Search Publications
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…
Diffuse stellar emission in X-ray luminous galaxy clusters at z ~ 0.3. I. Is the diffuse optical light boosted and rejuvenated in merging clusters?
Zhang, Y. -Y.; Finoguenov, A.; Böhringer, H. +4 more
Context: Clusters of galaxies host a diffuse population of intergalactic stars. Diffuse optical light is observed in clusters up to redshift z ∼ 0.4. Recent cosmological hydrodynamical simulations show that this intracluster light originates nearly in parallel with the build-up of the brightest cluster galaxy (BCG), as identified at z=0. However, …
Very Large Array Limits for Intermediate-Mass Black Holes in Three Globular Clusters
Gebhardt, K.; Goss, W. M.; Bash, F. N. +1 more
The observational evidence for central black holes in globular clusters has been argued extensively, and their existence has important consequences for both the formation and evolution of the cluster. Most of the evidence comes from dynamical arguments, but the interpretation is difficult, given the short relaxation times and old ages of the clust…
Cluster observations of electrostatic solitary waves near the Earth's bow shock
RèMe, H.; André, M.; Krasnoselskikh, V. +8 more
Using a period of internal burst mode data from the Cluster Electric Field and Wave instrument a number of electrostatic solitary structures have been identified in the foot region of Earth's quasi-perpendicular bow shock. The four individual probe potential measurements are utilized to investigate the fundamental characteristics of the solitary w…
Physical parameters along the boundaries of a mid-latitude streamer and in its adjacent regions
Susino, R.; Landi, E.; Spadaro, D. +2 more
Context: Coronal streamers appear to be strictly associated with the generation of the slow solar wind, even if a firm identification of the sources of the particle flux within these structures is still an unresolved issue.
Aims: The purpose of this work is to contribute to a better knowledge of the physical characteristics of streamers and of…
An Ultraluminous Supersoft X-Ray Source in M81: An Intermediate-Mass Black Hole?
Liu, Jifeng; Di Stefano, Rosanne
Ultraluminous supersoft X-ray sources (ULSSSs) exhibit supersoft spectra with blackbody temperatures of 50-100 eV and bolometric luminosities above 1039 ergs s-1 and are possibly intermediate-mass black holes (IMBHs) of >=103 M⊙ or massive white dwarfs that are progenitors of Type Ia supernovae. In th…
The Nature and Geometry of the Light Echo from SN 2006X
Crotts, Arlin P. S.; Yourdon, David
We report on the discovery of the geometry producing the light echo emanating from supernova 2006X, a nearby but underluminous Type Ia supernova (SN Ia) in M100 (=NGC 4321). This offers a rare chance to study the environment of a SN Ia. Contrary to previous reports, there is little evidence of a circumstellar component in the light echo morphology…
Photometric and spectral analysis of the distribution of crystalline and amorphous ices on Enceladus as seen by Cassini
Brown, R. H.; Buratti, B. J.; Jaumann, R. +3 more
Photometric and spectral analysis of data from the Cassini Visual and Infrared Mapping Spectrometer (VIMS) has yielded significant results regarding the properties and composition of the surface of Saturn's satellite Enceladus. We have obtained spectral cubes of this satellite, containing both spatial and spectral information, with a wavelength di…