scholarly journals A measurement-based X-ray source model characterization for CT dosimetry computations

2015 ◽  
Vol 16 (6) ◽  
pp. 386-400 ◽  
Author(s):  
Mitchell Sommerville ◽  
Yannick Poirier ◽  
Mauro Tambasco
Keyword(s):  
Source Model ◽  
X Ray ◽  
Ct Dosimetry

scholarly journals Testing a double AGN hypothesis for Mrk 273

2018 ◽  
Vol 611 ◽  
pp. A71 ◽  
Author(s):  
K. Iwasawa ◽  
V. U ◽  
J. M. Mazzarella ◽  
A. M. Medling ◽  
D. B. Sanders ◽  
...  
Keyword(s):  
Alternative Explanation ◽  
Source Model ◽  
Spectral Slope ◽  
Line Flux ◽  
Ionized Gas ◽  
X Ray ◽  
Gas Kinematics ◽  
N Source ◽  
Seyfert Nucleus ◽  
Luminous Infrared Galaxy

The ultra-luminous infrared galaxy (ULIRG) Mrk 273 contains two infrared nuclei, N and SW, separated by 1 arcsecond. A Chandra observation has identified the SW nucleus as an absorbed X-ray source with NH ~ 4 × 1023 cm−2 but also hinted at the possible presence of a Compton-thick AGN in the N nucleus, where a black hole of ~109 M⊙ is inferred from the ionized gas kinematics. The intrinsic X-ray spectral slope recently measured by NuSTAR is unusually hard (Γ ~ 1.3) for a Seyfert nucleus, for which we seek an alternative explanation. We hypothesize a strongly absorbed X-ray source in N, of which X-ray emission rises steeply above 10 keV, in addition to the known X-ray source in SW, and test it against the NuSTAR data, assuming the standard spectral slope (Γ = 1.9). This double X-ray source model gives a good explanation of the hard continuum spectrum, deep Fe K absorption edge, and strong Fe K line observed in this ULIRG, without invoking the unusual spectral slope required for a single source interpretation. The putative X-ray source in N is found to be absorbed by NH = 1.4+0.7−0.4 × 1024 cm−2. The estimated 2−10 keV luminosity of the N source is 1.3 × 1043 erg s−1, about a factor of 2 larger than that of SW during the NuSTAR observation. Uncorrelated variability above and below 10 keV between the Suzaku and NuSTAR observations appears to support the double source interpretation. Variability in spectral hardness and Fe K line flux between the previous X-ray observations is also consistent with this picture.

Energy of microwave-emitting electrons and hard X-ray/microwave source model in solar flares

Solar Physics ◽  
1986 ◽  
Vol 105 (1) ◽  
pp. 73-85 ◽  
Author(s):  
Nariaki Nitta ◽  
Takeo Kosugi
Keyword(s):  
Solar Flares ◽  
Source Model ◽  
Microwave Source ◽  
X Ray

scholarly journals Volumetric Source Model to Predict Productivity of Fractured Horizontal Well in Naturally Fractured Reservoirs

2015 ◽  
Vol 8 (1) ◽  
pp. 373-384 ◽  
Author(s):  
Tianhui Wang ◽  
Haitao Li ◽  
Junchao Wang ◽  
Yunlin Jia ◽  
Lifeng Liu
Keyword(s):  
Horizontal Well ◽  
Fractured Reservoirs ◽  
Source Model ◽  
Naturally Fractured Reservoirs ◽  
X Ray Diffraction ◽  
Cyclic Voltammetric ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Fractured Horizontal Well ◽  
Square Planar

A novel dinuclear Cu(II) complex material has been synthesized by the reaction of 1, 2-phenylenedioxydiacetic acid, 1,10-phenantroline (phen) and Cu(CHCOO)·HO. And it has been characterized by elemental analysis, IR, UV and single crystal X-ray diffraction. The crystal belongs to tetragonal, space group I4/ with = = 25.381(4) Å, = 32.044(6) Å, = 20643(6) Å, = 16, D= 1.395 g·cm, = 0.898 mm, (000) = 8896, and final = 0.1026, = 0.3142. The structural analysis shows that two Cu(II) atoms adopt different coordination modes, Cu has five-coordination with a trigonal bipyramidal configuration, and Cu has four-coordination with a distorted square planar configuration. The cyclic voltammetric behaviour of the dinuclear Cu(II) complex has been investigated.

Experimental validation of a kilovoltage x-ray source model for computing imaging dose

2014 ◽  
Vol 41 (4) ◽  
pp. 041915 ◽  
Author(s):  
Yannick Poirier ◽  
Alexei Kouznetsov ◽  
Brandon Koger ◽  
Mauro Tambasco
Keyword(s):  
Experimental Validation ◽  
Source Model ◽  
X Ray ◽  
Imaging Dose

scholarly journals X-Ray modeling of η Carinae & WR 140 from SPH simulations

2010 ◽  
Vol 6 (S272) ◽  
pp. 630-631
Author(s):  
Christopher M. P. Russell ◽  
Michael F. Corcoran ◽  
Atsuo T. Okazaki ◽  
Thomas I. Madura ◽  
Stanley P. Owocki
Keyword(s):  
Point Source ◽  
Mass Loss Rate ◽  
Source Model ◽  
Light Curves ◽  
X Rays ◽  
Early Recovery ◽  
X Ray ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Η Car

AbstractThe colliding wind binary (CWB) systems η Carinae and WR140 provide unique laboratories for X-ray astrophysics. Their wind-wind collisions produce hard X-rays that have been monitored extensively by several X-ray telescopes, including RXTE. To interpret these RXTE X-ray light curves, we apply 3D hydrodynamic simulations of the wind-wind collision using smoothed particle hydrodynamics (SPH). We find adiabatic simulations that account for the absorption of X-rays from an assumed point source of X-ray emission at the apex of the wind-collision shock cone can closely match the RXTE light curves of both η Car and WR140. This point-source model can also explain the early recovery of η Car's X-ray light curve from the 2009.0 minimum by a factor of 2-4 reduction in the mass loss rate of η Car. Our more recent models account for the extended emission and absorption along the full wind-wind interaction shock front. For WR140, the computed X-ray light curves again match the RXTE observations quite well. But for η Car, a hot, post-periastron bubble leads to an emission level that does not match the extended X-ray minimum observed by RXTE. Initial results from incorporating radiative cooling and radiative forces via an anti-gravity approach into the SPH code are also discussed.

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