نتایج جستجو برای: ray spectrum
تعداد نتایج: 513243 فیلتر نتایج به سال:
The energy spectrum of cosmic-ray antiprotons ( &pmacr;'s) has been measured in the range 0.18-3.56 GeV, based on 458 &pmacr;'s collected by BESS in a recent solar-minimum period. We have detected for the first time a characteristic peak at 2 GeV of &pmacr;'s originating from cosmic-ray interactions with the interstellar gas. The peak spectrum is reproduced by theoretical calculations, implying...
The unfolding of a gamma ray spectrum experience many difficulties due to noise in the recorded data, that is based mainly on the change of photon energy due to scattering mechanisms (either in the detector or the medium), the accumulation of recorded counts in a fixed energy interval (the channel width of the detector) and finally the statistical fluctuation inside the detector. In order to de...
The BeppoSAX archive is currently the largest reservoir of high sensitivity simultaneous soft and hard-X ray data of Seyfert galaxies. From this database all the Seyfert galaxies (105 objects of which 43 are type I and 62 are type II) with redshift lower than 0.1 have been selected and analyzed in a homogeneous way (Dadina 2007). Taking advantage of the broad-band coverage of the BeppoSAX MECS ...
X-Ray is an ionizing electromagnetic radiation with a wide spectrum. A setting where this radiation is widely used is airport security units. This study was conducted to measure the level of momentary exposure to X-Ray in operators and personnel working in security gates of Imam Khomeini airport. In this cross-sectional study, the X-Ray machines used in security gates of Imam Khomeini airport a...
We report the discovery of a 200 mHz quasi-periodic oscillation (QPO) in the X-ray emission from a bright ultra-luminous X-ray source (ULX) Holmberg IX X-1 using a long XMM-Newton observation. The QPO has a centroid at νQPO = 202.5 +4.9 −3.8 mHz, a coherence Q ≡ νQPO/∆νFWHM ≈ 9.3 and an amplitude (rms) of 6% in the 0.2 − 10 keV band. This is only the second detection of a QPO from an ULX, after...
Diiuse galactic continuum-ray emission in the 0.75-30 MeV range from the inner Galaxy has been studied using data from COMPTEL on the Compton Observatory. Observations of the inner Galaxy from the Sky Survey have been used. The imaging properties of COMPTEL enable spatial analysis of the-ray distribution using model tting. A model based on atomic and molecular gas distributions in the Galaxy ha...
We observed the gamma-ray pulsar Geminga with the FUV-MAMA and NUV-MAMA detectors of the Space Telescope Imaging Spectrometer to measure the Geminga’s spectrum and pulsations in the ultraviolet. The slope of the far-ultraviolet (FUV) spectrum is close to that of a Rayleigh-Jeans spectrum, suggesting that the FUV radiation is dominated by thermal emission from the neutron star (NS) surface. The ...
We present an X-ray observation of the active giant β Cet, performedwith the LowEnergy Concentrator Spectrometer (LECS) on-board the SAX satellite. The resulting X-ray spectrum is well fit by an optically-thin plasma model with two discrete temperatures, and the inferred coronal metallicity is compatible both with the abundances derived from a re-analysis of the ASCA SIS spectrum of the same ob...
The terms X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) refer, respectively, to the structure in the X-ray absorption spectrum at low and high energies relative to the absorption edge. Routine analysis of EXAFS experiments generally makes use of simplified models and several many-body parameters, e.g. mean free paths, many-body amplitude facto...
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