595 research outputs found
Time Dependent Modeling of the Markarian 501 X-ray and TeV Gamma-Ray Data Taken During March and April, 1997
If the high-energy emission from TeV blazars is produced by the Synchrotron
Self-Compton (SSC) mechanism, then simultaneous X-ray and Gamma-ray
observations of these objects are a powerful probe of the electron (and/or
positron) populations responsible for this emission. Understanding the emitting
particle distributions and their evolution in turn allow us to probe physical
conditions in the inner blazar jet and test, for example, various acceleration
scenarios. By constraining the SSC emission model parameters, such observations
also allow us to predict the intrinsic (unabsorbed) Gamma-ray spectra of these
sources, a major uncertainty in current attempts to use the observed Gamma-ray
spectra to constrain the intensity of the extragalactic background at
optical/infrared wavelengths. As a next step in testing the SSC model and as a
demonstration of the potential power of coordinated X-ray and Gamma-ray
observations, we attempt to model in detail the X-ray and Gamma-ray light
curves of the TeV Blazar Mrk 501 during its April-May 1997 outburst using a
time dependent SSC emission model. Extensive, quasi-simultaneous X-ray and
gamma-ray coverage exists for this period. We discuss and explore
quantitatively several of the flare scenarios presented in the literature. We
show that simple two-component models (with a soft, steady X-ray component plus
a variable SSC component) involving substantial pre-acceleration of electrons
to Lorentz factors on the order of 1E+5 describe the data train surprisingly
well. All considered models imply an emission region that is strongly out of
equipartition and low radiative efficiencies (ratio between kinetic jet
luminosity and comoving radiative luminosity) of 1 per-mill and less.Comment: 16 pages, Refereed Manuscript. Minor changes to previous versio
Galactic Models of Gamma-Ray Bursts
We describe observational evidence and theoretical calculations which support
the high velocity neutron star model of gamma-ray bursts. We estimate the
energetic requirements in this model, and discuss possible energy sources. we
also consider radiative processes involved in the bursts.Comment: 16 pages Latex file in revtex format. Fourteen postscript figures
come in a separate file. To appear in the Proceedings of the 1995 La Jolla
Workshop "High Velocity Neutron Stars and Gamma-Ray Bursts", eds. R.
Rorschild etal., AIP, New Yor
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