452 research outputs found
Multi-resolution analysis of the H.E.S.S. Galactic Survey Sources and Search for Counterparts in CO and HI data.
To appear in proceedings 29th International Cosmic Ray Conference (ICRC 2005)From May to July 2004, the central radian of the Galactic Plane was scanned by the H.E.S.S. (High Energy Stereoscopic System) telescopes at energies above 200 GeV. This survey was performed from - to + in latitude, for a total of 230 hours, revealing eight new VHE sources at a significance level greater than 6(standard deviations). We present a multi-resolution analysis of these sources based on a continuous wavelet transformation (CWT). Using CO and HI data, we investigate the possible associations of the potential counterparts proposed in [1], with sites of enhanced interstellar matter density
Fermi Detection of the Pulsar Wind Nebula HESS J1640-465
We present observations of HESS J1640-465 with the Fermi-LAT. The source is
detected with high confidence as an emitter of high-energy gamma-rays. The
spectrum lacks any evidence for the characteristic cutoff associated with
emission from pulsars, indicating that the emission arises primarily from the
pulsar wind nebula. Broadband modeling implies an evolved nebula with a low
magnetic field resulting in a high gamma-ray to X-ray flux ratio. The Fermi
emission exceeds predictions of the broadband model, and has a steeper
spectrum, possibly resulting from a distinct excess of low energy electrons
similar to what is inferred for both the Vela X and Crab pulsar wind nebulae.Comment: 6 pages, 5 figures, accepted for publication in Ap
High Resolution X-ray Observations of the Pulsar Wind Nebula Associated with the Gamma-ray Source HESSJ1640-465
We present a Chandra X-ray observation of the very high energy -ray
source HESSJ1640-465. We identify a point source surrounded by a diffuse
emission that fills the extended object previously detected by XMM Newton at
the centroid of the HESS source, within the shell of the radio supernova
remnant (SNR) G338.3-0.0. The morphology of the diffuse emission strongly
resembles that of a pulsar wind nebula (PWN) and extends asymmetrically to the
South-West of a point-source presented as a potential pulsar. The spectrum of
the putative pulsar and compact nebula are well-characterized by an absorbed
power-law model which, for a reasonable value of , exhibit an index of 1.1 and 2.5 respectively, typical of
Vela-like PWNe. We demonstrate that, given the HI absorption features
observed along the line of sight, the SNR and the HII surrounding region are
probably connected and lie between 8 kpc and 13 kpc. The resulting age of the
system is between 10 and 30 kyr. For a 10 kpc distance (also consistent with
the X-ray absorption) the 2-10 keV X-ray luminosities of the putative pulsar
and nebula are and
(). Both the flux ratio of and the total luminosity of this system predict a pulsar spin-down
power around . We finally
consider several reasons for the asymmetries observed in the PWN morphology and
discuss the potential association with the HESS source in term of a
time-dependent one-zone leptonic model.Comment: 35 pages, 9 figure
Constraining leptonic emission scenarios for the PeVatron candidate HESS J1702-420 with deep XMM-Newton observations
The unidentified TeV source HESS J1702-420 has recently been proposed as a
new hadronic PeVatron candidate, based on the discovery of a small-scale
emission sub-region with extremely hard gamma-ray spectrum up to 100 TeV (named
HESS J1702-420A). Given the difficulty to discriminate between a hadronic or
leptonic origin of the TeV emission, based on the H.E.S.S. measurement alone,
we opted for a multi-wavelength approach. A deep X-ray observation was carried
out using the XMM-Newton satellite, with the goal of probing a possible
association with a hidden leptonic accelerator. No evidence of a clear
counterpart for HESS J1702-420A was found in the X-ray data. After excluding an
association with all nearby X-ray point sources, we derived strict upper limits
on the diffuse X-ray emission and average magnetic field in the HESS J1702-420A
region. We additionally report the serendipitous discovery of a new extended
X-ray source, whose association with HESS J1702-420A is not obvious but cannot
be ruled out either. A set of scripts dedicated to the multi-wavelength
modeling of X-ray and gamma-ray data, based on Gammapy, Naima and Xspec, was
developed in the context of this work and is made publicly available along with
this paper.Comment: Accepted for publication in Astronomy & Astrophysics, 13 pages, 11
figures, 3 table
TDI noises transfer functions for LISA
