October 15, 2010
15:00 h
VR II, room 158
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Steve Schulze, Science Institute, Univ. of Iceland
Title:
Gamma-ray bursts - probing matter at interstellar and intergalactic
scales
Abstract:
Gamma-ray bursts (GRBs) are transient sources in the gamma-rays lasting
fractions of a second up to hundreds of seconds. During an explosion a burst
outshines the visible universe in gamma-rays. Intriguingly, they occurred in the
distant universe many billion years ago. In addition to the gamma-ray emission, a GRB is
accompanied by an afterglow extending from radio to X-rays. Even an afterglow
outshines its host galaxy by a factor of 1,000-10,000 for several days. Due to their
immense brightness and the fact that they occur in the early universe, GRBs are
excellent background candles to study matter along the line-of-sight.
In this talk I present the results from two projects. In the first
project I studied the interstellar medium around GRBs in order to reveal the progenitor
of GRBs. The second project is about intervening absorbers at intergalactic
distances. The aim of this project is to find the photometric counterparts to the intervening
systems.
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October, 2010
15:00 h
VR II, room 158
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Hamid Keshmiri, Science Institute, Univ. of Iceland
Title:
Colorimetric resonant reflectance in optical
grating biosensor structures
Abstract: Optical grating biosensors allow detection of small chemical molecules
and cells using intrinsic properties in molecular scale. An optical
grating sensor may be optimized to provide an extremely narrow resonant
mode whose wavelength is particularly sensitive to modulations induced
by deposition of a biochemical material on its surface. In this
research, modeling of colorimetric resonant reflectance in optical
grating biosensors is presented. By changing the structure and
materials
of the sensor, some improvement in reflection sensitivity was achieved.
Ideas over the biological origins of photonic crystal nanostructures
are
also explored.
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