9,356 research outputs found
A Fourier-Based Algorithm for Modelling Aberrations in HETE-2's Imaging System
The High-Energy Transient Explorer (HETE-2), launched in October 2000, is a
satellite experiment dedicated to the study of gamma-ray bursts in a very wide
energy range from soft X-ray to gamma-ray wavelengths. The intermediate X-ray
range (2-30keV) is covered by the Wide-field X-ray Monitor WXM, a coded
aperture imager. In this article, an algorithm for reconstructing the positions
of gamma-ray bursts is described, which is capable of correcting systematic
aberrations to approximately 1 arcmin throughout the field of view.
Functionality and performance of this algorithm have been validated using data
from Monte Carlo simulations as well as from astrometric observations of the
X-ray source Scorpius X-1.Comment: 14 pages, 9 figures, 2 tables; Nucl.Instr.Meth., in pres
A Deep Optical Observation for an Enigmatic Unidentified Gamma-Ray Source 3EG J1835+5918
We report a deep optical imaging observation by the Subaru telescope for a
very soft X-ray source RX J1836.2+5925, which has been suspected to be an
isolated neutron star associated with the brightest as-yet unidentified EGRET
source outside the Galactic plane, 3EG J1835+5918. An extended source having a
complex, bipolar shape is found at B ~ 26, and this might be an extended pulsar
nebular whose flux is about 5-6 orders of magnitude lower than gamma-ray flux,
although finding a galaxy of this magnitude by chance in the error circle is of
order unity. We have found two even fainter, possibly point sources at B ~ 28,
although their detections are not firm because of low signal-to-noise. If the
extended object of B ~ 26 is a galaxy and not related to 3EG J1835+5918, a
lower limit on X-ray/optical flux ratio is set as f_X/f_B >~ 2700, giving a
further strong support of the neutron-star identification of 3EG J1835+5918.
Interestingly, if either of the two sources at B ~ 28 is the real counterpart
of RX J1836.2+5925 and thermal emission from the surface of an isolated neutron
star, the temperature and distance to the source become ~ 4 x 10^5K and ~300pc,
respectively, showing a striking similarity of its spectral energy distribution
to the proto-type radio-quiet gamma-ray pulsar Geminga. No detection of
nonthermal hard X-ray emission is consistent with the ASCA upper limit, if the
nonthermal flux of 3EG J1835+5918/RX J1836.2+5925 is at a similar level with
that of Gemiga.Comment: PASJ Letters in press. (Received March 26; Accepted May 17
Flow induced force of labyrinth seal
Flow induced instability force due to a labyrinth seal is analyzed. An approximate solution is given for the partial differential equation representing the flow in labyrinth seal and it is compared with the finite difference method in order to verify the accuracy of both methods. The effects of difference of inlet and outlet pressures of the seal, deflection of pressure and mass flow from the steady state, rotor diameter, seal clearance, seal interval and seal number on the flow induced force of the seal are investigated and it is known that some of these factors are very influential on the flow induced force
A Note on String Field Theory in the Temporal Gauge
In this note, we review the recent developments in the string field theory in
the temporal gauge. (Based on a talk presented by N.I. in the workshop {\it
Quantum Field Theory, Integrable Models and Beyond}, Yukawa Institute for
Theoretical Physics, Kyoto University, 14-18 February 1994.)Comment: 20 pages, KEK-TH-411, LaTex fil
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