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Anatomy of a young massive star cluster: NGC 1569-B
Larsen, S. S.; Gallagher, J. S.; Origlia, L. +1 more
We present new H-band echelle spectra, obtained with the NIRSPEC spectrograph at Keck II, for the massive star cluster `B' in the nearby dwarf irregular galaxy NGC 1569. From spectral synthesis and equivalent width measurements, we obtain abundances and abundance patterns. We derive an Fe abundance of [Fe/H] = -0.63 +/- 0.08, a supersolar [α/Fe] a…
Discontinuity in Jupiter's main auroral oval
Krupp, N.; Woch, J.; Bonfond, B. +3 more
On the basis of a series of FUV Hubble Space Telescope images obtained between 1997 and 2007 it is shown that there is a segment of the main auroral oval where the emission drops significantly from a few hundreds to a few tens of kiloRayleigh, forming a discontinuity in the oval. It is shown that the discontinuity is present in both hemispheres an…
Structural parameters for globular clusters in NGC 5128 - III. ACS surface brightness profiles and model fits
Forbes, Duncan A.; Barmby, Pauline; Harris, William E. +2 more
We present internal surface brightness profiles, based on Hubble Space Telescope/ACS imaging in the F606W bandpass, for 131 globular cluster (GC) candidates with luminosities L ~= 104-3 × 106Lsolar in the giant elliptical galaxy NGC 5128. Several structural models are fitted to the profile of each cluster and combi…
2 Years of INTEGRAL Monitoring of GRS 1915+105. I. Multiwavelength Coverage with INTEGRAL, RXTE, and the Ryle Radio Telescope
Belloni, T.; Rodriguez, J.; Cadolle Bel, M. +13 more
We report the results of simultaneous monitoring observations of the Galactic microquasar GRS 1915+105 with INTEGRAL and RXTE from 3 up to ~300 keV, and the Ryle Telescope at 15 GHz. We first identify the classes of variability in which GRS 1915+105 is found, and report some direct transitions between them. The accretion ejection connections are s…
Metallicity-corrected Tip of the Red Giant Branch Distance to NGC 4258
Madore, Barry F.; Freedman, Wendy L.; Mager, Violet A.
We have determined the distance to NGC 4258 using observations made with the Hubble Space Telescope (HST) and the Wide Field, Advanced Camera for Surveys (ACS WFC). We apply a modified technique that fully accounts for metallicity effects on the use of the luminosity of the tip of the red giant branch (TRGB) to determine one of the most precise TR…
The determination of the structure of Saturn's F ring by nearby moonlets
Charnoz, Sébastien; Murray, Carl D.; Beurle, Kevin +3 more
Saturn's narrow F ring exhibits several unusual features that vary on timescales of hours to years. These include transient clumps, a central core surrounded by a multistranded structure and a regular series of longitudinal channels associated with Prometheus, one of the ring's two `shepherding' satellites. Several smaller moonlets and clumps have…
Ejecta, Dust, and Synchrotron Radiation in SNR B0540-69.3: A More Crab-Like Remnant than the Crab
Blair, William P.; Reynolds, Stephen P.; Points, Sean +10 more
We present near- and mid-infrared observations of the pulsar-wind nebula (PWN) SNR B0540-69.3 and its associated supernova remnant made with the Spitzer Space Telescope. We report detections of the PWN with all four IRAC bands, the 24 µm band of MIPS, and the Infrared Spectrograph (IRS). We find no evidence of IR emission from the X-ray/radi…
Magnetic Interaction: A Transequatorial Jet and Interconnecting Loops
Yang, Jiayan; Wang, Jingxiu; Shen, Yuandeng +2 more
We present, to our knowledge for the first time, a rare observation of direct magnetic interaction between a transequatorial jet and interconnecting loops (IL) in the southern hemisphere. The jet originated from a flare and appeared to move outward along open field lines, but it passed so close to the IL that its edge met with one of the IL ends. …
Venus Express observes a new type of shock with pure kinematic relaxation
Zhang, T. L.; Balikhin, M. A.; Gedalin, M. +2 more
Collisionless shocks are present in the vicinity of many astrophysical objects such as supernova remnants, space jets, stars and planets immersed in the supersonic flow of stellar winds. Understanding the shock structure is crucial for understanding the processes of the redistribution of the upstream flow energy into accelerated particles and form…
X-Ray-emitting Ejecta in Puppis A Observed with Suzaku
Petre, Robert; Hwang, Una; Flanagan, Kathryn A.
We report the detection and localization of X-ray-emitting ejecta in the middle-aged Galactic supernova remnant Puppis A using five observations with the Suzaku X-Ray Imaging Spectrometer to survey the eastern and middle portions of the remnant. A roughly 3' × 5', double-peaked region in the north center is found to be highly enriched in Si and ot…