The LISA mission is the future space-based gravitational wave (GW)observatory of the European Space Agency. It is formed by 3 spacecraftexchanging laser beams in order to form multiple real and virtualinterferometers. The data streams to be used in order to extract the largenumber and variety of GW sources are Time-Delay Interferometry (TDI) data. Oneimportant processing to produce these data is the TDI on-ground processingwhich recombines multiple interferometric on-board measurements to removecertain noise sources from the data such as laser frequency noise or spacecraftjitter. The LISA noise budget is therefore expressed at the TDI level in orderto account for the different TDI transfer functions applied for each noisesource and thus estimate their real weight on mission performance. In order toderive a usable form of these transfer functions, a model of the beams, themeasurements, and TDI have been developed, and several approximation have beenmade. A methodology for such a derivation has been established, as well asverification procedures. It results in a set of transfer functions, which arenow used by the LISA project, in particular in its performance model. Usingthese transfer functions, realistic noise curves for various instrumentalconfigurations are provided to data analysis algorithms and used for instrumentdesign.<br
Evaluation of Long-Term Respiratory Effects of Exposure to Welding Fumes
Abstract Welding fumes are known to cause respiratory health problems. We aimed to evaluate the long-term respiratory effects of exposure to welding fumes. Inception cohorts of welding, plumbing, and heating apprentices were prospectively contacted 7-17 years post-apprenticeship. Questionnaires, as well as spirometry and non-specific bronchial hyperresponsiveness (NSBHR) tests were repeatedly administered. A long-term evaluation was done in 71 former apprentices at the Hôpital du Sacré-Cœur de Montréal between 2013 and 2017. Post-apprenticeship exposure to welding fumes and gasses was evaluated using three methods: self-report, expert assessment and the asthmaspecific job exposure matrix. The incidence of wheezing and excessive lung function decline, given continued post-apprenticeship exposure to welding fumes, was estimated using Cox regression. Incident wheezing was found in 18.8% of subjects, and excessive lung function decline was observed in 12.7% of subjects. All three exposure assessment methods consistently showed that subjects with continued, post-apprenticeship exposure to welding fumes or gasses had a lower risk of developing wheezing symptoms or excessive decline in lung function, although none of the associations were significant. In conclusion, continued post-apprenticeship exposure to welding fumes does not seem to increase the risk of developing long-term respiratory outcomes.Keywords: apprentices, lung function, occupational, welding
Abstrak Asap dan gas pengelasan (welding fumes and gasses) diketahui dapat menyebabkan masalah pernapasan. Penelitian ini dilakukan untuk mengevaluasi efek pernapasan jangka panjang dari pajanan asap dan gas pengelasan. Mantan peserta sekolah kejuruan pengelasan secara prospektif dihubungi 7-17 tahun pasca-pendidikan. Subjek penelitian melengkapi kuesioner, uji spirometri dan uji bronkus non-spesifik. Evaluasi jangka panjang dilakukan pada 71 subjek di Hôpital du Sacré-Cœur de Montréal antara tahun 2013 dan 2017. Pajanan asap dan gas pengelasan pascapendidikan dievaluasi menggunakan tiga metode: laporan oleh pekerja, penilaian oleh ahli dan penggunaan matriks pajanan di tempat kerja pekerjaan khusus. Hubungan antara pajanan asap dan gas pengelasan dengan insidens mengi dan penurunan fungsi paru-paru berlebihan dievaluasi menggunakan regresi Cox. Insidens mengi ditemukan pada 18,8% subjek, dan penurunan fungsi paru berlebihan diamati pada 12,7% subjek. Ketiga metode penilaian pajanan secara konsisten menunjukkan bahwa subjek dengan pajanan asap dan gas pengelasan pasca-pendidikan memiliki risiko lebih rendah terkena gejala mengi atau penurunan fungsi paru-paru yang berlebihan, meskipun tidak ada hubungan yang bermakna. Sebagai kesimpulan, pajanan asap dan gas pengelasan jangka panjang tampaknya tidak meningkatkan risiko penurunan fungsi pernapasan.Kata kunci: fungsi paru, pekerjaan, asap dan gas pengelasa
The Infrared Detection of the Pulsar Wind Nebula in the Galactic Supernova Remnant 3C 58
We present infrared observations of 3C 58 with the Spitzer Space Telescope
and the Canada-France-Hawaii Telescope. Using the IRAC camera, we have imaged
the entire source resulting in clear detections of the nebula at 3.6 and 4.5
microns. The derived flux values are consistent with extrapolation of the X-ray
spectrum to the infrared band, demonstrating that any cooling break in the
synchrotron spectrum must occur near the soft X-ray band. We also detect the
torus surrounding PSR J0205+6449, the 65 ms pulsar that powers 3C 58. The torus
spectrum requires a break between the infrared and X-ray bands, and perhaps
multiple breaks. This complex spectrum, which is an imprint of the particles
injected into the nebula, has considerable consequences for the evolution of
the broadband spectrum of 3C 58. We illustrate these effects and discuss the
impact of these observations on the modeling of broadband spectra of pulsar
wind nebulae.Comment: 4 pages, 4 figures, accepted for publication in ApJ Letter
Vaginal temperature and collar activity variations in relation to fecal progestagens of captive moose
publishedVersio
Effects of copper on the early development of Xenopus laevis: the case of CuSO4 and Bordeaux mixture solutions
Not available
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