The iron Kα lines as a tool for magnetic field estimations in non-flat accretion flows

John, Z. G.; Bao, Y. Y.

doi:10.1016/j.newast.2004.06.004

Cited by 15 publications

(8 citation statements)

References 136 publications

(148 reference statements)

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“…However, instead of solving the shadow formation problem by numerical simulations, one can use the approach developed by Zakharov (1994bZakharov ( , 1995; Zakharov & Repin (1999, 2002a,b, 2004a, 2003bZakharov et al (2004);Zakharov (2004);Zakharov & Repin (2005a), Zakharov et al (2005a,b). Mirages are boundaries of bright images, and shadows are also generated for accretion disks.…”

Section: Searches For Mirages Near Sgr a * With Radioastronmentioning

confidence: 99%

Direct measurements of black hole charge with future astrometrical missions

Zakharov¹,

Paolis²,

Ingrosso³

et al. 2005

A&A

116

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Recently, Zakharov et al. (2005a, New Astron., 10, 479) considered the possibility of evaluating the spin parameter and the inclination angle for Kerr black holes in nearby galactic centers by using future advanced astrometrical instruments. A similar approach which uses the characteristic properties of gravitational retro-lensing images can be followed to measure the charge of a Reissner-Nordström black hole. Indeed, in spite of the fact that their formation might be problematic, charged black holes are objects of intensive investigations. From a theoretical point of view, it is well-known that a black hole is described by only three parameters, namely, its mass M, angular momentum J, and charge Q. Therefore, it would be important to have a method for measuring all these parameters, preferably by independent model of any. In this paper, we propose a procedure to measure the black hole charge by using the size of the retro-lensing images that can be revealed by future astrometrical missions. A discussion of the Kerr-Newmann black hole case is also offered.

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Section: Searches For Mirages Near Sgr a * With Radioastronmentioning

confidence: 99%

Direct measurements of black hole charge with future astrometrical missions

Zakharov¹,

Paolis²,

Ingrosso³

et al. 2005

A&A

116

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“…Even if we consider a supermassive black hole in the center of the quasar M SMBH = 10 9 M , then its Schwarzschild radius is r g = 3× 10 14 cm and assuming that the emission region for the X-ray radiation is located near the black hole r emission < 100 r g = 3 × † Simulations of X-ray line profiles are presented in a number of papers, see, for example, Zakharov & Repin (2002a,b,c,d, 2003a, 2003c) and references therein, in particular Zakharov et al (2003) showed that an information about magnetic filed may be extracted from X-ray line shape analysis; Zakharov & Repin (2003b) discussed signatures of X-ray line shapes for highly inclined accretion disks, Zakharov et al (2004a) calculated shapes of spectral lines for non-flat accretion flows. 10 16 cm, we obtain that r emission < R EC , therefore the point size source approximation can be adopted for the X-ray emitting region.…”

Section: Cosmological Distribution Of Microlensesmentioning

confidence: 99%

Contribution of Microlensing to X-ray Variability of Distant QSOs

Popovic

Jovanović

2004

Proc. IAU

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Abstract. We consider a contribution of microlensing to the X-ray variability of high-redshifted QSOs. Cosmologically distributed gravitational microlenses could be localized in galaxies (or even in bulge or halo of gravitational macrolenses) or could be distributed in a uniform way. We have analyzed both cases of such distributions. We found that the optical depth for gravitational microlensing caused by cosmologically distributed deflectors could be significant and could reach 10 −2 − 0.1 at z ∼ 2. This means that cosmologically distributed deflectors may contribute significantlly to the X-ray variability of high-redshifted QSOs (z > 2). Considering that the upper limit of the optical depth (τ ∼ 0.1) corresponds to the case where dark matter forms cosmologically distributed deflectors, observations of the X-ray variations of unlensed QSOs can be used for the estimation of the dark matter fraction of microlenses.

