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Variable morphology of Saturn's southern ultraviolet aurora
Clarke, J. T.; Cowley, S. W. H.; Bunce, E. J. +2 more
The Space Telescope Imaging Spectrograph camera on board Hubble Space Telescope obtained 68 FUV images of Saturn's southern auroral emission between 8 and 30 January 2004, during Cassini's approach to Saturn's magnetosphere. The HST observations took place in four different solar wind regimes with a low-field rarefaction region from 8 to 16 Januar…
Hubble Space Telescope imaging of the progenitor sites of six nearby core-collapse supernovae
Smartt, S. J.; Maund, J. R.
The search for the progenitors of six core-collapse supernovae (CCSNe) in archival Hubble Space Telescope (HST) WFPC2 pre-explosion imaging is presented. These SNe are 1999an, 1999br, 1999ev, 2000ds, 2000ew and 2001B. Post-explosion imaging of the SNe, with the HST ACS/WFC, has been utilized with the technique of differential astrometry to identif…
The Ionized Gas and Nuclear Environment in NGC 3783. V. Variability and Modeling of the Intrinsic Ultraviolet Absorption
Kaiser, Mary Elizabeth; Brandt, W. N.; Kaspi, Shai +13 more
We present results on the location, physical conditions, and geometry of the outflow in the Seyfert 1 galaxy NGC 3783 from a study of the variable intrinsic UV absorption. Based on analysis of 18 observations with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope and six observations with the Far Ultraviolet Spectroscopi…
The Stellar Populations of the M31 Halo Substructure
Lewis, Geraint F.; Ibata, Rodrigo A.; Johnston, Kathryn V. +5 more
We present the first results from our survey of stellar substructure in the outskirts of M31 using the Advanced Camera for Surveys on board the Hubble Space Telescope. We discuss the stellar populations associated with five prominent stellar overdensities discovered during the course of our panoramic ground-based imaging survey with the Isaac Newt…
Properties of local plasma injections in Saturn's magnetosphere
André, N.; Coates, A. J.; Kurth, W. S. +6 more
Electron and ion drift dispersion events are often observed by the Cassini Plasma Spectrometer (CAPS) in the inner magnetosphere of Saturn (5 to 10 RS). These events appear to result from azimuthally-limited injections of plasma and persist for at least several hours. During this time, the events can be analyzed to obtain information on…
Regularized orbit models unveiling the stellar structure and dark matter halo of the Coma elliptical NGC 4807
Saglia, R. P.; Thomas, D.; Thomas, J. +5 more
This is the second in a series of papers dedicated to unveiling the mass structure and orbital content of a sample of flattened early-type galaxies in the Coma cluster. The ability of our orbit libraries to reconstruct internal stellar motions and the mass composition of a typical elliptical in the sample is investigated by means of Monte Carlo si…
Star-formation in NGC 4038/4039 from broad and narrow band photometry: cluster destruction?
Genzel, R.; Lehnert, M. D.; Mengel, S. +1 more
Accurately determining the star formation history in NGC 4038/4039 - "The Antennae" - is hampered by variable and sometimes substantial extinction. We therefore used near infrared broad- and narrow-band images obtained with ISAAC at the VLT and with SOFI at the NTT to determine the recent star formation history in this prototypical merger. In comb…
Cassini Visual and Infrared Mapping Spectrometer Observations of Iapetus: Detection of CO2
Sotin, C.; Brown, R. H.; Baines, K. H. +26 more
The Visual and Infrared Mapping Spectrometer (VIMS) instrument aboard the Cassini spacecraft obtained its first spectral map of the satellite Iapetus in which new absorption bands are seen in the spectra of both the low-albedo hemisphere and the H2O ice-rich hemisphere. Carbon dioxide is identified in the low-albedo material, probably a…
XMM-Newton observations of Extremely Red Objects and the link with luminous, X-ray obscured quasars
Cimatti, A.; Daddi, E.; Fiore, F. +8 more
We present the results of a deep (about 80 ks) XMM-Newton survey of the largest sample of near-infrared selected Extremely Red Objects (R-K> 5) available to date to KS⪉ 19.2. At the relatively bright X-ray fluxes (F2-10 keV⪆ 4× 10-15 erg cm-2 s-1) and near-infrared magnitude probed by the p…
The star cluster population of M 51. III. Cluster disruption and formation history
Bastian, N.; Gieles, M.; Lamers, H. J. G. L. M. +1 more
In this work we concentrate on the evolution of the cluster population of the interacting galaxy M 51 (NGC 5194), more precisely the timescale of cluster disruption and possible variations in the cluster formation rate. We present a method to compare observed age vs. mass number density diagrams with predicted populations including various physica…