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A Subrelativistic Shock Model for the Radio Emission of SN 1998bw
(American Astronomical Society, 1999)
SN 1998bw is the most luminous radio supernova ever observed. Previous discussions argued that its exceptional radio luminosity, similar to 4 x 10(38) ergs s(-1), must originate from a highly relativistic shock that is ...
An analytical model for the triaxial collapse of cosmological perturbations
(American Astronomical Society, 1995)
We present an analytical model for the nonspherical collapse of overdense regions out of a Gaussian random field of initial cosmological perturbations. The collapsing region is treated as an ellipsoid of constant density, ...
Microlensing of Quasars by Stars in Their Damped Lyα Absorbers
(American Astronomical Society, 1997)
The damped Ly alpha absorbers (DLAs) in quasar spectra are believed to be the progenitors of present-day disk galaxies. We examine the probability for microlensing of background quasars by stars in their DLAs. Microlensing ...
Evidence from gravitational lensing for a nonthermal pressure support in the cluster of galaxies Abell 2218
(American Astronomical Society, 1994)
The central mass distribution of clusters of galaxies can be inferred from gravitationally lensed arcs with known redshifts. For the cluster Abell 2218, this method yields a core mass which is larger by a factor of 2.5 +/- ...
Identifying the Environment and Redshift of Gamma‐Ray Burst Afterglows from the Time Dependence of Their Absorption Spectra
(American Astronomical Society, 1998)
The discovery of gamma-ray burst (GRB) afterglows revealed a new class of variable sources at optical and radio wavelengths. At present, the environment and precise redshift of the detected afterglows are still unknown. ...
Probing the Mass Fraction of MACHOs in Extragalactic Halos
(American Astronomical Society, 1998)
Current microlensing searches calibrate the mass fraction of the Milky Way halo that is in the form of massive astrophysical compact halo objects (MACHOs). We show that surveys like the Sloan Digital Sky Survey (SDSS) can ...
Stable and Unstable Accretion Flows with Angular Momentum near a Point Mass
(American Astronomical Society, 1995)
The properties of axisymmetric accretion flows of cold adiabatic gas with zero total energy in the vicinity of a Newtonian point mass are characterized by a single dimensionless parameter, the thickness of incoming flow. ...
Direct Measurement of Cosmological Parameters from the Cosmic Deceleration of Extragalactic Objects
(American Astronomical Society, 1998)
The redshift of all cosmological sources drifts by a systematic velocity of order a few meters per second over a century as a result of the deceleration of the universe. The specific functional dependence of the predicted ...
Signatures of Intergalactic Dust from the First Supernovae
(American Astronomical Society, 1997)
We quantify the consequences of intergalactic dust produced by the first Type II supernovae in the universe. The fraction of gas converted into stars is calibrated based on the observed C/H ratio in the intergalactic medium ...
Effects of Disks on Gravitational Lensing by Spiral Galaxies
(American Astronomical Society, 1998)
Gravitational lensing of a quasar by a spiral galaxy should often be accompanied by damped Ly alpha absorption and dust extinction due to the intervening gaseous disk. In nearly edge-on configurations, the surface mass ...