81 research outputs found
A Report on Overseas Teaching Practicum by Graduate Students in Elementary/Secondary Schools in the United States(Ⅹ)
This short paper reports on the 10th overseas teaching practicum in the United States by 8 graduate students of Hiroshima University, Japan, partly organized by Hiroshima University Global Partnership School Center (GPSC). This year marks the 10-year anniversary of this project since its start. This year’s participants were students of Graduate School of Education and Graduate School for International Development and Cooperation (IDEC). They observed and conducted lessons in English in four local public schools in North Carolina. This project had the following three aims: 1) to self-develop practical instructional competence by teaching pupils with different cultural backgrounds; 2) to enhance the abilities in developing teaching materials through hands-on teaching experiences in English; and 3) to acquire the abilities to design, implement and evaluate programs for promoting global partnership. Like previous years, their teachings were very positively covered by the local newspapers and websites. Later, the project was followed by cross-cultural field study visits to NC State Capitol, Raleigh and the U.S. Capitol, Washington, D.C. It is hoped that this intensive experience will raise the prospective teachers’ global awareness and confidence in teaching
Suzaku Observations of the Non-thermal Supernova Remnant HESS J1731-347
A detailed analysis of the nonthermal X-ray emission from the North-Western
and Southern parts of the supernova remnant (SNR) HESS J1731347 with {\it
Suzaku} is presented. The shell portions covered by the observations emit hard
and line-less X-rays. The spectrum can be reproduced by a simple absorbed
power-law model with a photon index of 1.8-2.7 and an absorption
column density of (1.0-2.1) cm. These
quantities change significantly from region to region; the North-Western part
of the SNR has the hardest and most absorbed spectrum. The Western part of the
X-ray shell has a smaller curvature than North-Western and Southern shell
segments. A comparison of the X-ray morphology to the Very High Energy (VHE)
gamma-ray and radio images was performed. The efficiency of electron
acceleration and emission mechanism in each portion of the shell are discussed.
Thermal X-ray emission from the SNR was searched for but could not be detected
at a significant level.Comment: 23 pages, 28 figures, ApJ, in pres
The ASTRO-H X-ray Observatory
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly
successful X-ray missions initiated by the Institute of Space and Astronautical
Science (ISAS). ASTRO-H will investigate the physics of the high-energy
universe via a suite of four instruments, covering a very wide energy range,
from 0.3 keV to 600 keV. These instruments include a high-resolution,
high-throughput spectrometer sensitive over 0.3-2 keV with high spectral
resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in
the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers
covering 5-80 keV, located in the focal plane of multilayer-coated, focusing
hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12
keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and
a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the
40-600 keV band. The simultaneous broad bandpass, coupled with high spectral
resolution, will enable the pursuit of a wide variety of important science
themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical
Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to
Gamma Ray
The Quiescent Intracluster Medium in the Core of the Perseus Cluster
Clusters of galaxies are the most massive gravitationally-bound objects in
the Universe and are still forming. They are thus important probes of
cosmological parameters and a host of astrophysical processes. Knowledge of the
dynamics of the pervasive hot gas, which dominates in mass over stars in a
cluster, is a crucial missing ingredient. It can enable new insights into
mechanical energy injection by the central supermassive black hole and the use
of hydrostatic equilibrium for the determination of cluster masses. X-rays from
the core of the Perseus cluster are emitted by the 50 million K diffuse hot
plasma filling its gravitational potential well. The Active Galactic Nucleus of
the central galaxy NGC1275 is pumping jetted energy into the surrounding
intracluster medium, creating buoyant bubbles filled with relativistic plasma.
These likely induce motions in the intracluster medium and heat the inner gas
preventing runaway radiative cooling; a process known as Active Galactic
Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus
cluster core, which reveal a remarkably quiescent atmosphere where the gas has
a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from
the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s
is found across the 60 kpc image of the cluster core. Turbulent pressure
support in the gas is 4% or less of the thermodynamic pressure, with large
scale shear at most doubling that estimate. We infer that total cluster masses
determined from hydrostatic equilibrium in the central regions need little
correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July
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