Electron-Ion Recombination Measurements Motivated by AGN X-Ray Absorption Features: Fe
                    <scp>xiv</scp>
                    Forming Fe
                    <scp>xiii</scp>

Schmidt, E. W.; Schippers, S.; Müller, Alfred; Lestinsky, M.; Sprenger, F.; Grieser, M.; Repnow, R.; Wolf, A.; Brandau, C.; Schnell, M.; Savin, D. W.

doi:10.1086/504038

Cited by 44 publications

(84 citation statements)

References 37 publications

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“…For earlier results, inaccuracies in the atomic data used also led to biased results, especially for Fe when the most recent di-electronic recombination rates were not used, as discussed by Netzer (2004). For instance, Schmidt et al (2006) and Nahar et al (2009) performed detailed atomic calculations of the di-electronic recombination rates. Schmidt et al (2004) measured the wavelengths of the O v lines, after Steenbrugge et al (2003) had noted that the wavelength used for the 22 Å line was likely to be wrong.…”

Section: Abundances From Narrow Absorption Linesmentioning

confidence: 99%

Multiwavelength campaign on Mrk 509

Steenbrugge

Kaastra

Detmers

et al. 2011

A&A

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Context. The study of abundances in the nucleus of active galaxies allows us to investigate the evolution of the abundance by comparing local and higher redshift galaxies. However, the methods used so far have substantial drawbacks or rather large uncertainties. Some of the measurements are at odds with the initial mass function derived from the older stellar population of local elliptical galaxies. Aims. We determine accurate and reliable abundances of C, N, Ne, and Fe relative to O from the narrow absorption lines observed in the X-ray spectra of Mrk 509. Methods. We use the stacked 600 ks XMM-Newton RGS and 180 ks Chandra LETGS spectra. Thanks to simultaneous observations with INTEGRAL and the optical monitor on-board XMM-Newton for the RGS observations and HST-COS and Swift for the LETGS observations, we have an individual spectral energy distribution for each dataset. Owing to the excellent quality of the RGS spectrum, the ionisation structure of the absorbing gas is well constrained, allowing for a reliable abundance determination using ions over the whole observed range of ionisation parameters. Results. We find that the relative abundances are consistent with the proto-solar abundance ratios: C/O = 1.19 ± 0.08, N/O = 0.98 ± 0.08, Ne/O = 1.11 ± 0.10, Mg/O = 0.68 ± 0.16, Si/O = 1.3 ± 0.6, Ca/O = 0.89 ± 0.25, and Fe/O = 0.85 ± 0.06, with the exception of S, which is slightly under-abundant, S/O = 0.57 ± 0.14. Our results, and their implications, are discussed and compared to the results obtained using other techniques to derive abundances in galaxies.

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Section: Abundances From Narrow Absorption Linesmentioning

confidence: 99%

Multiwavelength campaign on Mrk 509

Steenbrugge

Kaastra

Detmers

et al. 2011

A&A

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“…A factor of ∼1.5-3 is expected due to an experimental artifact (Gwinner et al 2000;Wolf & Gwinner 2003;Hörndl et al 2006). The remaining factor of ∼5.6-11.3 suggests the presence of unresolved near-zero eV DR resonances as has been seen for other systems (Uwira et al 1997;Savin et al 2002bSavin et al , 2003Schmidt et al 2006;Lestinsky et al 2009;Schippers et al 2011).…”

Section: +mentioning

confidence: 79%

“…Experimental studies of B-and Al-like ns 2 np systems have been performed for B-like Fe 21+ (Savin et al 2003) and Allike Fe 13+ (Schmidt et al 2006;Badnell 2006a) using the TSR Cooler. In both cases, good agreement was found between theory and experiment for ΔN = 0 DR.…”

Section: Discussion Of High-n Dr Via δN = 0 Core Excitationsmentioning

confidence: 99%

“…For Mg 7+ we used a scaling factor of 0.9903. The data reduction methods for deriving an experimental MBRRC have been discussed elsewhere in detail (Schippers et al , 2004Schmidt et al 2006;Lukić et al 2007;Lestinsky et al 2008). The total experimental uncertainty for the absolute MBRRC is estimated to be ±25% at a 90% confidence level, due primarily to the ion current calibration (Lampert et al 1996).…”

Section: Methodsmentioning

confidence: 99%

“…We derive the PRRC from our experimental MBRRC following the method laid out in detail in Schmidt et al (2006) and Lestinsky et al (2009). As was done in those works, .…”

Section: +mentioning

confidence: 99%

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ELECTRON-ION RECOMBINATION OF Mg^{6 +}FORMING Mg^{5 +}AND OF Mg^{7 +}FORMING Mg^{6 +}: LABORATORY MEASUREMENTS AND THEORETICAL CALCULATIONS

