YOHKOH Observations of Fe XXVI X-Ray Line Emission from Solar Flares

Pike, C. D.; Phillips, K. J. H.; Lang, J.; Sterling, Alphonse C.; Watanabe, Tetsuya; Hiei, E.; Culhane, J. L.; Cornille, M.; Dubau, J.

doi:10.1086/177338

Cited by 40 publications

(30 citation statements)

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“…We identified the lower and higher energy lines with Fe xxv(r) and Fe xxvi Lyα emission respectively. The expected energy for the Fe xxv(r) line is 6.700 keV 7 , and that for the Fe xxvi Lyα line is 6.966 keV (Pike et al 1996). It can be seen from Table 2 Table 2).…”

Section: Fe XXV and Fe Xxvi Emission Linesmentioning

confidence: 79%

No signatures of black hole spin in the X-ray spectrum of the Seyfert 1 galaxy Fairall 9

Yaqoob

Turner

Tatum

et al. 2016

Mon. Not. R. Astron. Soc.

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Fairall 9 is one of several type 1 active galactic nuclei for which it has been claimed that the angular momentum (or spin) of the supermassive black hole can be robustly measured, using the Fe Kα emission line and Compton-reflection continuum in the X-ray spectrum. The method rests upon the interpretation of the Fe Kα line profile and associated Compton-reflection continuum in terms of relativistic broadening in the strong gravity regime in the innermost regions of an accretion disc, within a few gravitational radii of the black hole. Here, we re-examine a Suzaku X-ray spectrum of Fairall 9 and show that a face-on toroidal X-ray reprocessor model involving only nonrelativistic and mundane physics provides an excellent fit to the data. The Fe Kα line emission and Compton reflection continuum are calculated self-consistently, the iron abundance is solar, and an equatorial column density of ∼ 10 24 cm −2 is inferred. In this scenario, neither the Fe Kα line, nor the Compton-reflection continuum provide any information on the black-hole spin. Whereas previous analyses have assumed an infinite column density for the distant-matter reprocessor, the shape of the reflection spectrum from matter with a finite column density eliminates the need for a relativistically broadened Fe Kα line. We find a 90 per cent confidence range in the Fe Kα line FWHM of 1895-6205 km s −1 , corresponding to a distance of ∼ 3100 to 33, 380 gravitational radii from the black hole, or 0.015-0.49 pc for a black-hole mass of ∼ 1 − 3 × 10 8 M ⊙ .

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Section: Fe XXV and Fe Xxvi Emission Linesmentioning

confidence: 79%

No signatures of black hole spin in the X-ray spectrum of the Seyfert 1 galaxy Fairall 9

Yaqoob

Turner

Tatum

et al. 2016

Mon. Not. R. Astron. Soc.

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“…Spectral lines decaying from doubly excited helium-like ions are essential in understanding the dielectronic recombination process of hydrogen-like ions. The lines that appear as hydrogen-like satellites are often observed in astrophysical plasmas, and the hydrogen-like satellite-to-resonance intensities can be used to measure electron temperatures in solar flares (Dubau et al 1981;Parmar et al 1981;Tanaka 1986;Pike et al 1996). Furthermore, the high-n dielectronic recombination from the hydrogen-like ions can significantly affect some helium-like line ratios from low-lying (n = 2) transitions (Smith et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Energy levels and transition rates for helium-like ions withZ = 10–36

Guo

Wang

et al. 2016

A&A

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Aims. Helium-like ions provide an important X-ray spectral diagnostics in astrophysical and high-temperature fusion plasmas. An interpretation of the observed spectra provides information on temperature, density, and chemical compositions of the plasma. Such an analysis requires information for a wide range of atomic parameters, including energy levels and transition rates. Our aim is to provide a set of accurate energy levels and transition rates for helium-like ions with Z = 10-36. Methods. The second-order many-body perturbation theory (MBPT) was adopted in this paper. To support our MBPT results, we performed an independent calculation using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Results. We provide accurate energies for the lowest singly excited 70 levels among 1snl (n ≤ 6, l ≤ (n − 1)) configurations and the lowest doubly excited 250 levels arising from the K-vacancy 2ln l (n ≤ 6, l ≤ (n − 1)) configurations of helium-like ions with Z = 10−36. Wavelengths, transition rates, oscillator strengths, and line strengths are calculated for the E1, M1, E2, and M2 transitions among these levels. The radiative lifetimes are reported for all the calculated levels. Conclusions. Our MBPT results for singly excited n ≤ 2 levels show excellent agreement with other elaborate calculations, while those for singly excited n ≥ 3 and doubly excited levels show significant improvements over previous theoretical results. Our results will be very helpful for astrophysical line identification and plasma diagnostics.

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“…Note that the local ionization state in the vicinity of the hotspot may not necessarily be the same as the ionization state of the entire accretion disk. The rest energy of Fe K line emission must be some value between 6.404 keV (Fe i; see Bambynek et al 1972) and 6.966 keV (Fe xxvi; see Pike et al 1996). This corresponds to an uncertainty of ±4.2% in the measurement of g for the average rest-energy value in this range.…”

Section: Hotspot Fe K Line Measurement Uncertaintiesmentioning

confidence: 99%

On the Prospect of Constraining Black Hole Spin Through X-Ray Spectroscopy of Hotspots

Murphy

Yaqoob

Karas

et al. 2009

ApJ

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Future X-ray instrumentation is expected to allow us to significantly improve the constraints derived from the Fe K lines in active galactic nuclei, such as the black hole angular momentum (spin) and the inclination angle of the putative accretion disk. We consider the possibility that measurements of the persistent, timeaveraged Fe K line emission from the disk could be supplemented by the observation of a localized flare, or "hotspot," orbiting close to the black hole. Although observationally challenging, such measurements would recover some of the information loss that is inherent to the radially integrated line profiles. We present calculations for this scenario to assess the extent to which, in principle, black hole spin may be measured. We quantify the feasibility of this approach using realistic assumptions about likely measurement uncertainties.

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YOHKOH Observations of Fe XXVI X-Ray Line Emission from Solar Flares

Cited by 40 publications

References 0 publications

No signatures of black hole spin in the X-ray spectrum of the Seyfert 1 galaxy Fairall 9

No signatures of black hole spin in the X-ray spectrum of the Seyfert 1 galaxy Fairall 9

Energy levels and transition rates for helium-like ions withZ = 10–36

On the Prospect of Constraining Black Hole Spin Through X-Ray Spectroscopy of Hotspots

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