Search Publications
Asteroid 2867 Steins. II. Multi-telescope visible observations, shape reconstruction, and rotational state
Jorda, L.; Lamy, P. L.; Colas, F. +14 more
Context: Asteroid 2867 Steins is the first target of the Rosetta space mission with a flyby scheduled in September 2008.
Aims: An early physical characterization is needed to optimize the flyby parameters and the science operations, and to maximize the scientific return. The aim of this article is to characterize the shape and rotational state…
Non-thermal bremsstrahlung from supernova remnants and the effect of Coulomb losses
Vink, Jacco
Aims: We investigate the shape of the electron cosmic ray spectrum in the range up to ~1000 keV, assuming that the acceleration process at the shock results in a power law in momentum, and that downstream of the shock the spectrum is affected by Coulomb interactions with background electrons only.
Methods: In the non-relativistic regime one ca…
On the morphology of sigma-drop galaxies
Knapen, J. H.; Comerón, S.; Beckman, J. E.
Context: Local reductions of the stellar velocity dispersion in the central regions of galaxies are known as sigma-drops (σ-drops). Knowing the origin of these features can lead to better understanding of inner galactic dynamics.
Aims: We present a sample of 20 σ-drop galaxies matched with a control sample of galaxies without σ-drop in order t…
Environmental effects on the globular cluster blue straggler population: a statistical approach
Moretti, A.; Piotto, G.; de Angeli, F.
Context: Blue stragglers stars (BSS) constitute an ubiquitous population of objects whose origin involves both dynamical and stellar evolution.
Aims: In this paper we study the properties of a catalogue of BSS extracted from an homogeneous sample of 56 Galactic globular clusters (GC) observed with Wide-Field Planetary Camera 2 on board of Hubb…
High resolution radio study of the pulsar wind nebula within the supernova remnant G0.9+0.1
Decourchelle, A.; Giacani, E.; Dubner, G.
Aims: We have conducted a study in radio wavelengths and in X-rays of the pulsar wind nebula (PWN) in the supernova remnant (SNR) G0.9+0.1 with the goal of investigating in detail its morphology and to accurately determine its characteristic parameters.
Methods: To carry out this research we have observed the PWN at λ3.6 and 6 cm using the Aus…
High resolution spectroscopy of the inner ring of SN 1987A
Sollerman, J.; Lundqvist, P.; Spyromilio, J. +8 more
We discuss high resolution VLT/UVES observations (FWHM ~ 6 km s-1) from October 2002 (day ~5700 past explosion) of the shock interaction of SN 1987A and its circumstellar ring. A large number of narrow emission lines from the unshocked ring, with ion stages from neutral up to Ne V and Fe VII, have been identified. A nebular analysis of …
Near-infra-red spectroscopic ages of massive star clusters in M 82
Smith, L. J.; Gallagher, J. S., III; Mouhcine, M. +3 more
Context: Like other starburst galaxies, M 82 hosts compact, massive (>5 × 105 M⊙) young star clusters that are interesting both in their own right and as benchmarks for population synthesis models.
Aims: In addition to assessing or reassessing the properties of some of the brightest near-IR sources in M 82, this paper …
Signature of mass supply to quiet coronal loops
Tu, C. -Y.; Marsch, E.; Tian, H. +2 more
Aims:The physical implication of large blue shift of Ne viii in the quiet Sun region is investigated in this paper.
Methods: We compare the significant Ne viii blue shifts, which are visible as large blue patches on the Doppler-shift map of a middle-latitude quiet-Sun region observed by SUMER, with the coronal magnetic-field structures as reco…
A nanoflare model for active region radiance: application of artificial neural networks
Solanki, S. K.; Innes, D. E.; Safari, H. +2 more
Context: Nanoflares are small impulsive bursts of energy that blend with and possibly make up much of the solar background emission. Determining their frequency and energy input is central to understanding the heating of the solar corona. One method is to extrapolate the energy frequency distribution of larger individually observed flares to lower…
Neon and oxygen in low activity stars: towards a coronal unification with the Sun
Schmitt, J. H. M. M.; Robrade, J.; Favata, F.
Aims: The disagreement between helioseismology and a recent downward revision of solar abundances has resulted in a controversy about the true neon abundance of the Sun and other stars. We study the coronal Ne/O abundance ratios of nearby stars with modest activity levels and investigate a possible peculiarity of the Sun among the stellar populati…