Search Publications
Heavy water around the L1448-mm protostar
Codella, C.; Ceccarelli, C.; Bachiller, R. +5 more
Context. L1448-mm is the prototype of a low-mass Class 0 protostar driving a high-velocity jet. Given its bright H2O spectra observed with ISO, L1448-mm is an ideal laboratory to observe heavy water (HDO) emission.
Aims: Our aim is to image the HDO emission in the protostar surroundings, the possible occurrence of HDO emission also…
Fast, Gusty Winds Blowing from the Core of the Pre-planetary Nebula M 2-56
Sánchez Contreras, C.; Bujarrabal, V.; Miranda, L. F. +2 more
We report optical long-slit spectra and direct imaging (ground-based and with the Hubble Space Telescope (HST)) of the pre-planetary nebula M 2-56 obtained at different epochs. The optical nebula is composed of shock-excited material distributed in two pairs of nested lobes with different sizes and surface brightness. The compact, bright inner lob…
Soft band X/K luminosity ratios for gas-poor early-type galaxies
Bogdán, Á.; Gilfanov, M.
Aims: We aim to place upper limits on the combined X-ray emission from the population of steady nuclear-burning white dwarfs in galaxies. In the framework of the single-degenerate scenario, these systems, known as supersoft sources, are believed to be likely progenitors of Type Ia supernovae.
Methods: From the Chandra archive, we selecte…
Multiwavelength Observations of the Hot DB Star PG 0112+104
Kruk, J. W.; Chayer, P.; Fontaine, G. +8 more
We present a comprehensive multiwavelength analysis of the hot DB white dwarf PG 0112+104. Our analysis relies on newly acquired FUSE observations, on medium-resolution FOS and GHRS data, on archival high-resolution GHRS observations, on optical spectrophotometry both in the blue and around Hα, as well as on time-resolved photometry. From the opti…
Monopolar and bipolar auroral electric fields and their effects
de Keyser, J.; Maggiolo, R.; Echim, M.
Most of the high-altitude auroral electric fields observed by CLUSTER can be classified into monopolar and bipolar structures. The observations associate monopolar electric fields with polar cap boundary arcs, while bipolar fields tend to be linked to discrete arcs within the auroral oval and to polar cap arcs. The present paper proposes an explan…
Titan’s atomic hydrogen corona
Wurz, P.; Lammer, H.; Rauer, H. +5 more
Based on measurements performed by the Hydrogen Deuterium Absorption Cell (HDAC) aboard the Cassini orbiter, Titan's atomic hydrogen exosphere is investigated. Data obtained during the T9 encounter are used to infer the distribution of atomic hydrogen throughout Titan's exosphere, as well as the exospheric temperature. The measurements performed d…
Photospheric Radius Expansion During Magnetar Bursts
Watts, Anna L.; Kouveliotou, Chryssa; Göǧüş, Ersin +6 more
On 2008 August 24 the new magnetar SGR 0501+4516 (discovered by Swift) emitted a bright burst with a pronounced double-peaked structure in hard X-rays, reminiscent of the double-peaked temporal structure seen in some bright thermonuclear bursts on accreting neutron stars. In the latter case this is due to Photospheric Radius Expansion (PRE): when …
On the scaling properties of anisotropy of interplanetary magnetic turbulent fluctuations
Carbone, V.; Sorriso-Valvo, L.; Yordanova, E.
The anisotropic character of interplanetary magnetic-field turbulence has been studied through the analysis of Cluster data. The full tensor of the mixed second-order structure functions has been used to quatitatively measure the degree of anisotropy and its effect on small-scale turbulence. Three different regions of the near-Earth space have bee…
Fold Lens Flux Anomalies: A Geometric Approach
Goldberg, David M.; Richards, Gordon T.; Chessey, Mary K. +1 more
We develop a new approach for studying flux anomalies in quadruply imaged fold lens systems. We show that in the absence of substructure, microlensing, or differential absorption, the expected flux ratios of a fold pair can be tightly constrained using only geometric arguments. We apply this technique to 11 known quadruple lens systems in the radi…
Role of latitude of source region in Solar Energetic Particle events
Dalla, S.; Agueda, N.
Solar Energetic Particle (SEP) measurements from the Ulysses spacecraft have shown that the latitudinal separation between the parent solar flare and the nominal footpoint of the detecting spacecraft is an important parameter in ordering characteristics of the observed time-intensity profiles during SEP events. In this study, we consider data from…