Search Publications
Physical properties of the ESA Rosetta target asteroid (21) Lutetia. I. The triaxial ellipsoid dimensions, rotational pole, and bulk density
Carry, B.; Weaver, H. A.; Merline, W. J. +6 more
Context. Asteroid (21) Lutetia was the target of the ESA Rosetta mission flyby in 2010 July.
Aims: We seek the best size estimates of the asteroid, the direction of its spin axis, and its bulk density, assuming its shape is well described by a smooth featureless triaxial ellipsoid. We also aim to evaluate the deviations from this assumption. …
Resolving the dusty circumstellar environment of the A[e] supergiant HD 62623 with the VLTI/MIDI
Lopez, B.; Meilland, A.; Millour, F. +4 more
Context. B[e] stars are hot stars surrounded by circumstellar gas and dust which is responsible for the presence of emission lines and IR-excess in their spectra. How dust can be formed in this highly illuminated and diluted environment remains an open issue.
Aims: HD 62623 is one of the very few A-type supergiants showing the B[e] phenomenon…
Central galaxy growth and feedback in the most massive nearby cool core cluster
Böhringer, H.; Simionescu, A.; Fabian, A. C. +4 more
We present multiwavelength observations of the centre of RXCJ1504.1 - 0248 - the galaxy cluster with the most luminous and relatively nearby cool core at z ~ 0.2. Although there are several galaxies within 100kpc of the cluster core, only the brightest cluster galaxy (BCG), which lies at the peak of the X-ray emission, has blue colours and strong …
Ground-based observations of diffuse auroral frequencies in the context of whistler mode chorus
Samara, M.; Michell, R. G.
We present a case study of an active auroral event containing diffuse auroral structures. These data were collected on 04 February 2009 during a ground-based observational campaign at Poker Flat, Alaska (L ∼ 6), from January through April 2009. They were used to extract the frequencies of pulsating auroral structures that lasted many hours after s…
Mapping Titan's HCN in the far infra-red: implications for photochemistry
Irwin, P. G. J.; Teanby, N. A.; de Kok, R. +1 more
Proper Motion of the Sagittarius Dwarf Galaxy Based on Hubble Space Telescope Imaging
Piatek, Slawomir; Pryor, Carlton; Olszewski, Edward W.
We have derived a proper motion of Sagittarius using archival data obtained with the Hubble Space Telescope. The data consist of imaging at three epochs with a time baseline of about four years in three distinct fields. The zero point for the proper motion is based on the foreground Galactic stellar populations along the line of sight. The measure…
Properties of compact 250 µm emission and H II regions in M 33 (HERM33ES)
Boquien, M.; Braine, J.; Calzetti, D. +12 more
Aims: Within the framework of the HERM33ES key program, using the high resolution and sensitivity of the Herschel photometric data, we study the compact emission in the Local Group spiral galaxy M 33 to investigate the nature of the compact SPIRE emission sources. We extracted a catalogue of sources at 250 µm in order to investigate the…
An HST/WFPC2 survey of bright young clusters in M 31. IV. Age and mass estimates
Barmby, P.; Bellazzini, M.; Galleti, S. +11 more
Aims: We present the main results of an imaging survey of possible young massive clusters (YMC) in M 31 performed with the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space Telescope (HST), with the aim of estimating their age and their mass. We obtained shallow (to B ∼ 25) photometry of individual stars in 19 clusters (of the 20 …
Dynamical and magnetic field time constants for Titan's ionosphere: Empirical estimates and comparisons with Venus
Luhmann, J. G.; Wahlund, J. -E.; Ågren, K. +12 more
Plasma in Titan's ionosphere flows in response to forcing from thermal pressure gradients, magnetic forces, gravity, and ion-neutral collisions. This paper takes an empirical approach to the ionospheric dynamics by using data from Cassini instruments to estimate pressures, flow speeds, and time constants on the dayside and nightside. The plasma fl…
Trend of photospheric magnetic helicity flux in active regions generating halo coronal mass ejections
Guglielmino, S. L.; Romano, P.; Spadaro, D. +5 more
Context. Coronal mass ejections (CMEs) are very energetic events (~ 1032 erg) initiated in the solar atmosphere, resulting in the expulsion of magnetized plasma clouds that propagate into interplanetary space. It has been proposed that CMEs can play an important role in shedding magnetic helicity, avoiding its endless accumulation in th…