Search Publications

Coronal magnetic topology and the production of solar impulsive energetic electrons

Li, C.; Wang, X. Y.; Sun, L. P. +1 more

We investigate two candidate solar sources or active regions (ARs) in association with a solar impulsive energetic electron (SIEE) event on 2002 October 20. The solar particle release (SPR) times of SIEEs are derived by using their velocity dispersion with consideration of the instrumental effect. It is found that there are double electron injecti…

Polarization of Saturn's moon Iapetus. II. Comparison of the dark and the bright sides

Muinonen, K.; Tozzi, G. P.; Boehnhardt, H. +3 more

Context. The surface properties of atmosphereless solar system objects can be constrained by investigating the nature of the polarized light scattered from their surfaces.
Aims: We provide new and precise measurements of the phase angle and the wavelength dependence of linear polarization on the leading side of Iapetus over the maximum phase …

INTEGRAL/SPI data segmentation to retrieve source intensity variations

Bouchet, L.; Chauvin, M.; Amestoy, P. R. +2 more

Context. The INTEGRAL/SPI, X/γ-ray spectrometer (20 keV-8 MeV) is an instrument for which recovering source intensity variations is not straightforward and can constitute a difficulty for data analysis. In most cases, determining the source intensity changes between exposures is largely based on a priori information.
Aims: We propose techniqu…

Direct model fitting to combine dithered ACS images

Wucknitz, O.; Mahmoudian, H.

The information lost in images of undersampled CCD cameras can be recovered with the technique of "dithering". A number of subexposures is taken with sub-pixel shifts in order to record structures on scales smaller than a pixel. The standard method to combine such exposures, "Drizzle", averages after reversing the displacements, including rotation…

Detectability of micro-variables in the ASAS database

David, M.; Nitschelm, C.; Hensberge, H.

Aims: We exploit nine years of photometry in the ASAS V-band catalogue to develop a method to select in an objective way the best quality data and detect low-amplitude variables. We concentrate on bright stars (V < 10) and avoid open cluster stellar densities.
Methods: We use the (probable) members of the Sco-Cen associations as a tes…

Herschel CHESS discovery of the fossil cloud that gave birth to the Trapezium and Orion KL (Corrigendum)

Ceccarelli, C.; Dominik, C.; Caux, E. +4 more

Submillimetre photometry of 323 nearby galaxies from the Herschel Reference Survey (Corrigendum)

Clements, D. L.; Ciesla, L.; Buat, V. +23 more

Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Distribution of magnetic fields in the quiet Sun

Faurobert, M.; Ricort, G.

Context. The distribution of magnetic fields in the atmosphere of the quiet Sun has been extensively studied with various methods, but it is still a matter of debate. Previous analyses mostly rely on the inversion of spectro-polarimetric data and different methods lead to somewhat different results.
Aims: Here we do not intend to determine th…

UltraVISTA: a new ultra-deep near-infrared survey in COSMOS

Sutherland, W.; Milvang-Jensen, B.; Fynbo, J. P. U. +18 more

In this paper we describe the first data release of the UltraVISTA near-infrared imaging survey of the COSMOS field. We summarise the key goals and design of the survey and provide a detailed description of our data reduction techniques. We provide stacked, sky-subtracted images in YJHK_s and narrow-band filters constructed from data col…

Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models

Przybilla, N.; Nieva, M. -F.

Context. Early B-type stars are ideal indicators for present-day cosmic abundances since they preserve their pristine abundances and typically do not migrate far beyond their birth environments over their short lifetimes, in contrast to older stars like the Sun. They are also unaffected by depletion onto dust grains, unlike the cold/warm interstel…