Search Publications
Solar off-limb line widths: Alfvén waves, ion-cyclotron waves, and preferential heating
Dolla, L.; Solomon, J.
Context: Alfvén waves and ion-cyclotron absorption of high-frequency waves are frequently brought into models devoted to coronal heating and fast solar-wind acceleration. Signatures of ion-cyclotron resonance have already been observed in situ in the solar wind (HELIOS spacecrafts) and, recently, in the upper corona (UVCS/SOHO remote-sensing resul…
XMM-Newton observations of the diffuse X-ray emission in the starburst galaxy NGC 253
Pietsch, W.; Read, A. M.; Freyberg, M. J. +4 more
Aims: We present a study of the diffuse X-ray emission in the halo and the disc of the starburst galaxy NGC 253.
Methods: After removing point-like sources, we analysed XMM-Newton images, hardness ratio maps and spectra from several regions in the halo and the disc. We introduce a method to produce vignetting corrected images from the EPIC pn …
Modelling the Venusian airglow
Leblanc, F.; Gronoff, G.; Lilensten, J. +3 more
Context: Modelling of the Venusian ionosphere fluorescence is required, to analyse data being collected by the SPICAV instrument onboard Venus Express.
Aims: We present the modelling of the production of excited states of O, CO and N2, which enables the computation of nightglow emissions. In the dayside, we compute several emissions, taking ad…
Supergranules over the solar cycle
Meunier, N.; Roudier, T.; Rieutord, M.
Context: The origin of supergranulation has not been understood yet. Contradictory results have been obtained in the past concerning the relation between supergranule properties (mostly cell size) and the solar cycle.
Aims: We propose to study the variation in supergranule cell sizes and velocity fields over the solar cycle, as well as the int…
Simultaneous absolute timing of the Crab pulsar at radio and optical wavelengths
Schulz, R.; Oosterbroek, T.; Golden, A. +7 more
Context: The Crab pulsar emits across a large part of the electromagnetic spectrum. Determining the time delay between the emission at different wavelengths will allow to better constrain the site and mechanism of the emission. We have simultaneously observed the Crab Pulsar in the optical with S-Cam, an instrument based on Superconducting Tunneli…
The directivity of solar type III bursts at hectometer and kilometer wavelengths: Wind-Ulysses observations
Maksimovic, M.; Bonnin, X.; Hoang, S.
We investigate the directivity of solar type III radio bursts at hectometer and kilometer wavelengths using radio data recorded simultaneously by the Wind and Ulysses spacecraft which are widely separated in heliocentric longitude and latitude. From the positions of the associated flares and the solar wind speed and plasma density measured aboard …
An intense state of hard X-ray emission of Cyg X-1 observed by INTEGRAL coincident with TeV measurements
Malzac, J.; Laurent, P.; Cadolle Bel, M. +3 more
Aims: We present INTEGRAL light curves and spectra of the black-hole binary Cyg X-1 during a bright event that occurred in 2006 September, and which was simultaneous with a detection at 0.15-1 TeV energies by the MAGIC telescope.
Methods: We analyse the hard X-ray emission from 18 to 700 keV with the INTEGRAL data taken on 2006 September 24-26…
An intriguing solar microflare observed with RHESSI, Hinode, and TRACE
Krucker, S.; Lin, R. P.; Hannah, I. G. +2 more
Aims:We investigate particle acceleration and heating in a solar microflare.
Methods: In a microflare with non-thermal emission to remarkably high energies (>50 keV), we investigate the hard X-rays with RHESSI imaging and spectroscopy and the resulting thermal emission seen in soft X-rays with Hinode/XRT and in EUV with TRACE.
Results: …
Integral-field spectroscopy of a Lyman-break galaxy at z = 3.2: evidence for merging
Verma, A.; Davies, R. I.; Eisenhauer, F. +2 more
We present spatially-resolved, rest-frame optical spectroscopy of a z∼ 3 Lyman-break galaxy (LBG), Q0347-383 C5, obtained with SINFONI on the VLT. This galaxy, among the ∼ 10% brightest LBGs, is only the second z∼ 3 LBG observed with an integral-field spectrograph. It was first described by Pettini et al. (2001, ApJ, 554, 981), who obtained WFPC2 …
Swift follow-up observations of INTEGRAL sources of unknown nature
Chaty, S.; Tomsick, J. A.; Rodriguez, J.
Context: Since its launch in 2002, INTEGRAL has discovered many new hard X-ray sources. A lot of them still lack sufficient positional accuracy, for finding counterparts at other wavelengths. Their true nature is, therefore, still unknown.
Aims: The goal of this study is to give an accurate X-ray position for 12 of these sources so as to furth…