is filamentary, as suggested by some observations and recent hydrodynamical simulations, then lengthwise views of filaments will apparently produce compact groups (CGs) that are in reality stretched out along the line of sight. This possibility has been advocated recently by Hernq...
1994-11-14
2009-10-22
[ "astro-ph" ]
Jeremiah P. Ostriker, Lori M. Lubin, and Lars Hernquist
astro-ph/9411053
Platelet Collapse Model of Pulsar Glitches
A platelet collapse model of starquakes is introduced. It displays self-organized criticality with a robust power-law behavior. The simulations indicate a near-constant exponent, whenever scaling is present.
1994-11-14
2010-12-17
[ "astro-ph" ]
P.D. Morley and Ivan Schmidt
astro-ph/9411050
Continuum Power Spectrum Components in X-Ray Sources: Detailed Modelling and Search for Coherent Periodicities
This paper summarises two recently developed techniques in power spectral analysis and their application to a sample of X-ray light curves of accreting collapsed objects in active galactic nuclei and X-ray binaries. The first technique is designed to carry out detailed model fitting of continuum power spectrum componen...
1994-11-13
2007-05-23
[ "astro-ph" ]
L. Stella, E. Arlandi, G. Tagliaferri and G.L. Israel
astro-ph/9411046
Homogeneous Velocity-Distance Data for Peculiar Velocity Analysis. I. Calibration of Cluster Samples
We have combined five Tully-Fisher (TF) redshift-distance samples for peculiar velocity analysis: the cluster data of Han, Mould and coworkers (1991-93, HM) and Willick (1991, W91CL), and the field data of Aaronson et al. (1992), Willick (1991), Courteau & Faber (1992), and Mathewson et al. (1992), totaling over 3000 s...
1994-11-11
2009-10-22
[ "astro-ph" ]
Jeffrey A. Willick, Stephane Courteau, Sandra M. Faber, David Burstein, and Avishai Dekel
astro-ph/9411045
Substructures of Clusters and Cosmological Models
We investigate, using high resolution N-body simulations, the density profiles and the morphologies of galaxy clusters in three models of structure formation. We show that these properties are closely related to the occurrence of a significant merging event to a cluster in the recent past. The three models are: (1) the...
1994-11-11
2007-05-23
[ "astro-ph" ]
Y. P. Jing, H. J. Mo, G. Boerner, L. Z. Fang
astro-ph/9411048
The lens parallax method: determining the redshifts of the faint blue galaxies through gravitational lensing
We propose a new technique, which we call the lens parallax method, to determine simultaneously the redshift distribution of the faint blue galaxies and the mass distribution of foreground clusters of galaxies. The method is based on gravitational lensing and uses the fact that the mean angular size of the faint blue g...
1994-11-11
2007-05-23
[ "astro-ph" ]
Ramesh Narayan and Matthias Bartelmann
astro-ph/9411049
Modern Cosmology and Structure Formation
An introduction to modern cosmology is given, focusing on theories for the origin of structure in the Universe. After a brief review of the theory of growth of cosmological perturbations and a summary of some important observational results, most of the article is devoted to discussions of the inflationary Universe sce...
1994-11-11
2008-04-11
[ "astro-ph", "hep-ph" ]
Robert H. Brandenberger (Brown University)
astro-ph/9411047
Influence of Strings with Axionic Content on the Polarization of Extragalactic Sources
It is shown that the axion concentrated in electroweak strings which are consequently stabilized may produce a rotation of the polarization angle of radiation from extragalactic sources larger than that caused by a background field, and that axionic walls attached to global strings have an effect which depends on the f...
1994-11-11
2011-05-23
[ "astro-ph", "hep-ph" ]
Luis Masperi and Sandra Savaglio
astro-ph/9411044
Spectral Classification of Galaxies: An Orthogonal Approach
Classification of galaxy spectral energy distributions in terms of orthogonal basis functions provides an objective means of estimating the number of significant spectral components that comprise a particular galaxy type. We apply the Karhunen-Lo\`{e}ve transform to derive a spectral eigensystem from a sample of ten ga...
1994-11-10
2011-05-05
[ "astro-ph" ]
A.J. Connolly, A.S. Szalay (Johns Hopkins University), M.A. Bershady (Penn State University), A.L. Kinney and D. Calzetti (STSci)
astro-ph/9411040
Collapse and Fragmentation of Cylindrical Magnetized Clouds. II. Simulation with Nested Grid Scheme
Fragmentation process in a cylindrical magnetized cloud is studied with the nested grid method. The nested grid scheme use 15 levels of grids with different spatial resolution overlaid subsequently, which enables us to trace the evolution from the molecular cloud density $\sim 100 {\rm cm}^{-3}$ to that of the protoste...
