Search Publications
Herschel PACS and SPIRE Observations of Blazar PKS 1510-089: A Case for Two Blazar Zones
Szczerba, Ryszard; Nalewajko, Krzysztof; Madejski, Greg M. +5 more
We present the results of observations of blazar PKS 1510-089 with the Herschel Space Observatory PACS and SPIRE instruments, together with multiwavelength data from Fermi/LAT, Swift, SMARTS, and Submillimeter Array. The source was found in a quiet state, and its far-infrared spectrum is consistent with a power law with a spectral index of α ~= 0.…
The 12C/13C Ratio on Titan from Cassini INMS Measurements and Implications for the Evolution of Methane
Nixon, Conor A.; Mousis, Olivier; Lunine, Jonathan I. +6 more
We have re-evaluated the Cassini Ion Neutral Mass Spectrometer (INMS) 12C/13C ratios in the upper atmosphere of Titan based on new calibration sensitivities and an improved model for the NH3 background in the 13CH4 mass channel. The INMS measurements extrapolated to the surface give a 12<…
X-Ray Emission from an Asymmetric Blast Wave and a Massive White Dwarf in the Gamma-Ray Emitting Nova V407 Cyg
Chomiuk, Laura; Mukai, Koji; Donato, Davide +2 more
Classical nova events in symbiotic stars, although rare, offer a unique opportunity to probe the interaction between ejecta and a dense environment in stellar explosions. In this work, we use X-ray data obtained with Swift and Suzaku during the recent classical nova outburst in V407 Cyg to explore such an interaction. We find evidence of both equi…
Optical extinction due to aerosols in the upper haze of Venus: Four years of SOIR/VEX observations from 2006 to 2010
Bertaux, Jean-Loup; Vandaele, Ann Carine; Robert, Séverine +3 more
The variability of the aerosol loading in the mesosphere of Venus is investigated from a large data set obtained with SOIR, a channel of the SPICAV instrument suite onboard Venus Express. Vertical profiles of the extinction due to light absorption by aerosols are retrieved from a spectral window around 3.0 µm recorded in many solar occultati…
Solar Wind Models from the Chromosphere to 1 AU
Velli, Marco; Hansteen, Viggo H.
Recent models of the fast solar wind are characterized by low coronal electron temperatures while proton, α-particle, and minor ion temperatures are expected to be quite high and generally anisotropic, including large temperatures perpendicular to the magnetic field and parallel beams. This entails that the electric field should be relatively unim…
Observations of Titan’s Northern lakes at 5 µm: Implications for the organic cycle and geology
Le Mouélic, S.; Rodriguez, S.; Sotin, C. +13 more
Since Titan entered Northern spring in August 2009, the North Pole has been illuminated allowing observations at optical wavelengths. On June 5, 2010 the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft observed the Northern Pole area with a pixel size from 3 to 7 km. Since, as we demonstrate, little of the solar flux…
Radio Imaging of Shock-accelerated Electrons Associated with an Erupting Plasmoid on 2010 November 3
Krucker, Säm; Lin, R. P.; Bain, H. M. +1 more
We present observations of a metric type II solar radio burst that occurred on the 3rd of November 2010 in association with an erupting plasmoid. The eruption was well observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory and the Reuven Ramaty High Energy Solar Spectroscopic Imager, while the burst occurred in …
X-ray spectral states and metallicity in the ultraluminous X-ray sources NGC 1313 X-1 and X-2
Pintore, Fabio; Zampieri, Luca
We present a systematic analysis of the X-ray spectra of NGC 1313 X-1 and NGC 1313 X-2, using three years of XMM-Newton observations. We fitted the continuum with a Comptonization model plus a multicolour blackbody disc, which describes the effects of an accretion disc plus a corona. We checked the consistency of this spectral model on the basis o…
Earth-based detection of Uranus' aurorae
André, N.; Dougherty, M. K.; Cecconi, B. +16 more
This study is based on multi-planet multi-wavelength observations of planetary aurorae throughout the heliosphere, acquired along the propagation path of a series of consecutive interplanetary shocks. The underlying motivation to track the shocks was to increase the probability of detection of auroral emissions at Uranus. Despite several Earth-bas…
On the Doppler Velocity of Emission Line Profiles Formed in the "Coronal Contraflow" that Is the Chromosphere-Corona Mass Cycle
De Pontieu, Bart; McIntosh, Scott W.; Tian, Hui +1 more
This analysis begins to explore the complex chromosphere-corona mass cycle using a blend of imaging and spectroscopic diagnostics. Single Gaussian fits (SGFs) to hot emission line profiles (formed above 1 MK) at the base of coronal loop structures indicate material blueshifts of 5-10 km s-1, while cool emission line profiles (formed bel…