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The Shape of Cas A
Wheeler, J. Craig; Maund, Justyn R.; Couch, Sean M.
On the basis of optical, IR, and X-ray studies of Cas A, we propose a geometry for the remnant based on a "jet-induced" scenario with significant systematic departures from axial symmetry. In this model, the main jet axis is oriented in the direction of strong blueshifted motion at an angle of 110°-120° east of north and about 40°-50° to the east …
Spatial Distribution of Magnetic Reconnection in the 2006 December 13 Solar Flare as Observed by Hinode
Jing, Ju; Wang, Haimin; Chae, Jongchul
A massive two-ribbon flare and its source magnetic field region were well captured by the Solar Optical Telescope (SOT) on board Hinode in the Ca II H spectral line and by the Spectro-Polarimeter of SOT, respectively. Using the high-resolution Hinode data sets, we compare the spatial distribution of the local magnetic reconnection rate and the ene…
The properties of Titan's surface at the Huygens landing site from DISR observations
Keller, H. U.; Küppers, M.; Schröder, S. E. +3 more
The descent imager/spectral radiometer (DISR) onboard the Huygens probe investigated the radiation balance inside Titan's atmosphere and took hundreds of images and spectra of the ground during the descent. The scattering of the aerosols in the atmosphere and the absorption by methane strongly influence the irradiation reaching the surface and the…
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 …
Heterogeneous solid/gas chemistry of organic compounds related to comets, meteorites, Titan, and Mars: Laboratory and in lower Earth orbit experiments
Szopa, C.; Cottin, H.; Coll, P. +14 more
To understand the evolution of organic molecules involved in extraterrestrial environments and with exobiological implications, many experimental programs in the laboratory are devoted to photochemical studies in the gaseous phase as well as in the solid state. The validity of such studies and their applications to extraterrestrial environments ca…
Suprathermal electron evolution in a Parker spiral magnetic field
Owens, M. J.; Crooker, N. U.; Schwadron, N. A.
Suprathermal electrons (>70 eV) form a small fraction of the total solar wind electron density but serve as valuable tracers of heliospheric magnetic field topology. Their usefulness as tracers of magnetic loops with both feet rooted on the Sun, however, most likely fades as the loops expand beyond some distance owing to scattering. As a first …
On the detection of the progenitor of the type Ia supernova 2007on
Bassa, Cees; Nelemans, Gijs; Voss, Rasmus +1 more
We present new Chandra X-ray observations and detailed astrometry of the field of the type Ia supernova 2007on, for which the detection of a likely progenitor in archival Chandra data was recently reported.
No source is detected in the new Chandra images, taken six weeks after optical maximum. We calculate a 90-99 per cent probability that an…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…
A Catalog of Outer Ejecta Knots in the Cassiopeia A Supernova Remnant
Fesen, Robert A.; Hammell, Molly C.
Hubble Space Telescope images of the core-collapse supernova remnant Cassiopeia A are used to identify high-velocity knots of ejecta located outside the remnant's main emission shell of expanding debris. These ejecta fragments are found near or ahead of the remnant's forward shock front and mostly lie from 120'' to 300'' in r…
Molecular hydrogen in the circumstellar environments of Herbig Ae/Be stars probed by FUSE
Deleuil, M.; Bouret, J. -C.; Roberge, A. +7 more
Context: Molecular hydrogen (H2) gas is the most abundant molecule in the circumstellar (CS) environments of young stars. It is thus a key element in our understanding of the evolution of pre-main sequence stars and their environments towards the main sequence.
Aims: At the present time, little is known about the gas as compared to the dust in…