Lestinsky

Badnell

Bernhardt

et al. 2012

ApJ

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We have measured electron-ion recombination for C-like Mg 6+ forming Mg 5+ , and for B-like Mg 7+ forming Mg 6+ . These studies were performed using a merged electron-ion beam arrangement at the TSR heavy ion storage ring located in Heidelberg, Germany. Both primary ions have metastable levels with significant lifetimes. Using a simple cascade model we estimate the population fractions in these metastable levels. For the Mg 6+ results, we find that the majority of the stored ions are in a metastable level, while for Mg 7+ the metastable fraction is insignificant. We present the Mg 6+ merged beams recombination rate coefficient for DR via N = 2 → N = 2 core electron excitations (ΔN = 0 DR) and for Mg 7+ via 2 → 2 and 2 → 3 core excitations. Taking the estimated metastable populations into account, we compare our results to state-of-the-art multiconfiguration Breit-Pauli theoretical calculations. Significant differences are found at low energies where theory is known to be unreliable. Moreover, for both ions we observe a discrepancy between experiment and theory for ΔN = 0 DR involving capture into high-n Rydberg levels and where the stabilization is primarily due to a radiative transition of the excited core electron. This is consistent with previous DR experiments on M-shell iron ions which were performed at TSR. The large metastable content of the Mg 6+ ion beam precludes generating a plasma recombination rate coefficient (PRRC). However, this is not an issue for Mg 7+ and we present an experimentally derived Mg 7+ PRRC for plasma temperatures from 400 K to 10 7 K with an estimated uncertainty of less than 27% at a 90% confidence level. We also provide a fit to our experimentally derived PRRC for use in plasma modeling codes.

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Active Galactic Nuclei

Haas¹,

Biermann²,

Chini³

et al. 2007

Astron Nachr

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The idea: duringg ravitationalcollapsel ightmightbecreated insteado fg ravitationalwavesorotherformsof energy.Thisisqualitativelyjustified,sincesupernovaesimulationsaretoo faintcompared too bservationsand interferometerdetectionsof gravitationalwavesarewithout success upton ow.The talk presents some quantitativecalculations.But moreimportant:if lightiscreated insteadofgravitationalwavesthenitisachallenge to observationalastronomy(inconjunctionwithsimulations)togivesome experimentalevidenceforsuchaneffect arisingwithjets,supernovaeorgammabursts. ADirectComparison of the QSOSamplesfrom VPMS and SDSS F35HThe variability and propermotionsurvey(VPMS)isanefficientand alternativemethod forthe selectionofQSO candidatesw hichi snotexplicitlybased on apresumedspectrale nergydistribution. Weh avep erformedthe Tautenburg-CalarAltoVPMS withthe main aim tocreateadatabaseforthe studyof QSOlong-termvariability on ane xceptionallylong time-baselineofabout four decades.Inthiscontext,ahigh completeness of the QSO sampleisanimportantissue. Moreprecisely,the QSOsamplehastobefree of asubstantialvariability-induced bias.Thishasbeen checkedbythe directcomparison of the VPMS withthe SloanDigitalSkySurvey(SDSS) whichoverlapinthe field around M3whereVPMS hasidentified175QSOsascompared to75QSOslisted by SDSS DR5. The results from the detailedanalysisof bothsamplesconfirmthe high completeness of the VPMS. Asab y-product,wei dentifyanotheru nusualbroadabsorptionl ine( BAL)QSOwhichshows characteristic featuresof iron lowionizationBAL(FeLoBAL)QSOs.Withthe unusuallys trong compressionofthe UV,the absenceo fe missionl ines,a nd the presenceo faF IRST radiocounterpart,the objectr esemblest he unusual FeLoBALQSO VPMS J1342+2840.NotablybothQSOshavenotbeen selected bythe colour searchofSDSS. Thishighlights the possibility thatthe fractionofsuchunusualQSOsmightbesignificantlyhigherthanexpected.

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Electron-Ion Recombination Measurements Motivated by AGN X-Ray Absorption Features: Fe xiv Forming Fe xiii

Cited by 44 publications

References 37 publications

Multiwavelength campaign on Mrk 509

Multiwavelength campaign on Mrk 509

ELECTRON-ION RECOMBINATION OF Mg^{6 +}FORMING Mg^{5 +}AND OF Mg^{7 +}FORMING Mg^{6 +}: LABORATORY MEASUREMENTS AND THEORETICAL CALCULATIONS

Active Galactic Nuclei

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Electron-Ion Recombination Measurements Motivated by AGN X-Ray Absorption Features: Fe xiv Forming Fe xiii

Cited by 44 publications

References 37 publications

Multiwavelength campaign on Mrk 509

Multiwavelength campaign on Mrk 509

ELECTRON-ION RECOMBINATION OF Mg6 +FORMING Mg5 +AND OF Mg7 +FORMING Mg6 +: LABORATORY MEASUREMENTS AND THEORETICAL CALCULATIONS

Active Galactic Nuclei

Contact Info

Product

Resources

About

ELECTRON-ION RECOMBINATION OF Mg^{6 +}FORMING Mg^{5 +}AND OF Mg^{7 +}FORMING Mg^{6 +}: LABORATORY MEASUREMENTS AND THEORETICAL CALCULATIONS