Related papers: Suzaku detection of enigmatic geocoronal solar win…
We present an analysis of a Suzaku observation taken during the geomagnetic storm of 2005 August 23-24. We found time variation of diffuse soft X-ray emission when a coronal mass ejection hit Earth and caused a geomagnetic storm. The…
X-ray emission generated through solar-wind charge exchange (SWCX) is known to contaminate X-ray observation data, the amount of which is often significant or even dominant, particularly in the soft X-ray band, when the main target is…
A model of geocoronal solar wind charge exchange (SWCX) emission was built and compared to five Suzaku detections of bright geocoronal SWCX events. An exospheric neutral hydrogen distribution model, charge exchange cross sections, solar…
We report the detection of a time variable OVII line emission in a deep 100 ks Suzaku X-ray Imaging Spectrometer spectrum of the Galactic Ridge X-ray emission. The observed line intensity is too strong (11+/-2 line unit or photon cm^-2 s^-1…
We present an analysis of a pair of Suzaku spectra of the soft X-ray background (SXRB), obtained from pointings on and off a nearby shadowing filament in the southern Galactic hemisphere. Because of the different Galactic column densities…
We report the discovery of a geocoronal solar wind charge exchange (SWCX) event corresponding to the well-known 2006 December 13th coronal mass ejection (CME) event. Strong evidence for the charge exchange origin of this transient diffuse…
We present the analysis of an observation by XMM-Newton that exhibits strongly variable, low-energy diffuse X-ray line emission. We reason that this emission is due to localised solar wind charge exchange (SWCX), originating from a passing…
The ubiquitous diffuse soft (1/4 keV) X-ray background was one of the earliest discoveries of X-ray astronomy. At least some of the emission may arise from charge exchange between solar wind ions and neutral atoms in the heliosphere, but no…
In this paper, we estimate the X-ray emission from close-in exoplanets. We show that the Solar/Stellar Wind Charge Exchange Mechanism (SWCX) which produces soft X-ray emission is very effective for hot Jupiters. In this mechanism, X-ray…
Solar Wind Charge eXchange X-ray (SWCX) emission in the heliosphere and Earth's exosphere is a hard to avoid signal in soft X-ray observations of astrophysical targets. On the other hand, the X-ray imaging possibilities offered by the SWCX…
We report an apparent detection of the C VI 4p to 1s transition line at 459 eV, during a long-term enhancement (LTE) in the Suzaku north ecliptic pole (NEP) observation of 2005 September 2. The observed intensity of the line is comparable…
We report on results of imaging and spectral studies of X-ray emission from Jupiter observed by Suzaku. In 2006 Suzaku had found diffuse X-ray emission in $1\unicode{x2013}5$ keV associated with Jovian inner radiation belts. It has been…
The solar flare on July 30, 2011 was of a modest X-ray class (M9.3), but it made a strong photospheric impact and produced a "sunquake," observed with the Helioseismic and Magnetic Imager (HMI) on NASA's Solar Dynamics Observatory (SDO). In…
Solar wind charge exchange (SWCX) is the primary contamination to soft X-ray emission lines from the Milky Way (MW) hot gas. We report a solar-cycle ($\approx 10$ yr) temporal variation of observed \ion{O}{7} and \ion{O}{8} emission line…
Long-term time variabilities of the OVII (0.57 keV) emission in the soft X-ray diffuse background were studied using six Suzaku annual observations of blank sky towards the Lockman Hole made from 2006 to 2011. After time intervals in which…
We present study of the complex event consisting of several solar wind transients detected by Advanced Composition Explorer (ACE) on 4 -- 7 August 2011, that caused a geomagnetic storm with Dst$=-$110 nT. The supposed coronal sources --…
Several mechanisms have been proposed to explain the transient seis- mic emission, i.e., sunquakes, from some solar flares. Some theories associate high-energy electrons and/or white-light emission with sunquakes. High-energy charged…
We report on the timing and spectral analysis of two Suzaku observations with different flux levels of the high-mass X-ray binary KS 1947+300 during its 2013 outburst. In agreement with simultaneous NuSTAR observations, the continuum is…
We examined soft X-ray emission by the solar wind charge-exchange process around the Earth's magnetosphere using a global magnetohydrodynamic simulation model. The dayside magnetopause reconnection heats and accelerates the plasma whereby…
We present measurements of the soft X-ray background emission for 130 Suzaku observations at $75^\circ<l < 285^\circ$ and $|b|>15^\circ$ obtained from 2005 to 2015, covering nearly one solar cycle. In addition to the standard soft X-ray…