Charge Transfer Reactions

Dennerl, K.

doi:10.1007/s11214-010-9720-5

Cited by 101 publications

(64 citation statements)

References 234 publications

(231 reference statements)

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“…Astronomical CX X-rays were first discovered in near-Earth comets (Lisse et al 1996) and now the related detections have been expanded to various types of objects, from neighboring planets to distant galaxy clusters (see the review by Dennerl et al 2010). A qualitative discussion on the possible CX lines near 3.5 keV was presented in BU14.…”

Section: Introductionmentioning

confidence: 99%

A novel scenario for the possible X-ray line feature at ~3.5 keV

Kaastra

Raassen

et al. 2015

A&A

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Motivated by recent claims of a compelling ∼3.5 keV emission line from nearby galaxies and galaxy clusters, we investigate a novel plasma model incorporating a charge exchange component obtained from theoretical scattering calculations. Fitting this kind of component with a standard thermal model yields positive residuals around 3.5 keV, produced mostly by S xvi transitions from principal quantum numbers n ≥ 9 to the ground. Such high-n states can only be populated by the charge exchange process. In this scenario, the observed 3.5 keV line flux in clusters can be naturally explained by an interaction in an effective volume of ∼1 kpc 3 between a ∼3 keV temperature plasma and cold dense clouds moving at a few hundred keV −1 . The S xvi lines at ∼3.5 keV also provide a unique diagnostic of the charge exchange phenomenon in hot cosmic plasmas.

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Section: Introductionmentioning

confidence: 99%

A novel scenario for the possible X-ray line feature at ~3.5 keV

Kaastra

Raassen

et al. 2015

A&A

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“…The X-ray emission common to all those objects is produced from the radiative de-excitation of highly-charged solar wind (SW) ions that have captured an electron from neutral particles encountered in these environments, and is accordingly named solar wind charge exchange (SWCX) X-ray emission. A thorough review of SWCX emission in the solar system is given in Bhardwaj (2010) and Dennerl (2010).…”

Section: Introductionmentioning

confidence: 99%

Solar wind charge exchange X-ray emission from Mars

Koutroumpa¹,

Modolo²,

Chanteur³

et al. 2012

A&A

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Aims. We study the soft X-ray emission induced by charge exchange (CX) collisions between solar-wind, highly charged ions and neutral atoms of the Martian exosphere. Methods. A 3D multispecies hybrid simulation model with improved spatial resolution (130 km) is used to describe the interaction between the solar wind and the Martian neutrals. We calculated velocity and density distributions of the solar wind plasma in the Martian environment with realistic planetary ions description, using spherically symmetric exospheric H and O profiles. Following that, a 3D test-particle model was developed to compute the X-ray emission produced by CX collisions between neutrals and solar wind minor ions. The model results are compared to XMM-Newton observations of Mars. Results. We calculate projected X-ray emission maps for the XMM-Newton observing conditions and demonstrate how the X-ray emission reflects the Martian electromagnetic structure in accordance with the observed X-ray images. Our maps confirm that X-ray images are a powerful tool for the study of solar wind-planetary interfaces. However, the simulation results reveal several quantitative discrepancies compared to the observations. Typical solar wind and neutral coronae conditions corresponding to the 2003 observation period of Mars cannot reproduce the high luminosity or the corresponding very extended halo observed with XMM-Newton. Potential explanations of these discrepancies are discussed.

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“…An upper limit of the Xray luminosity produced by charge transfer reactions can be computed from the following relation (Dennerl 2010):…”

Section: Charge Transfer Processesmentioning

confidence: 99%

Chandra ACIS-S imaging spectroscopy of anomalously faint X-ray emission from Comet 103P/Hartley 2 during the EPOXI encounter

Lisse

Christian

Wolk

et al. 2013

Icarus

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The planetary nebula (PN) A 30 is believed to have undergone a very late thermal pulse resulting in the ejection of knots of hydrogen-poor material. Using multi-epoch HST images we have detected the angular expansion of these knots and derived an age of 850 +280 −150 yr. To investigate the spectral and spatial properties of the soft X-ray emission detected by ROSAT, we have obtained Chandra and XMM-Newton deep observations of A 30. The X-ray emission from A 30 can be separated into two components: a point-source at the central star and diffuse emission associated with the hydrogen-poor knots and the cloverleaf structure inside the nebular shell. To help us assess the role of the current stellar wind in powering this X-ray emission, we have determined the stellar parameters and wind properties of the central star of A 30 using a non-LTE model fit to its optical and UV spectrum. The spatial distribution and spectral properties of the diffuse X-ray emission is highly suggestive that it is generated by the post-born-again and present fast stellar winds interacting with the hydrogen-poor ejecta of the born-again event. This emission can be attributed to shock-heated plasma, as the hydrogen-poor knots are ablated by the stellar winds, under which circumstances the efficient mass-loading of the present fast stellar wind raises its density and damps its velocity to produce the observed diffuse soft X-rays. Charge transfer reactions between the ions of the stellar winds and material of the born-again ejecta has also been considered as a possible mechanism for the production of diffuse X-ray emission, and upper limits on the expected X-ray production by this mechanism have been derived. The origin of the X-ray emission from the central star of A 30 is puzzling: shocks in the present fast stellar wind and photospheric emission can be ruled out, while the development of a new, compact hot bubble confining the fast stellar wind seems implausible.

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Charge Transfer Reactions

Cited by 101 publications

References 234 publications

A novel scenario for the possible X-ray line feature at ~3.5 keV

A novel scenario for the possible X-ray line feature at ~3.5 keV

Solar wind charge exchange X-ray emission from Mars

Chandra ACIS-S imaging spectroscopy of anomalously faint X-ray emission from Comet 103P/Hartley 2 during the EPOXI encounter

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