Charles R. Evans

The tidal disruption of a star by a massive black hole

Results are reported from a three-dimensional numerical calculation of the tidal disruption of a low-mass main-sequence star on a parabolic orbit around a massive black hole (Mh = 10 to the 6th stellar mass). The postdisruption evolution is followed until hydrodynamic forces becomes negligible and the liberated gas becomes ballistic. Also given is the rate at which bound mass returns to pericenter after orbiting the hole once. The processes that determine the time scale to circularize the debris orbits and allow an accretion torus to form are discussed. This time scale and the time scales for radiative cooling and accretion inflow determine the onset and duration of the subsequent flare in the AGN luminosity. 22 refs.

CRITICAL PHENOMENA AND SELF-SIMILARITY IN THE GRAVITATIONAL COLLAPSE OF RADIATION FLUID

We observe critical phenomena in spherical collapse of radiation fluid. A sequence of spacetimes

Observation of critical phenomena and self-similarity in the gravitational collapse of radiation fluid

\cal{S}[\eta]

Physical processes in eclipsing pulsars: Eclipse mechanisms and diagnostics

is numerically computed, containing models (

Boosted three-dimensional black-hole evolutions with singularity excision

\eta\ll 1

Do OB runaway stars have pulsar companions

) that adiabatically disperse and models (

GRAVITATIONAL WAVE EXTRACTION AND OUTER BOUNDARY CONDITIONS BY PERTURBATIVE MATCHING

\eta\gg 1

Stable Characteristic Evolution of Generic Three-Dimensional Single-Black-Hole Spacetimes

) that form a black hole. Near the critical point (

Time dependence of particle creation from accelerating mirrors

\eta_c

Photometry and the light curve of the optical counterpart of the eclipsing millisecond pulsar 1957+20

), evolutions develop a self-similar region within which collapse is balanced by a strong, inward-moving rarefaction wave that holds