![]() relationships between the three main components of an XCT system are incorporated into the parameters of a projective geometry model. To explain the nonuniform temperature of PSR J0821-4300 may require a crustal field that is much stronger than the external, global dipole field. X-ray computed tomography (XCT) is an imaging technique that employs the attenuating properties of a medium as x-rays propagate through it. We also present a new upper limit on the period derivative of \dot (2σ), which limits the global dipole magnetic field to B s < 2.0 × 10 11 G, confirming PSR J0821-4300 as an "anti-magnetar." We discuss the results in the context of observations and theories of nonuniform surface temperature on isolated NSs of both weak and strong magnetic field. Including a cosine-beamed pattern for the emitted intensity modifies the result, decreasing the angles to (84°, 3°) however this model is not statistically distinguishable from the isotropic emission case. The best-fit spectral model for this geometry requires that the temperatures of the two emission spots differ by a factor of 2 and their areas by a factor of ~20. For a nominal radius of R = 12 km and distance D = 2.2 kpc, we find (ξ, ψ) = (86°, 6°), with 1σ error ellipse of (2°, 1°) this solution is degenerate in the two angles. The geometric model of the X-ray computer vision system establishes the relationship between 3D coordinates of the object under test and their corresponding 2D digital X-ray image coordinates. By comparing the recorded pulse modulation and phase to the model predictions, we strongly constrain the hot-spot pole (ξ) and the line-of-sight (ψ) angles with respect to the spin axis. We show that a pair of thermal, antipodal hot spots on the neutron star (NS) surface is able to fully account for the pulsar's double blackbody spectrum and energy-dependent pulse profile, including the observed 180° phase reversal at ≈1.2 keV. We conclude that the majority of the UV variability is therefore intrinsic, connected to mass accretion rate fluctuations in the warm Comptonisation region.We present a model for the unusual X-ray pulse profiles of PSR J0821-4300, the compact central object in supernova remnant Puppis A. Results on lower Eddington fraction AGN have emphasised the contribution from reverberation from larger scales (the broad line region), but reverberation induces lags on similar timescales to the smoothing, producing a larger delay than is compatible with the data. We present a model for the unusual X-ray pulse proles of PSR J08214300, the compact central object in su-pernova remnant Puppis A. We present a model for the unusual X-ray pulse profiles of PSR J0821-4300, the compact central object in supernova remnant Puppis A. Halpern 1 Columbia Astrophysics Laboratory. The soft X-rays (connected to the UV in the warm Comptonisation model) are more variable than the hard, but again contain too much fast variability to match the observed smoother variability seen in the UV. MODELING THE SURFACE X-RAY EMISSION AND VIEWING GEOMETRY OF PSR J08214300 IN PUPPIS A E. Increasing the coronal scale height to ~100 R g improves the match to the observed amplitude of UV variability as the disc subtends a larger solid angle, but results in too much fast variability to match the UV data. Illumination from a hard X-ray corona with height ~10 R g produces minimal UV variability. X - ray and gravi- tational lensing data, we find good agreement between the X - ray. Proposed IGCT geometry shown with the x-ray beam at one position. ( b ) The arc geometry predicted by our best - fit mass model. Unlike the lower Eddington fraction AGN (NGC 4151 and NGC 5548 at L/L Edd ~ 0.02 and 0.03 respectively), the SED of Akn 120 (L ~ 0.05L Edd) is dominated by the UV, restricting the impact of reverberating hard X-rays by energetics alone. not acquire sufficient volumetric data because of the diverg- ing x-ray beam in the. We model the spectral energy distribution including an outer standard disc (optical), an intermediate warm Comptonisation region (UV and soft X-ray) and a hot corona (hard X-rays). It allows for data reduction, model-independent data analysis, particle size. The hard X-rays (1-10 keV) show large amplitude, fast (few-day) variability, so we expect reverberation from the disc to produce UV variability from the varying hard X-ray illumination. Small angle X-ray scattering for nanomaterial analysis applications. However, this important constraint is often neglected in the X-ray data analysis. 2014) and then gives a crucial test of the self-consistency of a model. This quantity is strictly determined for a given geometry (see e.g.Dauser et al. Astronomical data generally consists of 2 or more high-resolution axes, e.g., X,Y position on the sky or wavelength and position-along-one-axis (long-slit spectrometer). We explore the accretion geometry in Arakelian 120 using intensive UV and X-ray monitoring from Swift. direct spectral component from the X-ray source. ![]()
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