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2S 0921−630 is an eclipsing low-mass X-ray binary (LMXB) with an orbital period of ∼9 d. Past X-ray observations have revealed that 2S 0921−630 has an extended accretion disk corona (ADC), from which most of the X-rays from the system are emitted. We report the result of our Suzaku archival data analysis of 2S 0921−630. The average X-ray spectrum is reproduced with a blackbody emission (kT bb ∼ 0.3 keV) Comptonized by optically thick gas ("Compton cloud"; optical depth τ ∼ 21) with a temperature of ∼2 keV, combined with 13 emission lines. We find that most of the emission lines correspond to highly ionized atoms: O, Ne, Mg, Si, S, Ar, and Fe. A Kα emission line and an absorption edge of semi-neutral iron (Fe  textsci– textscxvii) are also detected. The semi-neutral iron Kα line is significantly broad, with a width of 0.11 ± 0.02 keV in sigma, which corresponds to the Doppler broadening by the Kepler motion at a radius of ∼109 cm. We suggest that the observed semi-neutral iron line originates at the inner part of the accretion disk in the immediate outside of the Compton cloud, i.e., the Compton cloud may have a radius of ∼109 cm. [ABSTRACT FROM AUTHOR]

The Compton camera is a gamma ray imaging device expected to provide clinically relevant images in the SPECT applications where collimated cameras are sub-optimal. Its imaging performances depend not only on the design of the detection system but also on choices related to tomographic reconstruction. The aim of this work is to show that the accuracy in modelling the acquisition largely influences the quality of the images. For this purpose, we restrict here to Doppler broadening models in conjunction with the list-mode maximum likelihood expectation maximization (LM-MLEM) algorithm. The study was carried out with Monte-Carlo simulation. We show that the reconstructed point spread function is location-dependent when the model is not accurate, and the usual elongation artefacts well-known in Compton camera imaging will appear. The model we propose allows us to reconstruct isolated point sources and more complex non-uniform sources with improved resolution even in the direction orthogonal to the camera. [ABSTRACT FROM AUTHOR]

• GH shift is controlled and modified under the effects of Kerr nonlinearity, Doppler broadening and Compton scattering. • Maximum GH-shift in the reflection/transmission is investigated to ±3 λ. • Above, the ϕ c = π / 6 GH-shift is saturated at λ in the reflection. • GH-shift is the function of control fields, Kerr nonlinearity, Doppler broadening. • Gh-Shift changes with incident and Compton scattered angles. • The results have applications in nano-optics, trapping of optical data, micro-optics. Reflection, transmission as well as absorption coefficients and the corresponding Goos Hänchen shift in reflection and transmission is controlled and modified under the effects of Kerr nonlinearity, Doppler broadening as well as Compton scattering. The summation of the absolute values of these coefficients gives a unit value in the presence of all these effects. Modification of the coefficients follows the normalization condition. Maximum GH-shift in the reflection/transmission is investigated to ± 3 λ. Above ϕ c = π / 6 , the GH-shift is saturated at the value λ in both reflection/transmission. The positive as well as negative GH-shift is measured in the absence and presence of Compton scattered reflected/transmitted beam. The GH-shift is the function of control fields, Kerr nonlinearity, incoherent effect of Doppler broadening and incident as well as the Compton scattered angles. The results show potential applications in nano-optics, trapping of optical data, micro-optics, acoustics, sensor technology and plasma physics. [ABSTRACT FROM AUTHOR]