ChemInform Abstract: A New Enantioselective Route to (+)‐Quebrachamine (I).

Asaoka, Morio; Takei, Hisashi

doi:10.1002/chin.198937355

Cited by 12 publications

(14 citation statements)

References 1 publication

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“…also Asaoka (1989); Cunningham (1998); Li et al (2005). Specializing further to the Schwarzschild metric limit by setting a = 0, with M = Ms c 2 for a source of mass Ms, one obtains from eqs.…”

Section: Killing Vector Approachmentioning

confidence: 99%

“…These include, for example, the interpretation of X-ray spectral distributions originating from black hole accretion disks (Asaoka 1989;Bromley et al 1998;Cunningham 1998;Fabian et al 2000;Fanton et al 1997;Laor 1991;Li et al 2005;Martocchia et al 2000), and the implementation of satellite navigational systems (Bahder 2003;Linet & Teyssandier 2002;Pascual-Sanchez 2007). Depending on the specific context, emphasis has to be placed on different aspects influencing the shift.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, in general one is forced to integrate the geodesic equations numerically, cf. Asaoka (1989); Fanton et al (1997);Laor (1991); Li et al (2005).…”

Section: Introductionmentioning

confidence: 99%

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On the Doppler effect for light from orbiting sources in Kerr-type metrics

Cisneros

Goedecke

Beetle

et al. 2015

Monthly Notices of the Royal Astronomical Society

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A formula is derived for the combined motional and gravitational Doppler effect in general stationary axisymmetric metrics for a photon emitted parallel or antiparallel to the assumed circular orbital motion of its source. The same formula is derived by both the eikonal approximation and Killing vector approaches to elucidate connections between observational astronomy and modern Relativity. The formula yields expected results in the limits of a moving or stationary source in the exterior Kerr and Schwarzschild metrics and is useful for broad range astrophysical analyses.

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Section: Killing Vector Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Doppler effect for light from orbiting sources in Kerr-type metrics

Cisneros

Goedecke

Beetle

et al. 2015

Monthly Notices of the Royal Astronomical Society

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“…The observed radiation flux is then obtained by integrating the intrinsic emission over the entire disc surface, from the inner edge (r = r in ) to the outer edge (r = r out ), weighted by the transfer function T (r e , φ e , θ o , a) determining the impact of relativistic energy change (Doppler and gravitational) as well as the lensing effect for a distant observer directed along the inclination angle θ o (see Cunningham 1975;Asaoka 1989;Karas et al 1992;Karas 2006).…”

Section: Black-hole Signatures In Accretion Disc Radiationmentioning

confidence: 99%

Role of emission angular directionality in spin determination of accreting black holes with a broad iron line

Svoboda¹,

Dovčiak²,

Goosmann³

et al. 2009

A&A

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Aims. The spin of an accreting black hole can be determined by spectroscopy of the emission and absorption features produced in the inner regions of an accretion disc. In this work, we discuss the method employing the relativistic line profiles of iron in the X-ray domain, where the emergent spectrum is blurred by general relativistic effects. Methods. Precision of the spectra fitting procedure could be compromised by inappropriate accounting for the angular distribution of the disc emission. Often a unique profile is assumed, invariable over the entire range of radii in the disc and energy in the spectral band. An isotropic distribution or a particular limb-darkening law have been frequently set, although some radiation transfer computations exhibit an emission excess towards the grazing angles (i.e., the limb brightening). By assuming a rotating black hole in the centre of an accretion disc, we perform radiation transfer computations of an X-ray irradiated disc atmosphere (NOAR code) to determine the directionality of outgoing X-rays in the 2−10 keV energy band. Based on these computations, we produce a new extension to the KY software package for X-ray spectra fitting of relativistic accretion discs. Results. We study how sensitive the spin determination is to the assumptions about the intrinsic angular distribution of the emitted photons. The uncertainty of the directional emission distribution translates to 20% uncertainty in the determination of the marginally stable orbit. We implemented the simulation results as a new extension to the KY software package for X-ray spectra fitting of relativistic accretion disc models. Although the parameter space is rather complex, leading to a rich variety of possible outcomes, we find that on average the isotropic directionality reproduces our model data to the best precision. Our results also suggest that an improper use of limb darkening can partly mimic a steeper profile of radial emissivity. We demonstrate these results in the case of XMM-Newton observation of the Seyfert galaxy MCG-6-30-15, for which we construct confidence levels of χ 2 statistics, and on the simulated data for the future X-ray IXO mission. Our simulations, with the tentative IXO response, show a significant improvement that can qualitatively enhance the accuracy of spin determination.

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“…'bound' material), moving with 4-velocity uj^ may be written as (see e.g. Asaoka, 1989;Laor et al, 1990;Kurpiewski & Jaroszyriski, 1999;Gierlinski et al, 2001): T{g,fio;r,,eMfdr'dO'dg (6.3) Here, || J|P is the azimuthal average of the square of the 4-cmrent density, T{g, //(,; fg, de)…”

Section: Calculating the Observed Spectrummentioning

confidence: 99%

Observational Effects of Strong gravity

Beckwith

Done

2005

Astrophys Space Sci

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source• a link is made to the metadata record in Durham E-Theses• the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. AbstractIt is now a century since Einstein tore down the edifice of classical physics, ultimately replacing it with his crowning achievement, the General Theory of Relativity, the most remarkable prediction of which is the black hole. There are many astrophysical examples of black holes, understanding which has long been a goal of high-energy astronomy. We review how these observations can be explained in terms of a two-phase accretion flow.Hard X-ray photons produced in an optically thin gas are reflected from a cool accretion disk, resulting in a complex reflection spectra, which are dominated by a narrow IronKa fluorescence feature at 6.4 keV (dependent on the ionisation state of the cool disk).The photons that form this spectral feature originate in rapidly moving material, close to the black event horizon. They are therefore subject to the combined dynamical effects of the accretion disk and those of General Relativity, resulting in a highly broadened line profile. The observed form of the line can then, in principle, be used as a test of the strong gravitational field of the black hole.We have developed a new, extremely fast strong gravity code that accurately calculates the effect of strong gravity on photons originating close to the black hole event horizon, including the ability to calculate the trajectories of photons that perform multiple orbits of the black hole. We compare results from the code to the standard models describing relativistic smeared lines available to the commimity, finding that they match to within < 5%. We apply this code to the observed shape of the Iron Ka line and show that the (poorly understood) vertical structure of the accretion disk strongly affects the derived radial emissivity profile, which has important consequences for the interpretation of observational data.Following on from this, we consider the spectral and imaging properties of thin Keplerian accretion disks, fully including the effects of photons that perform midtiple orbits of the black hole. Viewed at high inchnations, these photons can carry as much as ~ 60% of the total luminosity of the system, which returns to the disk at a range of radii. At low inclinations, the multiple orbit photons re-intercept the disk plane close to the black hole.For a Schwarzschild black hole, this lies within the plunging region and so the photons need not be absorbed by the disk. The resultant ring is bright it may well be possible to use these as a future test of strong gravity via X-ray interferometric images of accreting black holes.

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ChemInform Abstract: A New Enantioselective Route to (+)‐Quebrachamine (I).

Cited by 12 publications

References 1 publication

On the Doppler effect for light from orbiting sources in Kerr-type metrics

On the Doppler effect for light from orbiting sources in Kerr-type metrics

Role of emission angular directionality in spin determination of accreting black holes with a broad iron line

Observational Effects of Strong gravity

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