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“…The new Penning-trap experiment at the MPIK in Heidelberg, called ALPHATRAP [34], primarily aims at the g factor of heavy few-electron ions, including boronlike.Since the discovery of the quadratic Zeeman effect [35,36] numerous experimental studies in atoms and molecules have been accomplished [37][38][39][40]. The nonlinear Zeeman effect is important in astrophysics due to the strong magnetic field at the stellar objects [41][42][43]. It is also relevant for atomic clocks, magnetometers and other high-precision experimental setups as a source of the 2 P J fine structure J = 1/2 J = 3/2 Zeeman splitting 1st order M J = −1/2 M J = +1/2 M J = −3/2 M J = −1/2 M J = +1/2…”

mentioning

confidence: 99%

Interelectronic-interaction contribution to the nonlinear Zeeman effect in boronlike ions

et al. 2018

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Relativistic calculations of the second-and third-order contributions in magnetic field to the Zeeman splitting in boronlike ions are presented for the wide range of nuclear charge numbers Z = 6-92. The interelectronic-interaction correction of the first order in 1/Z is evaluated to all orders in αZ. The higherorder corrections in 1/Z are taken into account approximately by means of effective screening potentials.The obtained results are important for interpretation of experimental data on the Zeeman splitting in boronlike ions, in particular, for the ARTEMIS experiment presently implemented at GSI. 32.60.+i Investigations of the g factor of highly charged ions can serve for stringent tests of the boundstate QED, the determination of fundamental constants and of nuclear parameters, see, e.g., Refs.[1-4]. Meanwhile, the precision of the g-factor measurements in Penning traps has reached the level of 10 −9 -10 −11 [1,[5][6][7][8][9][10]. Achievement of the comparable theoretical accuracy requires consideration of the QED diagrams up to the second order in α, higher-order correlation contributions, and various nuclear effects, see Ref.[4] and more recent works [11][12][13][14][15][16][17]. The long-term combined experimental and theoretical efforts have provided the most accurate up-to-date value of the electron mass [18][19][20]. Recent measurement for two lithium-like calcium isotopes [21] is sensitive to the relativistic nuclear recoil effect indicating the potential to access bound-state QED effects beyond the Furry picture [14,15]. Further investigations with few-electron ions can provide an independent determination of the fine structure constant [22][23][24].The nonlinear effects in magnetic field play an important role in boronlike ions [25,26]. Due to the mirror symmetry, the second-order effect does not influence the ground-state Zeeman splitting in hydrogenlike, lithiumlike, and boronlike ions. However, it becomes observable in the Zeeman splitting of the 2 P 3/2 state of boronlike ions, which can be measured by the laser-microwave double-resonance spectroscopy [25,27]. Moreover, the quadratic effect gives a tiny correction to the fine-structure transition energies, which are measured with an increasing precision [28][29][30][31].The third-order effect contributes to the Zeeman splitting of any state, although in hydrogenlike and lithiumlike ions it is negligible at the present level of accuracy. In boronlike ions the nonlinear contributions are strongly enhanced due to the mixing of the fine-structure components.The first high-precision g-factor measurement in boronlike ion was performed for Ar 13+ at the MPIK with the laser spectroscopy [32]. The ARTEMIS experiment at GSI implements the laser-microwave double-resonance technique to reach the ppb precision for the g factors of the ground 2 P 1/2 and the first excited 2 P 3/2 states in boronlike argon [25,33]. The new Penning-trap experiment at the MPIK in Heidelberg, called ALPHATRAP [34], primarily aims at the g factor of heavy few-electron ions, inc...

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The iron Kα lines as a tool for magnetic field estimations in non-flat accretion flows

Cited by 15 publications

References 136 publications

Direct measurements of black hole charge with future astrometrical missions

Direct measurements of black hole charge with future astrometrical missions

Contribution of Microlensing to X-ray Variability of Distant QSOs

Interelectronic-interaction contribution to the nonlinear Zeeman effect in boronlike ions

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