Search Publications
On the relationship of shock waves to flares and coronal mass ejections
Hillaris, A.; Preka-Papadema, P.; Nindos, A. +1 more
Context. Metric type II bursts are the most direct diagnostic of shock waves in the solar corona.
Aims: There are two main competing views about the origin of coronal shocks: that they originate in either blast waves ignited by the pressure pulse of a flare or piston-driven shocks due to coronal mass ejections (CMEs). We studied three well-ob…
VLT-VIMOS integral field spectroscopy of luminous and ultraluminous infrared galaxies. III. The atlas of the stellar and ionized gas distribution
Colina, L.; Monreal-Ibero, A.; Arribas, S. +3 more
Context. Luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) are much more numerous at higher redshifts than locally, dominating the star-formation rate density at redshifts ~1-2. Therefore, they are important objects in order to understand how galaxies form and evolve through cosmic time. Local samples provide a unique opportunity to …
The hard X-ray emission of Centaurus A
Terrier, R.; Jean, P.; Beckmann, V. +2 more
Context. The radio galaxy Cen A has been detected all the way up to the TeV energy range. This raises the question about the dominant emission mechanisms in the high-energy domain.
Aims: Spectral analysis allows us to put constraints on the possible emission processes. Here we study the hard X-ray emission, in order to distinguish between a t…
Witnessing the magnetospheric boundary at work in Vela X-1
Santangelo, A.; Doroshenko, V.; Suleimanov, V.
We present an analysis of the Vela X-1 "off-states" based on Suzaku observations taken in June 2008. Defined as states in which the flux suddenly decreases below the instrumental sensitivity, these "off-states" have been interpreted by several authors as the onset of the "propeller regime". For the first time ever, however, we find that the source…
Asymmetries of the Stokes V profiles observed by HINODE SOT/SP in the quiet Sun
Sánchez Almeida, J.; Viticchié, B.
Aims: A recent analysis of polarization measurements of HINODE SOT/SP in the quiet Sun pointed out very complex shapes of Stokes V profiles. Here we present the first classification of the SOT/SP circular polarization measurements with the aim of highlighting exhaustively the whole variety of Stokes V shapes emerging from the quiet Sun.
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A new comprehensive 2D model of the point spread functions of the XMM-Newton EPIC telescopes: spurious source suppression and improved positional accuracy
Read, A. M.; Saxton, R. D.; Rosen, S. R. +1 more
Aims: We describe here a new full 2D parameterization of the PSFs of the three XMM-Newton EPIC telescopes as a function of instrument, energy, off-axis angle and azimuthal angle, covering the whole field-of-view (FoV) of the three EPIC detectors. It models the general PSF envelopes, the primary and secondary spokes, their radial dependencies,…
Two formation channels of ultra-compact dwarf galaxies in Hickson compact groups
Mendes de Oliveira, C.; Hilker, M.; Ziegler, B. L. +3 more
Context. The formation of ultra-compact dwarf galaxies (UCDs) is believed to be driven by interaction, and UCDs are abundant in the cores of galaxy clusters, environments that mark the end-point of galaxy evolution. Nothing is known about the properties of UCDs in compact groups of galaxies, environments where most of galaxy evolution and interact…
Radial profiles of Fe abundance in the intracluster medium of nearby clusters observed with XMM-Newton
Matsushita, K.
Aims: The abundances of Fe in the intracluster medium of nearby (z < 0.08) clusters were measured up to 0.3 ~ 0.5r180.
Methods: We analyzed 28 clusters of galaxies observed with XMM-Newton. We derived Fe abundances from the flux ratios of Fe lines to the continuum within an energy range of 3.5-6 keV to minimize and evaluate…
Image reconstruction in optical interferometry: benchmarking the regularization
Thiébaut, E.; Malbet, F.; Renard, S.
Context. With the advent of visible and infrared long-baseline interferometers with more than two telescopes, both the size and the completeness of interferometric data sets have significantly increased, allowing images based on models with no a priori assumptions to be reconstructed with an aperture synthesis technique.
Aims: Our main object…
GRB 091127/SN 2009nz and the VLT/X-shooter spectroscopy of its host galaxy: probing the faint end of the mass-metallicity relation
Covino, S.; D'Avanzo, P.; Sánchez-Ramírez, R. +36 more
We perform a detailed study of the gamma-ray burst GRB 091127/SN 2009nz host galaxy at z = 0.490 using the VLT/X-shooter spectrograph in slit and integral-field unit (IFU) mode. From the analysis of the optical and X-ray afterglow data obtained from ground-based telescopes and Swift-XRT, we confirm the presence of a bump associated with SN 2009nz …