Search Publications
A search for massive ultra-compact dwarf galaxies in the Centaurus galaxy cluster
Infante, L.; Hilker, M.; Kissler-Patig, M. +3 more
Context: In a previous paper, we initiated a search for ultra-compact dwarf galaxies (UCDs) in the Centaurus galaxy cluster, resulting in the discovery of 27 compact objects with -12.2<M_V<-10.9 mag. Our overall survey completeness was 15-20% within 120 kpc projected clustercentric distance.
Aims: To constrain the luminosity distribution…
The role of small versus large scale magnetic topologies in global waves
Delannée, C.
Context: Coronal waves are large-scale structures that propagate through the lower corona over distances of hundreds of megameters. They are believed to be related to coronal mass ejections (CMEs). Attrill and collaborators suggested that the propagation of the wave front is due to consecutive reconnections in the quiet Sun of favourably orientate…
Normal galaxies in the XMM-Newton fields. X-rays as a star formation indicator
Georgantopoulos, I.; Rovilos, E.; Whiting, M. +4 more
Context: We use the first XMM serendipitous source catalogue (1XMM) to compile a sample of normal X-ray galaxies.
Aims: We seek to expand the database of X-ray selected normal galaxies at intermediate redshifts and examine the relation between X-ray emission and star formation for late-type systems.
Methods: The candidates are selected bas…
Suzaku observation of the Phoenix galaxy
Bianchi, S.; Guainazzi, M.; Comastri, A. +5 more
Context: In recent years, several Seyfert 2 galaxies have been discovered that change state when observed in X-rays a few years apart, switching from Compton-thin to reflection-dominated or viceversa.
Aims: We observed a member of this class of "Changing-look" sources, the Phoenix galaxy, with {Suzaku}, with the aim of better understanding the…
Characterization of the emitting and absorbing media around the nucleus of the active galaxy UGC 11763 using XMM-Newton data
Santos-Lleó, M.; Krongold, Y.; Rodríguez-Pascual, P. +3 more
Aims: The detailed analysis of all data taken by the XMM-Newton satellite of UGC 11763 to characterize the different components that are emitting and absorbing radiation in the vicinity of the active nucleus.
Methods: The continuum emission was studied through the EPIC spectra taking profit of the spectral range of these cameras. The high reso…
Direct measurement of the formation height difference of the 630 nm Fe I solar lines
Faurobert, M.; Uitenbroek, H.; Ricort, G. +4 more
Context: Spectral lines formed over a limited height range in either a stellar or planetary atmosphere provide us with information about the physical conditions within this height range. In this context, an important quantity is the so-called line formation depth. It is usually determined from numerical calculation of the atmospheric opacity in th…
On oscillations found in an active region with EIS on Hinode
Doyle, J. G.; O'Shea, E.
Aims: Using temporal series (40'' slot) data in the ion{Fe}{xii} 195 Å line from the extreme-ultraviolet imaging spectrometer (EIS) on board the Hinode satellite, we seek to carry out a statistical study of oscillations in an active region.
Methods: Using wavelet techniques, we measure the frequency and duration of oscillations found in the ti…
The Crab pulsar and its pulsar-wind nebula in the optical and infrared
Lundqvist, P.; Tziamtzis, A.; Djupvik, A. A.
Aims. We investigate the emission mechanism and evolution of pulsars that are associated with supernova remnants.
Methods: We used imaging techniques in both the optical and near infrared, using images with very good seeing (≤0.primeprime6) to study the immediate surroundings of the Crab pulsar. In the case of the infrared, we took …
SN 1999ga: a low-luminosity linear type II supernova?
Smartt, S. J.; Altavilla, G.; Turatto, M. +11 more
Context: Type II-linear supernovae are thought to arise from progenitors that have lost most of their H envelope by the time of the explosion, and they are poorly understood because they are only occasionally discovered. It is possible that they are intrinsically rare, but selection effects due to their rapid luminosity evolution may also play an …
Magnetic evolution of superactive regions. Complexity and potentially unstable magnetic discontinuities
Romano, P.; Zuccarello, F.; Giorgi, F. +1 more
Context: It is widely accepted that solar flares are manifestations of magnetic reconnection events taking place in the solar atmosphere. Several aspects of these events remain unclear, although many efforts have been devoted to the investigation of magnetic field configurations at flare occurrence sites.
Aims: In this work, we have studied th…