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A magnetic cycle of τ Bootis? The coronal and chromospheric view
Schmitt, J. H. M. M.; Günther, H. M.; Poppenhaeger, K.
τ Bootis is a late F-type main sequence star orbited by a Hot Jupiter. During the last years spectropolarimetric observations led to the hypothesis that this star may host a global magnetic field that switches its polarity once per year, indicating a very short activity cycle of only one year duration. In our ongoing observational campaign, we hav…
Spectroscopic evidence of charge exchange X-ray emission from galaxies
Wang, Q. D.; Liu, J.
What are the origins of the soft X-ray line emission from non-AGN galaxies? XMM-Newton RGS spectra of nearby non-AGN galaxies (including starforming ones: M82, NGC 253, M51, M83, M61, NGC 4631, M94, NGC 2903, and the Antennae galaxies, as well as the inner bulge of M31) have been analyzed. In particular, the K\alpha triplet of O VII shows that the…
CSS091109:035759+102943: A candidate polar
Schwope, A. D.; Thinius, B.
We report optical time-resolved photometry of the CRTS transient CSS091109:035759+102943. Pronounced orbital variability with a 114 min period, large X-ray variability and the IR to X-ray spectral energy distribution suggest a classification as a magnetic cataclysmic binary, a likely AM Herculis star or polar.
Exospheric solar wind charge exchange as seen by XMM-Newton
Read, A. M.; Carter, J. A.; Semba, S.
We review a selection of recent papers describing solar wind charge exchange emission occurring in the Earth's exosphere as seen by the X-ray observatory XMM-Newton. We discuss the detection of this emission, the occurrence with respect to the solar cycle and solar activity, and various spectral signatures observed. We also describe a model develo…
Ion-ion charge exchange and X-rays from the winds of hot stars
Pollock, A. M. T.
Charge exchange occurs between charged ions with enough energy to overcome Coulomb repulsion, a condition satisfied for collisions at velocities like those of the winds driven from hot stars by radiation pressure. X-ray line ratios in some hot stars are inconsistent with those expected from thermal plasmas excited by electron impact. Ion-ion inter…
On the soft X-ray emission of M82
Mao, S.; Wang, Q. D.; Liu, J.
We present a spatial analysis of the soft X-ray and Hα emissions from the outflow of the starburst galaxy M82. We find that the two emissions are tightly correlated on various scales. The O VII triplet of M82, as resolved by X-ray grating observations of XMM-Newton, is dominated by the forbidden line, inconsistent with the thermal prediction. The …
Charge-exchange emission in the starburst galaxies M82 and NGC3256
Ranalli , P.
Charge-exchange (CE) emission produces features which are detectable with the current X-ray instrumentation in the brightest near galaxies. We describe these aspects in the observed X-ray spectra of the star forming galaxies M82 and NGC 3256, from the Suzaku and XMM-Newton telescopes. Emission from both ions (O, C) and neutrals (Mg, Si) is recogni…