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The extended Hα-emitting filaments surrounding NGC 4696, the central galaxy of the Centaurus cluster
Fabian, A. C.; Sanders, J. S.; Crawford, C. S. +1 more
We present images of NGC 4696, the central galaxy in the Centaurus cluster, showing the large extent of cool filaments that are bright in Hα line emission. These filaments share the detailed structure of both the central dust lane and the inner regions of the arc-like plumes seen in soft X-ray emission. The X-ray gas is at its coolest and most abs…
Three XMM-Newton observations of the anomalous X-ray pulsar 1E 1048.1-5937: Long term variations in spectrum and pulsed fraction
Tiengo, A.; Mereghetti, S.; Stella, L. +4 more
We report the results of a recent (July 2004) XMM-Newton Target of Opportunity observation of the Anomalous X-ray Pulsar 1E 1048.1-5937 together with a detailed re-analysis of previous observations carried out in 2000 and 2003. In July 2004 the source had a 2-10 keV flux of 6.2 × 10-12 erg cm-2 s-1 and a pulsed fra…
The Hubble constant from the gravitational lens CLASS B0218+357 using the Advanced Camera for Surveys
Jackson, N.; Browne, I. W. A.; York, T. +2 more
We present deep optical observations of the gravitational lens system CLASS B0218+357, from which we derive an estimate for the Hubble constant (H0). Extensive radio observations using the VLA, MERLIN, the VLBA and VLBI have reduced the degeneracies between H0 and the mass model parameters in this lens to one involving only t…
Cloud Structure and Physical Conditions in Star-forming Regions from Optical Observations. II. Analysis
Andersson, B. -G.; Federman, S. R.; Sheffer, Y. +1 more
To complement the optical absorption line survey of diffuse molecular gas in Paper I, we obtained and analyzed far-ultraviolet H2 and CO data on lines of sight toward stars in Cep OB2 and Cep OB3. Possible correlations between column densities of different species for individual velocity components, not total columns along a line of sig…
The XMM-Newton view of Mrk 3 and IXO 30
Fabian, Andrew C.; Bianchi, Stefano; Miniutti, Giovanni +1 more
We present the analysis of the XMM-Newton European Photon Imaging Camera (EPIC) pn spectrum of the Seyfert 2 galaxy Mrk 3. We confirm that the source is dominated by a pure Compton reflection component and an iron Kα line, both produced as a reflection from a Compton-thick torus, likely responsible also for the large column density (1.36+0.03…
Discovery of a Nearly Edge-on Disk around HD 32297
Schneider, Glenn; Hines, Dean C.; Silverstone, Murray D.
We report the discovery of a nearly edge-on disk about the A0 star HD 32297 seen in light scattered by the disk grains revealed in NICMOS PSF-subtracted coronagraphic images. The disk extends to a distance of at least 400 AU (3.3") along its major axis with a 1.1 µm flux density of 4.81 +/- 0.57 mJy beyond a radius of 0.3" from the coronagra…
XMM-Newton Observations of Evolution of Cluster X-Ray Scaling Relations at z=0.4-0.7
Vikhlinin, A.; Kotov, O.
We present a spatially resolved analysis of the temperature and gas density profiles of galaxy clusters at z=0.4-0.7 observed with XMM-Newton. These data are used to derive the total cluster mass within the radius r500 without assuming isothermality and also to measure the average temperature and total X-ray luminosity, excluding the co…
A Study of Edge-On Galaxies with the Hubble Space Telescope Advanced Camera for Surveys. I. Initial Results
de Jong, Roelof S.; Seth, Anil C.; Dalcanton, Julianne J.
We present the initial results of a Hubble Space Telescope/Advanced Camera for Surveys snapshot survey of 16 nearby, edge-on, late-type galaxies covering a range in distance from 2 to 19 Mpc. The images of these galaxies show significant resolved stellar populations. We derive F606W and F814W photometry for more than 1.2 million stars and present …
Origin of the Marsden and Kracht Groups of Sunskirting Comets. I. Association with Comet 96P/Machholz and Its Interplanetary Complex
Sekanina, Zdenek; Chodas, Paul W.
Of the three major groups of comets approaching the Sun to between 6 and 12 solar radii and discovered with the coronagraphs on board SOHO, we investigate the Marsden and Kracht groups. We call these comets ``sunskirters'' to distinguish them from the Kreutz system sungrazers. Our objective is to understand the origin, history, and orbital evoluti…
Identifying Lenses with Small-Scale Structure. II. Fold Lenses
Keeton, Charles R.; Gaudi, B. Scott; Petters, A. O.
When the source in a four-image gravitational lens system lies sufficiently close to a ``fold'' caustic, two of the lensed images lie very close together. If the lens potential is smooth on the scale of the separation between the two close images, the difference between their fluxes should approximately vanish, Rfold≡(F+-F