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Title: "Highlights of the Swift GRB Mission"

Prof. David Burrows

Department of Astronomy and Astrophysics
Penn State University
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When:  Thursday, September 18 at 2 p.m.
Where: 2nd Floor Seminar Room

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Abstract:

I will discuss some of the major accomplishments of the Swift X-ray Telescope
in its first 3 years of operations, concentrating primarily on X-ray afterglows
and the recent "naked-eye GRB", GRB 080319B.  One of the major discoveries of
the Swift mission has been the discovery that X-ray flares are quite common in
GRB afterglows.  These flares have been widely interpreted as emission from
late-time internal shocks, providing evidence for long-lived central engine
activity, possibly from fall-back of material onto the accretion torus surrounding
the central black hole.  While this model provides a satisfactory explanation for
most X-ray flares, it does not seem to explain all flares, and there is growing
evidence pointing towards other mechanisms in some cases.  At the same time,
optical and X-ray afterglows do not always agree in their behavior, hinting that
more complex models of the afterglows are needed.  The recent "naked-eye" GRB 080319B
provides strong evidence requiring a complex multi-jet model to explain the optical
and X-ray afterglows, pointing towards one possible resolution of this problem.
I will discuss our current understanding of this issue and will end with some
possible future directions for research on gamma-ray burst afterglows.