Search Publications
Oscillations in a network region observed in the Hα line and their relation to the magnetic field
Georgoulis, M. K.; Tziotziou, K.; Tsiropoula, G. +1 more
Aims: Our aim is to gain a better understanding of the interaction between acoustic oscillations and the small-scale magnetic fields of the Sun. To this end, we examine the oscillatory properties of a network region and their relation to the magnetic configuration of the chromosphere. We link the oscillatory properties of a network region and…
The star cluster-field star connection in nearby spiral galaxies. I. Data analysis techniques and application to NGC 4395
Larsen, S. S.; Silva-Villa, E.
Context. It is generally assumed that a large fraction of stars are initially born in clusters. However, a large fraction of these disrupt on short timescales and the stars end up belonging to the field. Understanding this process is of paramount importance if we wish to constrain the star formation histories of external galaxies using star cluste…
Spectral energy distribution of hyperluminous infrared galaxies
Miniutti, G.; Carrera, F. J.; Panessa, F. +1 more
Aims: The relationship between star formation and super-massive black hole growth is central to our understanding of galaxy formation and evolution. Hyperluminous infrared galaxies (HLIRG) are unique laboratories to investigate the connection between starburst (SB) and active galactic nuclei (AGN), because they exhibit extreme star-formation …
The evolutionary status of the UX Orionis star RZ Piscium
Grinin, V. P.; Potravnov, I. S.; Musaev, F. A.
The star RZ Psc is one of the most enigmatic members of the UX Ori star family. It shows all properties that are typical for these stars (the light variability, high linear polarization in deep minima, the blueing effect) except for one: it lacks any signatures of youth. With the lithium line 6708 Å as a rough estimate for the stellar age, we show…
Water abundances in high-mass protostellar envelopes: Herschel observations with HIFI
de Graauw, Th.; Liseau, R.; Braine, J. +68 more
Aims: We derive the dense core structure and the water abundance in four massive star-forming regions in the hope of understanding the earliest stages of massive star formation.
Methods: We present Herschel/HIFI observations of the para-H2O 111-000 and 202-111 and the para-H_218…
Θ1 Orionis C - A triple system?
Bychkov, V.; Lehmann, H.; Vitrichenko, E. +2 more
Context. As the brightest star in the Trapezium cluster, Θ1 Ori C is the youngest and nearest to us among O-stars. It is considered to be a multiple system where the main component is an oblique magnetic rotator.
Aims: Here, we aim at explaining the structure of the Θ1 Ori C system. We check for a new hypothesis about th…
Stochastic orbital migration of small bodies in Saturn's rings
Papaloizou, J. C. B.; Rein, H.
Many small moonlets that create propeller structures have been found in Saturn's rings by the Cassini spacecraft. We study the dynamical evolution of such 20-50 m sized bodies, which are embedded in Saturn's rings. We estimate the importance of various interaction processes with the ring particles on the moonlet's eccentricity and semi-major axis …
The DAFT/FADA survey. I. Photometric redshifts along lines of sight to clusters in the z = [0.4, 0.9] interval
Ilbert, O.; Schrabback, T.; Allam, S. +20 more
Context. As a contribution to the understanding of the dark energy concept, the Dark energy American French Team (DAFT, in French FADA) has started a large project to characterize statistically high redshift galaxy clusters, infer cosmological constraints from weak lensing tomography, and understand biases relevant for constraining dark energy and…
A long hard look at the minimum state of PG 2112+059 with XMM-Newton
Schartel, N.; Rodríguez-Pascual, P. M.; Santos-Lleó, M. +3 more
Aims: Our observational aim is to perform a long X-ray observation of the quasar PG 2112+059 in its low or minimum state. Starting form this very peculiar emission state, we intend to constrain the intrinsic emission mechanism by comparing new and old data, corresponding to different source states.
Methods: XMM-Newton successfully detect…
Multiband photometric decomposition of nuclear stellar disks
Morelli, L.; Dalla Bontà, E.; Corsini, E. M. +4 more
Context. Small, bright stellar disks with scale lengths of a few tens of parsec are known to reside in the center of galaxies. They are believed to have formed in a dissipational process as the end result of star formation in gas either accreted during a merging (or acquisition) event or piled up by the secular evolution of a nuclear bar. Only a f…