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I Negueruela - One of the best experts on this subject based on the ideXlab platform.

  • the be x ray transient v0332 53 evidence for a tilt between the orbit and the Equatorial Plane
    Monthly Notices of the Royal Astronomical Society, 1999
    Co-Authors: I Negueruela, P Roche, J Fabregat, M J Coe
    Abstract:

    We present optical and infrared observations of BQ Cam, the optical counterpart to the Be/X-ray transient system V0332+53. BQ Cam is shown to be an O8–9Ve star, which places V0332+53 at a distance of ∼7 kpc. Hα spectroscopy and infrared photometry are used to discuss the evolution of the circumstellar envelope. Owing to the low inclination of the system, parameters are strongly constrained. We find strong evidence for a tilt of the orbital Plane with respect to the circumstellar disc (presumably on the Equatorial Plane). Even though the periastron distance is only ≈10R*, during the present quiescent state the circumstellar disc does not extend to the distance of periastron passage. Under these conditions, X-ray emission is effectively prevented by centrifugal inhibition of accretion. The circumstellar disc is shown to be optically thick at optical and infrared wavelengths, which, together with its small size, is taken as an indication of tidal truncation.

  • the be x ray transient v0332 53 evidence for a tilt between the orbit and the Equatorial Plane
    arXiv: Astrophysics, 1999
    Co-Authors: I Negueruela, P Roche, J Fabregat, M J Coe
    Abstract:

    We present optical and infrared observations of BQ Cam, the optical counterpart to the Be/X-ray transient system V0332+53. BQ Cam is shown to be an O8-9Ve star, which places V0332+53 at a distance of ~7 kpc. H-alpha spectroscopy and infrared photometry are used to discuss the evolution of the circumstellar envelope. Due to the low inclination of the system, parameters are strongly constrained. We find strong evidence for a tilt of the orbital Plane with respect to the circumstellar disc (pressumably on the Equatorial Plane). Even though the periastron distance is only ~ 10 R_*, during the present quiescent state the circumstellar disc does not extend to the distance of periastron passage. Under these conditions, X-ray emission is effectively prevented by centrifugal inhibition of accretion. The circumstellar disc is shown to be optically dense at optical and infrared wavelengths, which together with its small size, is taken as an indication of tidal truncation.

M J Coe - One of the best experts on this subject based on the ideXlab platform.

  • the be x ray transient v0332 53 evidence for a tilt between the orbit and the Equatorial Plane
    Monthly Notices of the Royal Astronomical Society, 1999
    Co-Authors: I Negueruela, P Roche, J Fabregat, M J Coe
    Abstract:

    We present optical and infrared observations of BQ Cam, the optical counterpart to the Be/X-ray transient system V0332+53. BQ Cam is shown to be an O8–9Ve star, which places V0332+53 at a distance of ∼7 kpc. Hα spectroscopy and infrared photometry are used to discuss the evolution of the circumstellar envelope. Owing to the low inclination of the system, parameters are strongly constrained. We find strong evidence for a tilt of the orbital Plane with respect to the circumstellar disc (presumably on the Equatorial Plane). Even though the periastron distance is only ≈10R*, during the present quiescent state the circumstellar disc does not extend to the distance of periastron passage. Under these conditions, X-ray emission is effectively prevented by centrifugal inhibition of accretion. The circumstellar disc is shown to be optically thick at optical and infrared wavelengths, which, together with its small size, is taken as an indication of tidal truncation.

  • the be x ray transient v0332 53 evidence for a tilt between the orbit and the Equatorial Plane
    arXiv: Astrophysics, 1999
    Co-Authors: I Negueruela, P Roche, J Fabregat, M J Coe
    Abstract:

    We present optical and infrared observations of BQ Cam, the optical counterpart to the Be/X-ray transient system V0332+53. BQ Cam is shown to be an O8-9Ve star, which places V0332+53 at a distance of ~7 kpc. H-alpha spectroscopy and infrared photometry are used to discuss the evolution of the circumstellar envelope. Due to the low inclination of the system, parameters are strongly constrained. We find strong evidence for a tilt of the orbital Plane with respect to the circumstellar disc (pressumably on the Equatorial Plane). Even though the periastron distance is only ~ 10 R_*, during the present quiescent state the circumstellar disc does not extend to the distance of periastron passage. Under these conditions, X-ray emission is effectively prevented by centrifugal inhibition of accretion. The circumstellar disc is shown to be optically dense at optical and infrared wavelengths, which together with its small size, is taken as an indication of tidal truncation.

E C Hansen - One of the best experts on this subject based on the ideXlab platform.

