Laboratory Measurements and Identification of the Fe
                    <scp>xviii</scp>
                    –
                    <scp>xxiv</scp>
                    L‐Shell X‐Ray Line Emission

Brown, G. V.; Beiersdörfer, P.; Liedahl, D. A.; Widmann, K.; Kahn, S. M.; Clothiaux, E. J.

doi:10.1086/339374

Cited by 93 publications

(98 citation statements)

References 38 publications

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“…Decay rates and oscillator strengths calculated with HULLAC may be inaccurate by as much as $20%, and the wavelengths are accurate to within $50 mÅ . For the strong Fe L resonance lines, we use laboratory transition wavelength measurements of Brown et al (2002). We also use values published by Pradhan (2000) for the strong O vi inner-shell absorption-line properties.…”

Section: Explicit Test Of the Lee Et Al (2001) Modelmentioning

confidence: 99%

Can a Dusty Warm Absorber Model Reproduce the Soft X‐Ray Spectra of MCG −6‐30‐15 and Markarian 766?

Šako¹,

Kahn²,

Branduardi‐Raymont³

et al. 2003

ApJ

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XMM-Newton RGS spectra of MCG À6-30-15 and Mrk 766 exhibit complex discrete structure, which was interpreted in a paper by Branduardi-Raymont and coworkers as evidence for the existence of relativistically broadened Ly emission from carbon, nitrogen, and oxygen, produced in the innermost regions of an accretion disk around a Kerr black hole. This suggestion was subsequently criticized in a paper by Lee and coworkers, who argued that for MCG À6-30-15, the Chandra HETG spectrum, which is partially overlapping the RGS in spectral coverage, is adequately fitted by a dusty warm absorber model, with no relativistic line emission. We present a reanalysis of the original RGS data sets in terms of the model by Lee and coworkers. Specifically, we show that (1) the explicit model given by Lee and coworkers differs markedly from the RGS data, especially at longer wavelengths, beyond the region sampled by the HETG; (2) generalizations of the Lee and coworkers model, with all parameters left free, do provide qualitatively better fits to the RGS data, but are still incompatible with the detailed spectral structure; (3) the ionized oxygen absorption-line equivalent widths are well measured with the RGS for both sources, and place very tight constraints on both the column densities and turbulent velocity widths of O vii and O viii. The derived column densities are well below those posited by Lee and coworkers and are insufficient to play any role in explaining the observed edge-like feature near 17.5 Å ; (4) the lack of a significant neutral oxygen edge near 23 Å places very strong limits on any possible contribution of absorption to the observed structure by dust embedded in a warm medium; and (5) the original relativistic line model with warm absorption proposed by BranduardiRaymont and coworkers provides a superior fit to the RGS data, both in the overall shape of the spectrum and in the discrete absorption lines. We also discuss a possible theoretical interpretation for the putative relativistic Ly line emission in terms of the photoionized surface layers of the inner regions of an accretion disk. While there are still a number of outstanding theoretical questions about the viability of such a model, it is interesting to note that simple estimates of key parameters are roughly compatible with those derived from the observed spectra.

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Section: Explicit Test Of the Lee Et Al (2001) Modelmentioning

confidence: 99%

Can a Dusty Warm Absorber Model Reproduce the Soft X‐Ray Spectra of MCG −6‐30‐15 and Markarian 766?

Šako¹,

Kahn²,

Branduardi‐Raymont³

et al. 2003

ApJ

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“…Feature B is the result of a single Fe xvi line, the transition 1s 2 2s 2 2p 1/2 2p 4 3/2 3s 1/2 3d 5/2 (J = 3/2) → 1s 2 2s 2 2p 2 1/2 2p 4 3/2 3s 1/2 (J = 1/2) at 15.110 Å. It is weakly blended with an Fe xix line, which Brown et al (2002) place at 15.079 ± 4 Å. This line is the closest to a true dielectronic satellite line in the Fe xvii L-shell spectrum; unfortunately, it is formed by an almost equal mixture of collisional and dielectronic excitation.…”

