Search Publications
The high-energy environment in the super-Earth system CoRoT-7
Schmitt, J. H. M. M.; Czesla, S.; Lalitha, S. +3 more
High-energy irradiation of exoplanets has been identified to be a key influence on the stability of these planets' atmospheres. So far, irradiation-driven mass-loss has been observed only in two Hot Jupiters, and the observational data remain even more sparse in the super-Earth regime. We present an investigation of the high-energy emission in the…
X-ray follow-up observations of the two γ-ray pulsars PSR J1459-6053 and PSR J1614-2230
Hill, A. B.; Guillemot, L.; Rea, N. +6 more
Aims: We have observed two newly detected γ-ray pulsars, PSR J1459-6053 and PSR J1614-2230, in the X-ray domain with XMM-Newton to try to enlarge the sample of pulsars for which multi-wavelength data exist. We use these data with the aim of understanding the pulsar emission mechanisms of these pulsars.
Methods: We analysed the X-ray spec…
Extranuclear Hα-emitting complexes in low-z (U)LIRGs: precursors of tidal dwarf galaxies?
Colina, L.; Arribas, S.; Miralles-Caballero, D.
This paper characterizes the physical and kinematic properties of external massive star-forming regions in a sample of (U)LIRGs. We use high angular resolution ACS images from the Hubble Space Telescope (HST) in F435W (~B) and F814W (~I) bands, as well as Hα -line emission maps obtained with integral field spectroscopy. We find 31 external Hα -emi…
Unusual Stokes V profiles during flaring activity of a delta sunspot
Fletcher, L.; Snik, F.; Fischer, C. E. +2 more
Aims: We analyze a set of full Stokes profile observations of the flaring active region NOAA 10808. The region was recorded with the Vector-Spectromagnetograph of the Synoptic Optical Long-term Investigations of the Sun facility. The active region produced several successive X-class flares between 19:00 UT and 24:00 UT on September 13, 2005 a…
The relation between surface star formation rate density and spiral arms in NGC 5236 (M 83)
Larsen, S. S.; Silva-Villa, E.
Context. For a long time the consensus has been that star formation rates are higher in the interior of spiral arms in galaxies, compared to inter-arm regions. However, recent studies have found that the star formation inside the arms is not more efficient than elsewhere in the galaxy. Previous studies have based their conclusion mainly on integra…
Discovery of a magnetic field in the early B-type star σ Lupi
Wade, G. A.; Kolenberg, K.; Grunhut, J. H. +6 more
Context. Magnetic early B-type stars are rare. Indirect indicators are needed to identify them before investing in time-intensive spectropolarimetric observations.
Aims: We use the strongest indirect indicator of a magnetic field in B stars, which is periodic variability of ultraviolet (UV) stellar wind lines occurring symmetric about the app…
Cross helicity at the solar surface by simulations and observations
Küker, M.; Schnerr, R. S.; Rüdiger, G.
A result of the quasilinear mean-field theory for driven magnetohydrodynamic (MHD) turbulence is that the observed cross helicity ⟨u·b⟩ may directly yield the magnetic eddy diffusivity ηT of the quiet Sun. In order to model the cross helicity at the solar surface, magnetoconvection under the presence of a vertical large-scale magnetic f…
The solar hydrogen Lyman α to Lyman β line ratio
Vial, J. -C.; Curdt, W.; Schühle, U. +2 more
Aims: We investigate the variation in the solar hydrogen Lyman α (Lyα) to Lyman β (Lyβ) line ratio as a function of the solar activity by taking into account new results obtained by SoHO/SUMER and TIMED/SEE.
Methods: We reanalyze data of quiet and active regions previously collected with the LPSP multichannel instrument on OSO8. We then …
The peculiar isolated neutron star in the Carina Nebula. Deep XMM-Newton and ESO-VLT observations of 2XMM J104608.7-594306
Motch, C.; Treves, A.; Pilia, M. +5 more
While fewer in number than the dominant rotation-powered radio pulsar population, peculiar classes of isolated neutron stars (INSs) - which include magnetars, the ROSAT-discovered "Magnificent Seven" (M7), rotating radio transients (RRATs), and central compact objects in supernova remnants (CCOs) - represent a key element in understanding the neut…
A hydrodynamic study of the circumstellar envelope of α Scorpii
Reimers, D.; Hagen, H. -J.; Baade, R. +1 more
Context. Both the absolute mass-loss rates and the mechanisms that drive the mass loss of late-type supergiants are still not well known. Binaries such as α Sco provide the most detailed empirical information about the winds of these stars.
Aims: Our goal was to improve the binary technique for the determination of the mass-loss rate of