2,540 research outputs found
Statistical analysis of general aviation VG-VGH data
To represent the loads spectra of general aviation aircraft operating in the Continental United States, VG and VGH data collected since 1963 in eight operational categories were processed and analyzed. Adequacy of data sample and current operational categories, and parameter distributions required for valid data extrapolation were studied along with envelopes of equal probability of exceeding the normal load factor (n sub z) versus airspeed for gust and maneuver loads and the probability of exceeding current design maneuver, gust, and landing impact n sub z limits. The significant findings are included
Identification of 8 INTEGRAL hard X-ray sources with Chandra
We report the results of identification of 8 hard X-ray sources discovered by
the INTEGRAL observatory during the ongoing all-sky survey. These sources have
been observed by Chandra. In 6 cases a bright X-ray source was found within the
INTEGRAL localization region, which permitted to unambigously identify 5 of the
objects with nearby galaxies, implying that they have an active galactic
nucleus (AGN), whereas one source is likely an X-ray binary in LMC. 4 of the 5
newly discovered AGNs have measured redshifts in the range 0.025-0.055. The
X-ray spectra reveal the presence of significant amounts of absorbing gas (NH
in the range 10^22-10^24 cm^-2) in all 5 AGNs, demonstrating that INTEGRAL is
starting to fill in the sample of nearby obscured AGNs.Comment: 4 pages, 2 figures, corrected Fig.
Haff disease: from the Baltic Sea to the U.S. shore.
Haff disease, identified in Europe in 1924, is unexplained rhabdomyolysis in a person who ate fish in the 24 hours before onset of illness. We describe a series of six U.S. patients from 1997 and report new epidemiologic and etiologic aspects. Although Haff disease is traditionally an epidemic foodborne illness, these six cases occurred in two clusters and as one sporadic case
Unveiling the nature of IGR J16493-4348 with IR spectroscopy
The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) is discovering
a large number of new hard X-ray sources, many of them being HMXBs. The
identification and spectral characterization of their optical/infrared
counterparts is a necessary step in undertaking a detailed study of these
systems. In a previous paper, we presented spectral analyses and
classifications of six newly discovered INTEGRAL sources. In this paper, we
extend the analysis to IGR J16493-4348. We used the ESO/VLT ISAAC spectrograph
to observe the proposed IR counterpart to the source, obtaining a Ks
medium-resolution spectrum (R = 500) with a signal-to-noise ratio (S/N) >150.
We classified the source by comparing with published atlases. We spectrally
classified the source as a B0.5-1 supergiant and estimated its interstellar
extinction. We compared the extinction derived from X-ray data with effective
interstellar extinction obtained from our data, discussing the absorption
component associated with the circumstellar environment.Comment: 4 pages, 1 figure, 3 tables. Accepted for publication in Astronomy
and Astrophysics
First Detection of HCO Absorption in the Magellanic System
We present the first detection of HCO absorption in the Magellanic
System. Using the Australia Telescope Compact Array (ATCA), we observed 9
extragalactic radio continuum sources behind the Magellanic System and detected
HCO absorption towards one source located behind the leading edge of the
Magellanic Bridge. The detection is located at LSR velocity of , with a full width at half maximum of and optical depth of .
Although there is abundant neutral hydrogen (HI) surrounding the sightline in
position-velocity space, at the exact location of the absorber the HI column
density is low, , and there is little evidence for dust
or CO emission from Planck observations. While the origin and survival of
molecules in such a diffuse environment remains unclear, dynamical events such
as HI flows and cloud collisions in this interacting system likely play an
important role.Comment: Accepted for publication in ApJ. 6 pages, 2 figures, 2 table
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