Search Publications
Hot gas in Mach cones around Virgo cluster spiral galaxies
Bomans, D. J.; Ehle, M.; Weżgowiec, M. +5 more
Context. The detailed comparison between observations and simulations of ram-pressure stripped spiral galaxies in the Virgo cluster has led to a 3D view of the galaxy orbits within the hot intracluster medium. The 3D velocities and Mach numbers derived from simulations can be used to derive simple Mach cone geometries for Virgo spiral galaxies.
A close look at the Centaurus A group of galaxies. II. Intermediate-age populations in early-type dwarfs
Rejkuba, M.; Crnojević, D.; Grebel, E. K. +2 more
Aims: We investigate the resolved stellar content of early-type dwarf galaxies in the Centaurus A group, to estimate their intermediate-age population fractions.
Methods: We use near-infrared photometric data taken with the VLT/ISAAC instrument, together with previously analyzed archival HST/ACS data. The combination of the optical and i…
Nova M31N 2007-12b: supersoft X-rays reveal an intermediate polar?
Della Valle, M.; Pietsch, W.; Haberl, F. +4 more
Context. In the central part of
Herschel observations of the Herbig-Haro objects HH 52-54
Liseau, R.; Benedettini, M.; Justtanont, K. +11 more
Context. The emission from Herbig-Haro objects and supersonic molecular outflows is understood as cooling radiation behind shocks, which are initiated by a (proto-)stellar wind or jet. Within a given object, one often observes both dissociative (J-type) and non-dissociative (C-type) shocks, owing to the collective effects of internally varying sho…
Suzaku broad-band observations of the Seyfert 1 galaxies Mrk 509 and Mrk 841
Costantini, E.; Ponti, G.; Boisson, C. +5 more
Context. Markarian 509 and Markarian 841 are two bright Seyfert 1 galaxies with X-ray spectra characterised by a strong soft excess and a variable Fe Kα line, as shown by several X-ray observatories in the past.
Aims: We report an analysis and modelling of new Suzaku observations of these sources, taken between April and November, 2006, for M…
HST and VLT observations of the neutron star 1E 1207.4-5209
Caraveo, P. A.; Bignami, G. F.; de Luca, A. +4 more
The peculiar central compact object 1E 1207.4-5209 in the G296.5+10.0 supernova remnant has been proposed to be an “anti-magnetar” - a young neutron star born with a weak dipole field. Accretion, possibly of supernova fallback material, has also been invoked to explain a large surface temperature anisotropy as well as the generation of peculiar cy…
The deeply obscured AGN of NGC 4945. I. Spitzer-IRS maps of [Ne V], [Ne II], H2 0-0 S(1), S(2), and other tracers
Smith, J. D.; Spaans, M.; Spoon, H. W. W. +1 more
Context. The nearly edge-on galaxy NGC 4945 is one of the closest galaxies where an AGN and starburst coexist, and is one of the brightest sources at 100 keV. Near and mid-infrared spectroscopy have shown very strong obscuration of its central region, rivaled only in strength by some of the most deeply obscured ULIRGs.
Aims: We determine the …
The metal contents of two groups of galaxies
Kaastra, J. S.; de Plaa, J.; de Vries, C. P. +4 more
Context. The hot gas in clusters and groups of galaxies is continuously being enriched with metals from supernovae and stars. It is well established that the enrichment of the gas with elements from oxygen to iron is mainly caused by supernova explosions. The origins of nitrogen and carbon are still being debated. Possible candidates include massi…
Near-IR search for lensed supernovae behind galaxy clusters. III. Implications for cluster modeling and cosmology
Amanullah, R.; Goobar, A.; Mörtsell, E. +6 more
Context. Massive galaxy clusters at intermediate redshifts act as gravitational lenses that can magnify supernovae (SNe) occurring in background galaxies.
Aims: We assess the possibility of using lensed SNe to constraint the mass models of galaxy clusters and the Hubble parameter at high redshift.
Methods: Owing to the standard candle na…
Solar winds along curved magnetic field lines
Chen, Y.; Li, B.; Xia, L. D.
Context. Both remote-sensing measurements using the interplanetary scintillation (IPS) technique and in-situ measurements by the Ulysses spacecraft show a bimodal structure for the solar wind at solar minimum conditions. At present it still remains to address why the fast wind is fast and the slow wind is slow. While a robust empirical correlation…