Search Publications
A short introduction to broad and variable iron lines around black holes
Fabian, A. C.
Accreting black holes often show iron line emission in their X-ray spectra. When this line emission is very broad or variable then it is likely to originate from close to the black hole. The theory and observations of such broad and variable iron lines are briefly reviewed here. In order for a clear broad line to be found, one or more of the follo…
CLUSTER observation of collisionless transport at the magnetopause
Fränz, M.; Dandouras, I.; Rème, H. +5 more
On May 10, 2002 the CLUSTER spacecraft (SC) encountered a ~450 km (five magnetosheath thermal proton gyro-radii) wide high-latitude magnetopause (MP). Magnetic field observations indicate the crossing of a ~130 km thick MP current sheet (CS) located inside a magnetic hole. Proton flux measurements diagnose a dense boundary layer (BL) directly atta…
Three-dimensional Structure of the 2002 April 21 Coronal Mass Ejection
Raymond, J. C.; Ko, Y. -K.; Lee, J. -Y. +1 more
A three-dimensional reconstruction of the 2002 April 21 partial halo Coronal Mass Ejection (CME) has been made based on the O VI 1032 Å and [Fe XVIII] 974 Å lines observed by the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SOHO). We use the Doppler velocities to derive the CME structure along the li…
Analysis of a multi-wavelength time-resolved observation of a coronal loop
Ciaravella, A.; Reale, F.
Aims.We analyze a well-defined loop system detected in a time-resolved observation in several spectral bands to characterize the structure and evolution of coronal loops. Methods.The dataset includes simultaneous sequences of images in the 171 Å, 195 Å and 284 Å filter bands of TRACE, and in one filter of Yohkoh/SXT, with a time coverage of about …
Ultraviolet Observations of Prominence Activation and Cool Loop Dynamics
Landi, E.; Kucera, T. A.
In this paper we investigate the thermal and dynamic properties of dynamic structures in and around a prominence channel observed on the limb on 2003 April 17. Observations were taken with the Solar and Heliospheric Observatory's Solar Ultraviolet Measurements of Emitted Radiation (SOHO SUMER) in lines formed at temperatures from 80,000 K to 1.6 M…
4U 1344-60: a bright intermediate Seyfert galaxy at z = 0.012 with a relativistic Fe Kα emission line
Motch, C.; Bianchi, S.; Guainazzi, M. +6 more
We present analysis of the optical and X-ray spectra of the low Galactic latitude bright (F_2-10 = 3.6 × 10-11 erg cm-2 s-1) source 4U 1344-60. On the basis of the optical data we propose to classify 4U 1344-60 as an intermediate type Seyfert galaxy and we measure a value of z = 0.012±0.001 for its redshift. From t…
Star-forming QSO host galaxies
Barthel, P. D.
Context: .The recent finding of substantial masses of cold molecular gas as well as young stellar populations in the host galaxies of intermediate luminosity quasars is at odds with results of Hubble Space Telescope imaging studies since the latter appear to yield mature, quiescent early type hosts.
Aims: .The characterization as "quiescent" f…
The coronal Ne/O abundance of α Centauri
Liefke, C.; Schmitt, J. H. M. M.
Recent improvements in the modeling of solar convection and line formation led to downward revisions of the solar photospheric abundances of the lighter elements, which in turn led to changes in the radiative opacity of the solar interior and hence to conflicts with the solar convection zone depth as inferred from helioseismic oscillation frequenc…
A global 2.5-dimensional three fluid solar wind model with alpha particles
Li, Xing; Li, Bo; Labrosse, Nicolas
A global 2.5-dimensional three fluid solar wind model is presented. Two ion species, namely protons and alpha particles, are heated by an empirical energy flux while electrons are heated by the classical heat flux and Coulomb coupling with ions. It is found that for a reasonable relative speed between alpha particles and protons at 1 AU to be achi…
Measuring 26Al and 60Fe in the Galaxy
Diehl, Roland
With the SPI high-resolution spectrometer on INTEGRAL, new results have been obtained for long-lived radioactive 26Al and 60Fe in our Galaxy: 26Al sources apparently share the pattern of Galactic rotation in the inner Galaxy, and thus allow to estimate a total mass of 26Al in the Galaxy of 2.8M⊙