Search Publications
Experimental Investigations of the Comet Lander Philae Touchdown Dynamics
Ulamec, Stephan; Biele, Jens; Roll, Reinhard +5 more
The comet lander Philae (as part of Europe's Rosetta mission) is en route to its target, 67/P Churyumov-Gerasimenko. With landing operations coming up at the end of 2014, a partial retesting of the Philae lander's touchdown system was carried out in spring of 2013. Intensive testing was performed as part of Philae's design and verification program…
A multi-method approach to radial-velocity measurement for single-object spectra
Gosset, E.; Damerdji, Y.; Katz, D. +5 more
Context. The derivation of radial velocities from large numbers of spectra that typically result from survey work, requires automation. However, except for the classical cases of slowly rotating late-type spectra, existing methods of measuring Doppler shifts require fine-tuning to avoid a loss of accuracy due to the idiosyncrasies of individual sp…
Where are the Mini Kreutz-family Comets?
Kracht, Rainer; Ye, Quan-Zhi; Hui, Man-To +1 more
The Kreutz family of sungrazing comets contains over 2000 known members, many of which are believed to be under ~100 m sizes (mini comets) and have only been studied at small heliocentric distances (r H) with space-based SOHO/STEREO spacecraft. To understand the brightening process of mini Kreutz comets, we conducted a survey using CFHT…
Modeling VIRTIS/VEX O2(a1∆g) nightglow profiles affected by the propagation of gravity waves in the Venus upper mesosphere
Bellucci, G.; Altieri, F.; Piccioni, G. +3 more
In this work we describe a model of the perturbation of the O2(a1Δg) nightglow limb profiles by the action of gravity waves (GWs) propagating in the Venus' upper atmosphere. Data have been acquired by the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) on board the European Space Agency mission Venus Exp…
Sunspot Group Development in High Temporal Resolution
Ludmány, A.; Baranyi, T.; Muraközy, J.
The Solar and Heliospheric Observatory/Michelson Doppler Imager - Debrecen Data (SDD) sunspot catalogue provides an opportunity to study the details and development of sunspot groups on a large statistical sample. In particular, the SDD data allow the differential study of the leading and following parts with a temporal resolution of 1.5 hours. In…
Reciprocatory magnetic reconnection in a coronal bright point
Ding, M. D.; Chen, P. F.; Ji, H. S. +1 more
Context. Coronal bright points (CBPs) are small-scale and long-duration brightenings in the lower solar corona. They are often explained in terms of magnetic reconnection.
Aims: We aim to study the substructures of a CBP and clarify the relationship among the brightenings of different patches inside the CBP.
Methods: The event was observ…
Discontinuities in the magnetic field near Enceladus
Dougherty, Michele K.; Saur, Joachim; Kriegel, Hendrik +2 more
The plasma interaction of Saturn's icy moon Enceladus generates a hemisphere coupling current system that directly connects the giant planet's northern and southern polar magnetosphere. Based on Cassini magnetometer observations from all 20 targeted Enceladus flybys between 2004 and 2014, we study the magnetic field discontinuities associated with…
A radio characterization of Galactic compact bubbles
Paladini, R.; Umana, G.; Agliozzo, C. +6 more
We report the radio observations of a subsample of the 428 Galactic compact bubbles discovered at 24 µm with the MIPSGAL survey. Pervasive through the entire Galactic plane, these objects are thought to be different kinds of evolved stars. The very large majority of the bubbles (∼70 per cent) are however not yet classified. We conducted radi…
Hα photometry of low-mass stars in 47 Tucanae: chromospheric activity and exotica
Panagia, N.; Pasquini, L.; Beccari, G. +1 more
We have used archival Hubble Space Telescope observations obtained with the Advanced Camera for Surveys to study the Hα emission properties of main-sequence stars in the globular cluster 47 Tucanae. Using a combination of multiband observations in the F606W, F814W and F658N bands, we search for stars showing Hα excess emission. An accurate photome…
A Multi-level Solver for Gaussian Constrained Cosmic Microwave Background Realizations
Eriksen, H. K.; Seljebotn, D. S.; Mardal, K. -A. +2 more
We present a multi-level solver for drawing constrained Gaussian realizations or finding the maximum likelihood estimate of the cosmic microwave background sky, given noisy sky maps with partial sky coverage. The method converges substantially faster than existing Conjugate Gradient (CG) methods for the same problem. For instance, for the 143 GHz …