Section: Identification Of N = 3 Dielectronic Satellite Lines In the mentioning

confidence: 97%

“…It was given by Brown et al (2002) as 15.198 ± 0.005 Å, and the fit by Gu et al (2006) and Gu (2009) The inclusion of the Fe xvi lines improves the fit of the Capella spectrum at the location of features B and D. Feature D is the result of a collisionally excited Fe xvi line, as discussed earlier by Beiersdorfer et al (2012). Feature B is the result of a single Fe xvi line, the transition 1s 2 2s 2 2p 1/2 2p 4 3/2 3s 1/2 3d 5/2 (J = 3/2) → 1s 2 2s 2 2p 2 1/2 2p 4 3/2 3s 1/2 (J = 1/2) at 15.110 Å.…”

Section: Identification Of N = 3 Dielectronic Satellite Lines In the mentioning

confidence: 99%

L-SHELL DIELECTRONIC SATELLITE TRANSITIONS OF Fe XVII

Beiersdörfer

Bode

Ishikawa

et al. 2014

ApJ

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We have used the relativistic multi-reference Møller-Plesset perturbation theory to calculate the positions of the dielectronic satellite transitions involving doubly excited 3 3 configurations that are associated with the X-ray spectrum of Fe xvii. A comparison of these positions with the wavelengths employed in astrophysical modeling codes shows discrepancies of up to 36 mÅ. Inspection of the spectrum of Capella recorded with the high energy transmission grating on the Chandra X-Ray Observatory reveals several features enhanced by Fe xvi lines formed by dielectronic recombination, one of which may be of future diagnostic use as it is fairly well isolated and in large part formed by dielectronic recombination.

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“…We are continuing such measurements on the Livermore electron beam ion traps. In addition, we are studying complete spectra in a given wavelength range, such as the L-shell spectra of Si, S, Ar, and Fe in the EUV or x-ray range [58,59,60], as discussed by J. K. Lepson in this volume.…”

Section: Isoelectronic Trends Of Complex Ionsmentioning

confidence: 99%

Highly Charged Ion Research at the Livermore Electron Beam Ion Traps

Beiersdörfer

2005

Phys. Scr.

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Spectroscopy performed with the three Livermore electron beam ion traps is reviewed, which is continuing and complementing the innumerable contributions to atomic physics provided over the years by heavy-ion accelerators. Numerous spectrometers were developed that cover the spectral bands from the visible to the hard x ray region. These enabled exhaustive line surveys useful for x-ray astrophysics and for systematic studies along iso-electronic sequences, such as the 4s-4p, 3s-3p, and 2s-2p transitions in ions of the Cu-I, Na-I, and Li-I sequences useful for studying QED and correlation effects as well as for precise determinations of atomic-nuclear interactions. They also enabled measurements of radiative transition probabilities of very long-lived (milli-and microseconds) and very short-live (femtosecond) levels. Because line excitation processes can be controlled by choice of the electron beam energy, the observed line intensities are used to infer cross sections for electron-impact excitation, dielectronic recombination, resonance excitation, and innershell ionization. These capabilities have recently been expanded to simulate x-ray emission from comets by charge exchange. Specific contributions to basic atomic physics, nuclear physics, and high-temperature diagnostics are illustrated.

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Laboratory Measurements and Identification of the Fe xviii – xxiv L‐Shell X‐Ray Line Emission

Cited by 93 publications

References 38 publications

Can a Dusty Warm Absorber Model Reproduce the Soft X‐Ray Spectra of MCG −6‐30‐15 and Markarian 766?

Can a Dusty Warm Absorber Model Reproduce the Soft X‐Ray Spectra of MCG −6‐30‐15 and Markarian 766?

L-SHELL DIELECTRONIC SATELLITE TRANSITIONS OF Fe XVII

Highly Charged Ion Research at the Livermore Electron Beam Ion Traps

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