1994-11-10
2015-06-24
[ "astro-ph" ]
Kohji Tomisaka (Niigata University)
astro-ph/9411042
Velocity Profile of the Ionized Disk and the Mass of the Black Hole in M87
We present a theoretical model for the ionized disk in M87 which includes spiral shock waves. The line emission profiles computed from this model at various positions on the disk are found to be in agreement with the recent Hubble Space Telescope results. Based on this model, we find that the ionized disk comprises two...
1994-11-10
2009-10-22
[ "astro-ph" ]
Sandip K. Chakrabarti
astro-ph/9411041
Chemical evolution models with a new stellar nucleosynthesis
Numerical models for the chemical evolution of the Galaxy have been computed with the new stellar yields published by Maeder (1992). These metallicity dependent yields represent an important improvement in the chemical evolution of galaxies but there are still uncertainties in the stellar evolution which prevent comple...
1994-11-10
2015-06-24
[ "astro-ph" ]
A. Giovagnoli, M. Tosi
astro-ph/9411039
Angular Momemtum and Large-Scale Magnetic Field in Textures Seeded Models
We start by pedagigically reviewing the problem of large scale magnetic fields. We explain the acquisition of angular momentum in the general context of Dark Matter models and we use this result to derive a dynamical mechanism for magnetic field generation. This mechanism does not produce any magnetic field for standar...
1994-11-10
2016-08-30
[ "astro-ph" ]
Hugues Sicotte (Princeton University)
astro-ph/9411043
Gamma Ray Lines from the Orion Complex
We show that the 4.44 and 6.13 MeV line emission observed with COMPTEL from Orion is consistent with gamma ray spectra consisting of a mixture of narrow and broad lines or spectra containing only broad lines. We employed several accelerated particle compositions and showed that the current COMPTEL data in the 3--7 MeV ...
1994-11-10
2009-10-22
[ "astro-ph" ]
Reuven Ramaty, Benzion Kozlovsky, Richard E. Lingenfelter
astro-ph/9411038
The Particle- and Astro-Physics of Dark Matter
We review some recent determinations of the amount of dark matter on galactic, cluster, and large scales, noting some puzzles and their possible resolutions. We discuss the interpretation of big bang nucleosynthesis for dark matter, and then review the motivation for and basic physics of several dark matter candidates,...
1994-11-09
2007-05-23
[ "astro-ph", "hep-ph" ]
Kim Griest
astro-ph/9411037
Images of HCO+ (1-0) Emission in a Molecular Cloud near 1E1740.7-2942
We have observed the hard X-ray source 1E1740.7-2942 in the HCO+ (1-0) line using the Owens Valley millimeter interferometer. Previous single dish observations have found HCO+ emission coincident with the location of the radio continuum hot spots of the radio source associated with 1E1740.7-2942. Our higher resolution ...
1994-11-09
2009-10-22
[ "astro-ph" ]
J.A. Phillips (Owens Valley Radio Observatory) and T. Joseph W. Lazio (Cornell University)
astro-ph/9411036
Does a Non-Magnetic Solar Chromosphere Exist?
Enhanced chromospheric emission which corresponds to an outwardly increasing semiempirical temperature structure can be produced by wave motion without any increase in the mean gas temperture. Hence, the sun may not have a classical chromosphere in magnetic field free internetwork regions. Other significant differences...
1994-11-09
2009-10-22
[ "astro-ph" ]
Mats Carlsson and Robert F. Stein
astro-ph/9411032
Comparing Models of Rapidly Rotating Relativistic Stars Constructed by Two Numerical Methods
We present the first direct comparison of codes based on two different numerical methods for constructing rapidly rotating relativistic stars. A code based on the Komatsu-Eriguchi-Hachisu (KEH) method (Komatsu et al. 1989), written by Stergioulas, is compared to the Butterworth-Ipser code (BI), as modified by Friedman,...
1994-11-08
2010-04-06
[ "astro-ph", "gr-qc" ]
Nikolaos Stergioulas and John L. Friedman
astro-ph/9411033
Gravitational Lensing and the Mass Distribution of Clusters
We review and discuss information on the mass distribution of galaxy clusters obtained from gravitational lensing.
1994-11-08
2009-10-22
[ "astro-ph" ]
Matthias Bartelmann and Ramesh Narayan
astro-ph/9411034
Constraints on the Gamma-ray Burst Luminosity Function from PVO and BATSE
We examine the width of the gamma-ray burst luminosity function through the distribution of GRB peak fluxes as detected by the Pioneer Venus Orbiter (PVO) and the Burst and Transient Source Experiment (BATSE). The strength of the analysis is greatly enhanced by using a merged catalog of peak fluxes from both instrument...
1994-11-08
2016-08-30
[ "astro-ph" ]
Andrew Ulmer, Ralph A.M.J. Wijers, and Edward E. Fenimore