Elemental abundances in the upper solar atmosphere

Feldman, U.

doi:10.1088/0031-8949/46/3/002

Cited by 538 publications

(538 citation statements)

References 51 publications

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“…In addition, we used the same photoelectric cross-sections by Balucinska-Church & McCammon (1992) used in the cited works. We also tried other solar abundances (Feldman (1992); Wilms et al (2000); Lodders (2003) and Asplund et al (2009)) and in all cases the 1+2BB model showed a similar statistical predominance in comparision to the PL+BB and the 2BB models as described above.…”

Section: Phase-average Analysismentioning

confidence: 90%

The outburst decay of the low magnetic field magnetar SWIFT J1822.3−1606: phase-resolved analysis and evidence for a variable cyclotron feature

Castillo

Israel

Tiengo

et al. 2016

Mon. Not. R. Astron. Soc.

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Section: Phase-average Analysismentioning

confidence: 90%

The outburst decay of the low magnetic field magnetar SWIFT J1822.3−1606: phase-resolved analysis and evidence for a variable cyclotron feature

Castillo

Israel

Tiengo

et al. 2016

Mon. Not. R. Astron. Soc.

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“…The instrumental background was subtracted from themand the sky background was modeled with the sum of an unabsorbed thermal component (APEC; Smith et al 2001) describing emission from the Local Hot Bubble (LHB), an absorbed thermal component describing emission from the Galactic Halo (GH), and an absorbed powerlaw component describing emission from unresolved point sources. We used photoelectric absorption cross-sections from Verner et al (1996)and the elemental abundances from Feldman (1992). The hydrogen column density in the direction of MACSJ0717.5+3745 was fixed to8.4 10 20 cm −2 , which is the sum of the weighted average atomic hydrogen column density from the Leiden-Argentine-Bonn (Kalberla et al 2005) Survey and the molecular hydrogen column density determined by Willingale et al (2013) from Swift data.…”

Section: Chandra Background Modelingmentioning

confidence: 99%

Chandra and JVLA Observations of HST Frontier Fields Cluster MACS J0717.5+3745

Weeren

Ogrean

Jones

et al. 2017

ApJ

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To investigate the relationship between thermal and non-thermal components in merger galaxy clusters, we present deep JVLA and Chandraobservations of the HST Frontier Fields cluster MACSJ0717.5+3745. The Chandraimage shows a complex merger event, with at least four components belonging to different merging subclusters. Northwestof the cluster, ∼0.7 Mpc from the center, there is a ram-pressure-stripped core that appears to have traversed the densest parts of the cluster after entering the intracluster medium (ICM) from the direction of a galaxy filament to the southeast. We detect a density discontinuity north-northeastof this core, which we speculate is associated with a cold front. Our radio images reveal new details for the complex radio relic and radio halo in this cluster. In addition, we discover several new filamentary radio sources with sizes of 100-300kpc. A few of these seem to be connected to the main radio relic, while others are either embedded within the radio halo or projected onto it. A narrow-angled-tailed (NAT) radio galaxy, a cluster member, is located at the center of the radio relic. The steep spectrum tails of this active galactic nucleuslead into the large radio relic where the radio spectrum flattens again. This morphological connection between the NAT radio galaxy and relic provides evidence for reacceleration (revival) of fossil electrons. The presence of hot 20 keV ICM gas detected by Chandranear the relic location provides additional support for this re-acceleration scenario.

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“…Red curve: Theoretical spectrum from CHIANTI with temperature equal to 0.90 keV. Abundances from the CHIANTI "coronal _ ext" (Feldman 1992) abundance set are assumed. …”

Section: Observationsmentioning

confidence: 99%

THE X-RAY LINE FEATURE AT 3.5 KeV IN GALAXY CLUSTER SPECTRA

Phillips

Sylwester

2015

ApJ

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Recent work by Bulbul et al. and Boyarsky et al. has suggested that a line feature at ∼3.5 keV in the X-ray spectra of galaxy clusters and individual galaxies seen with XMM-Newton is due to the decay of sterile neutrinos, a dark matter candidate. This identification has been criticized by Jeltema & Profumo on the grounds that model spectra suggest that atomic transitions in helium-like potassium (K XVIII) and chlorine (Cl XVI) are more likely to be the emitters. Here it is pointed out that the K XVIII lines have been observed in numerous solar flare spectra at high spectral resolution with the RESIK crystal spectrometer and also appear in Chandra HETG spectra of the coronally active star σ Gem. In addition, the solar flare spectra at least indicate a mean coronal potassium abundance, which is a factor between 9 and 11 higher than the solar photospheric abundance. This fact, together with the low statistical quality of the XMM-Newton spectra, completely account for the ∼3.5 keV feature and there is therefore no need to invoke a sterile neutrino interpretation of the observed line feature at ∼3.5 keV.

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Elemental abundances in the upper solar atmosphere

Cited by 538 publications

References 51 publications

The outburst decay of the low magnetic field magnetar SWIFT J1822.3−1606: phase-resolved analysis and evidence for a variable cyclotron feature

The outburst decay of the low magnetic field magnetar SWIFT J1822.3−1606: phase-resolved analysis and evidence for a variable cyclotron feature

Chandra and JVLA Observations of HST Frontier Fields Cluster MACS J0717.5+3745

THE X-RAY LINE FEATURE AT 3.5 KeV IN GALAXY CLUSTER SPECTRA

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