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Using Weak-Lensing Dilution to Improve Measurements of the Luminous and Dark Matter in A1689
Broadhurst, Tom; Kong, Xu; Coe, Dan +6 more
The E/S0 sequence of a cluster defines a boundary redward of which a reliable weak-lensing signal can be obtained from background galaxies, uncontaminated by cluster members. For bluer colors, both background and cluster members are present, reducing the average distortion signal by the proportion of unlensed cluster members. In deep Subaru and HS…
Spectacular Shells in the Host Galaxy of the QSO MC2 1635+119
Schweizer, François; Lacy, Mark; Stockton, Alan +4 more
We present deep HST ACS images and Keck spectroscopy of MC2 1635+119, a QSO hosted by a galaxy previously classified as an undisturbed elliptical galaxy. Our new images reveal dramatic shell structure indicative of a merger event in the relatively recent past. The brightest shells in the central regions of the host are distributed alternately in r…
Substructure in lensing clusters and simulations
Springel, Volker; Natarajan, Priyamvada; De Lucia, Gabriella
We present high-resolution mass reconstructions for five massive cluster-lenses spanning a redshift range from z = 0.18 to 0.57 utilizing archival Hubble Space Telescope data and applying galaxy-galaxy lensing techniques. These detailed mass models were obtained from the observations by combining constraints from the strong and weak lensing regime…
Understanding the escape of water from Enceladus
Johnson, R. E.; Sittler, E. C.; Smith, H. T. +3 more
On 14 July 2005, Cassini passed within 175 km of Enceladus' surface enabling a direct in situ measurement of water escaping from the surface by the Ion and Neutral Mass Spectrometer (INMS) and the observation of a stellar occultation by the Ultraviolet Spectrometer (UVIS). We have developed a three-dimensional, Monte Carlo neutral model to simulta…
Kink-induced Catastrophe in a Coronal Eruption
Liu, Rui; Alexander, David; Gilbert, Holly R.
We investigate the kinking motion and its role in the eruption of a filament/cavity system that occurred on 2002 October 31. The evolution of the eruptive filament consists of four distinct phases. After an initial slow upward acceleration, the filament experiences a quasi-static phase exhibiting kinking motions of the filament axis. The kinking p…
Minor ions in the solar wind
Bochsler, Peter
Ions heavier than 4He are treated as “minors” in the solar wind. This is justified for many applications since minor ions have no significant influence on the dynamics of the interplanetary plasma. However, minor ions carry information on many aspects of the formation, on the acceleration and on the transfer of solar plasma from the cor…
The Blue Straggler Population of the Globular Cluster M5
Dalessandro, E.; Beccari, G.; Ferraro, F. R. +5 more
By combining high-resolution HST and wide-field ground-based observations, in ultraviolet and optical bands, we study the blue straggler star (BSS) population of the galactic globular cluster M5 (NGC 5904) from its very central regions up to its periphery. The BSS distribution is highly peaked in the cluster center, decreases at intermediate radii…
Discovery of the Narrow-Line Seyfert 1 Galaxy Markarian 335 in a Historical Low X-Ray Flux State
Gallo, Luigi C.; Grupe, Dirk; Komossa, Stefanie
We report the discovery of the narrow-line Seyfert 1 galaxy Mrk 335 in an extremely low X-ray state. A comparison of Swift observations obtained in 2007 May and June/July with all previous X-ray observations between 1971 and 2006 show the AGN to have diminished in flux by a factor of more than 30, the lowest X-ray flux Mrk 335 has ever been observ…
Probing the Disk-Jet Connection of the Radio Galaxy 3C 120 Observed with Suzaku
Isobe, Naoki; Takahashi, Tadayuki; Tashiro, Makoto S. +13 more
We report on deep (40ks × 4) observations of the bright broad line radio galaxy 3C 120 using Suzaku. The observations were spaced one week apart, and sampled a range of continuum fluxes. An excellent broadband spectrum was obtained over two decades of frequency (0.6 to 50keV) within each 40ks exposure. We clearly resolved the iron K emission-line …
Magnetic fields in planetary nebulae and post-AGB nebulae
Sabin, L.; Greaves, J. S.; Zijlstra, Albert A.
Magnetic fields are an important but largely unknown ingredient of planetary nebulae. They have been detected in oxygen-rich asymptotic giant branch (AGB) and post-AGB stars, and may play a role in the shaping of their nebulae. Here we present SCUBA submillimetre polarimetric observations of four bipolar planetary nebulae and post-AGB stars, inclu…