Search Publications
Optical colours of AGN in the extended Chandra deep field South: obscured black holes in early type galaxies
Georgantopoulos, I.; Rovilos, E.
We investigate the optical colours of X-ray sources from the Extended Chandra Deep Field South (ECDFS) using photometry from the COMBO-17 survey, aiming to explore AGN - galaxy feedback models. The X-ray sources populate both the “blue” and the “red sequence” on the colour-magnitude diagram. However, sources in the “red sequence” appear systematic…
Are supergranule sizes anti-correlated with magnetic activity?
Meunier, N.; Roudier, T.; Tkaczuk, R.
Context: The variation of supergranule cell sizes with the magnetic environment is still controversial.
Aims: We study this relation in detail to understand the discrepancies observed between previous results.
Methods: We determine the cell size using divergence of horizontal flows derived from local correlation tracking of intensity maps …
Measuring the dark matter velocity anisotropy in galaxy clusters
Piffaretti, R.; Hansen, S. H.
Aims:The Universe contains approximately 6 times more dark matter than normal baryonic matter, and directly observed fundamental difference between dark matter and baryons would both be significant for our understanding of dark matter structures and provide us with information about the basic characteristics of the dark matter particle. We discuss…
Imaging of star clusters in unperturbed spiral galaxies with the Advanced Camera for Surveys. I. The low luminosity galaxy NGC 45
Larsen, S. S.; Kissler-Patig, M.; Mora, M. D.
Context: Star clusters are present in almost all types of galaxies. Here we investigate the star cluster population in the low-luminosity, unperturbed spiral galaxy
Aims: Previous ground-based observ…
The CoRoT primary target HD 52265: models and seismic tests
Vauclair, G.; Vauclair, S.; Laymand, M. +1 more
Aims:HD 52265 is the only known exoplanet-host star selected as a main target for the seismology programme of the CoRoT satellite. As such, it will be observed continuously during five months, which is of particular interest when studying planetary systems. This star was misclassified as a giant in the Bright Star Catalog, while it is more probabl…
Deconvolution of HST images of the Cloverleaf gravitational lens. Detection of the lensing galaxy and a partial Einstein ring
Magain, P.; Chantry, V.
Archival HST/NICMOS-2 images of the Cloverleaf gravitational lens (H1413+117), a quadruply-imaged quasar, were analysed with a new method derived from the MCS deconvolution algorithm (Magain et al. 1998). This method is based on an iterative process which simultaneously allows us to determine the Point Spread Function (PSF) and to perform a deconv…
Determination of the light curve of the Rosetta target asteroid (2867) Steins by the OSIRIS cameras onboard Rosetta
Lamy, P.; Keller, H. U.; Mottola, S. +9 more
Context: In 2004 asteroid (2867) Steins has been selected as a flyby target for the Rosetta mission. Determination of its spin period and the orientation of its rotation axis are essential for optimization of the flyby planning.
Aims: Measurement of the rotation period and light curve of asteroid (2867) Steins at a phase angle larger than achi…
Mrk 609 : resolving the circumnuclear structure with near-infrared integral field spectroscopy
Hasinger, G.; Pott, J. -U.; Eckart, A. +5 more
Aims:We present first results of near-infrared (NIR) J and H + K ESO-SINFONI integral field spectroscopy of the composite starburst/Seyfert 1.8 galaxy Mrk 609. The data were taken during the science verification period of SINFONI. We aim to investigate the morphology and excitation conditions within the central 2 kpc. Additional Nobeyama 45 m CO(1…
The host galaxy/AGN connection. Brightness profiles of early-type galaxies hosting Seyfert nuclei
Capetti, A.; Balmaverde, B.
We recently presented evidence of a connection between the brightness profiles of nearby early-type galaxies and the properties of the AGN they host. The radio loudness of the AGN appears to be univocally related to the host's brightness profile: radio-loud nuclei are only hosted by “core” galaxies while radio-quiet AGN are only found in “power-la…
Are solar maximum fan streamers a consequence of twisting sheet structures?
Habbal, S. R.; Morgan, H.
Context: Fan streamers are often observed at low to mid latitudes in the corona at solar maximum, appearing narrow in latitudinal extent near the Sun, and fanning out with height, adopting an approximately linear, but not necessarily radial, configuration above ~3 R⊙.
Aims: We offer arguments to support the conjecture that such stru…