  • light s bending angle in the Equatorial Plane of a kerr black hole
    Physical Review D, 2009
    Co-Authors: Savitri V Iyer, E C Hansen
    Abstract:

    We present here a detailed derivation of an explicit spin-dependent expression for the bending angle of light as it traverses in the Equatorial Plane of a spinning black hole. We show that the deflection produced in the presence of the black hole angular momentum explicitly depends on whether the motion of the light ray is in the direction, or opposite to the spin. Compared to the zero-spin Schwarzschild case, the bending angle is greater for direct orbits, and smaller for retrograde orbits, confirming our physical intuition about the loss of left-right symmetry from a lensing perspective. In addition, we show that for higher spins, the effect is more pronounced resulting in tighter winding of direct orbits with respect to the axis of rotation, and a higher degree of unwinding of retrograde orbits. A direct consequence of this effect is a shift in image positions in strong gravitational lensing.

Jonghyeon Lee - One of the best experts on this subject based on the ideXlab platform.

  • control and theoretical modeling of the growth process of aln six fold and multifold armed dendritic crystals
    Crystal Growth & Design, 2019
    Co-Authors: Hayk H Nersisyan, Wan Bae Kim, Seong Hun Lee, Bung Uk Yoo, Hyuk Choi, Hyun You Kim, Jonghyeon Lee
    Abstract:

    Through a combinatorial approach involving theory and experiments, this study investigated the mechanism of the dendritic growth of AlN microcrystals during the combustion of Al + 0.1AlF3 + kAl2O3 powder mixtures under nitrogen-rich conditions. The experimentally observed morphology of the dendritic AlN crystals is characterized by the six-fold branches that developed outward within an Equatorial Plane and secondary dendrites that grew above and below the Equatorial Plane. The physical mechanisms that lead to the shape-controlled synthesis of AlN dendritic crystals were studied through experimental analysis and theoretical investigation including density functional theory (DFT) calculation and phase-field (PF) crystal growth modeling. Based on the DFT-calculated surface energy values, an energy minimization argument was used to construct the AlN nucleus. PF crystal growth modeling provides the details of the sequential crystallization process of the dendritic AlN crystals. The results of this study provid...

  • Control and Theoretical Modeling of the Growth Process of AlN Six-fold and Multifold Armed Dendritic Crystals
    2019
    Co-Authors: Hayk H Nersisyan, Wan Bae Kim, Seong Hun Lee, Bung Uk Yoo, Hyuk Choi, Hyun You Kim, Jonghyeon Lee
    Abstract:

    Through a combinatorial approach involving theory and experiments, this study investigated the mechanism of the dendritic growth of AlN microcrystals during the combustion of Al + 0.1AlF3 + kAl2O3 powder mixtures under nitrogen-rich conditions. The experimentally observed morphology of the dendritic AlN crystals is characterized by the six-fold branches that developed outward within an Equatorial Plane and secondary dendrites that grew above and below the Equatorial Plane. The physical mechanisms that lead to the shape-controlled synthesis of AlN dendritic crystals were studied through experimental analysis and theoretical investigation including density functional theory (DFT) calculation and phase-field (PF) crystal growth modeling. Based on the DFT-calculated surface energy values, an energy minimization argument was used to construct the AlN nucleus. PF crystal growth modeling provides the details of the sequential crystallization process of the dendritic AlN crystals. The results of this study provide a complete understanding of the shape-controlled growth of AlN crystals, which aids the rational growth design of AlN and other relevant compounds

Philippe Jetzer - One of the best experts on this subject based on the ideXlab platform.

  • bending angle of light in Equatorial Plane of kerr sen black hole
    Physics Letters B, 2018
    Co-Authors: Rashmi Uniyal, Hemwati Nandan, Philippe Jetzer
    Abstract:

    Abstract We study the gravitational lensing by a Kerr–Sen Black Hole arising in heterotic string theory. A closed form expression for the bending angle of light in Equatorial Plane of Kerr–Sen Black Hole is derived as a function of impact parameter, spin and charge of the Black Hole. Results obtained are also compared with the corresponding cases of Kerr Black Hole in general relativity. It is observed that charge parameter behaves qualitatively similar as the spin parameter for photons travelling in direct orbits while behaves differently for photons in retrograde orbits around Black Hole. As the numerical value of the Black Hole charge increases, bending angle becomes larger in strong field limit. Further it is observed that this effect is more pronounced in case of direct orbits in comparison to the retro orbits. For both the direct and retro motion, the bending angle exceeds 2π, which in turn results in multiple loops and formation of relativistic images.