Search Publications
XMM-Newton spectral properties of the ultraluminous IRAS galaxy Mrk 273
Lutz, D.; Balestra, I.; Boller, Th. +2 more
We present a 23 ks XMM-Newton observation of the Ultraluminous Infrared Galaxy (ULIRG) Mrk 273. The hard X-ray spectrum can be modeled by a highly absorbed (~7×1023 cm-2) power law plus an Fe Kα emission line. The iron line (detected at more than 99% c.l.) is broad (σ=0.26+0.37-0.17 keV), suggesting poss…
X-rays from the Type II quasar in the hyperluminous infrared galaxy IRAS F15307+3252*
Iwasawa, K.; Fabian, A. C.; Crawford, C. S. +1 more
We report the detection of X-ray emission from the hyperluminous infrared galaxy IRAS F15307 + 3252 at z= 0.93 and its properties obtained from XMM-Newton observations. Although the X-ray emission is very faint and the data are noisy, a prominent line-like feature in the observed 3-4 keV range is inferred from both photometric and spectroscopic te…
Transition Region Downflows in the Impulsive Phase of Solar Flares
Brooks, D. H.; Kurokawa, H.; Kamio, S. +2 more
We present observations of four flares that occurred during coordinated observations between the Coronal Diagnostic Spectrometer (CDS) on board SOHO and the Domeless Solar Telescope (DST) at Hida Observatory. We studied the evolution of relative Doppler velocities in the flare kernels by using He I (3.5×104 K), O V (2.2×105 K…
XMM-Newton observations of AM CVn binaries
Cropper, M.; Ramsay, G.; Hakala, P. +3 more
We present the results of XMM-Newton observations of four AM CVn systems - AM CVn, CR Boo, HP Lib and GP Com. Their light curves show very different characteristics. The X-ray light curves show no coherent pulsations, suggesting the accreting white dwarfs have relatively low magnetic field strengths. Their spectra were best modelled using a multi-…
Gamma-ray observations of explosive nucleosynthesis products
Vink, Jacco
In this review I discuss the various γ-ray emission lines that can be expected and, in some cases have been observed, from radioactive explosive nucleosynthesis products. The most important γ-ray lines result from the decay chains of 56Ni, 57Ni, and 44Ti. 56Ni is the prime explosive nucleosynthesis produ…
A mapping of martian water sublimation during early northern summer using OMEGA/Mars Express
Bibring, J. -P.; Gondet, B.; Langevin, Y. +8 more
The OMEGA imaging spectrometer aboard Mars Express has been used to map the water vapor abundance over the martian surface, from the analysis of the 2.6 µm band of H2O. As a preliminary result of this study, we present water vapor maps in the northern hemisphere at the time of the northern polar cap sublimation (Ls = 94-112 deg). The maps sh…
Discovery of X-ray eclipses from the transient source CXOGC J174540.0-290031 with XMM-Newton
Grosso, N.; Warwick, R. S.; Porquet, D. +4 more
We present the XMM-Newton observations obtained during four revolutions in Spring and Summer 2004, of CXOGC J174540.0-290031, a moderately bright transient X-ray source, located at only 2.9'' from Sgr A*. We report the discovery of sharp and deep X-ray eclipses, with a period of 27 961±5 s and a duration of about 1100±100 s, observed during the tw…
The heliospheric modulation of 3 10 MeV electrons: Modeling of changes in the solar wind speed in relation to perpendicular polar diffusion
Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +3 more
The discrepancy between cosmic ray model predictions representing solar minimum conditions in the heliosphere and the 3-10 MeV post-1998 electrons observations by the Kiel Electron Telescope (KET) onboard Ulysses suggests the need for consistent changes in model parameters with increasing solar activity. In order to reduce this discrepancy, an eff…
Observations of Hα Intensity Oscillations in a Flare Ribbon
Gallagher, Peter T.; Mathioudakis, Mihalis; Bloomfield, D. Shaun +6 more
High-cadence Hα blue wing observations of a C9.6 solar flare obtained at Big Bear Solar Observatory using the Rapid Dual Imager are presented. Wavelet and time-distance methods were used to study oscillatory power along the ribbon, finding periods of 40-80 s during the impulsive phase of the flare. A parametric study found statistically significan…
Transient Coronal Holes as Seen in the He I 1083 nm MLSO Observations
de Toma, G.; Holzer, T. E.; Burkepile, J. T. +1 more
Observations from Yohkoh SXT and SOHO EIT have shown that dimming regions often appear on the solar disk near the location of a coronal mass ejection (CME). We now can see brightenings in He I 1083 nm observations made at the Mauna Loa Solar Observatory (MLSO) that form at the same time and are cospatial with the EUV intensity dimmings observed fr…