Search Publications
The large-scale shock in the cluster of galaxies Hydra A
Finoguenov, A.; Böhringer, H.; Simionescu, A. +5 more
We analyzed a deep XMM-Newton observation of the cluster of galaxies Hydra A, focusing on the large-scale shock discovered in Chandra images as a discontinuity in the surface brightness. The shock front can be seen both in the pressure map and in temperature profiles in several sectors. We compared the results of a spherically symmetric hydrodynam…
Foreshock compressional boundary
Omidi, N.; Blanco-Cano, X.; Sibeck, D. G.
We employ 2.5-D electromagnetic, hybrid simulations that treat ions kinetically via particle-in-cell methods and electrons as a massless fluid to study the formation and properties of a newly discovered boundary named the foreshock compressional boundary (FCB). This boundary forms in the ion foreshock and is associated with enhanced densities and …
The Quintuplet cluster. I. A K-band spectral catalog of stellar sources
Hamann, W. -R.; Oskinova, L. M.; Liermann, A.
Context: Three very massive clusters are known to reside in the Galactic center region, the Arches cluster, the Quintuplet cluster, and the central parsec cluster, each of them rich in young hot stars. With new infrared instruments, this region is no longer obscured for the observer.
Aims: For understanding these very massive clusters, it is e…
The structures of distant galaxies - II. Diverse galaxy structures and local environments at z = 4-6 implications for early galaxy assembly
Conselice, Christopher J.; Arnold, Jessica
We present an analysis of the structures, sizes, star formation rates and local environmental properties of galaxies at z ~ 4-6 (τuniverse < 2 Gyr), utilizing deep Hubble Space Telescope imaging of the Hubble Ultra Deep Field. The galaxies we study are selected with the Lyman-break drop-out technique, using galaxies which are B-, V- …
HST/STIS observations of the RW Aurigae bipolar jet: mapping the physical parameters close to the source
Ray, T. P.; Eislöffel, J.; Bacciotti, F. +2 more
Context: We present the results of new spectral diagnostic investigations applied to high-resolution long-slit spectra obtained with the Hubble Space Telescope Imaging Spectrograph (HST/STIS) of the jet from the T Tauri star RW Aur.
Aims: Our primary goal is to determine basic physical parameters (electron density ne and electron te…
Revealing the Structure of a Pre-Transitional Disk: The Case of the Herbig F Star SAO 206462 (HD 135344B)
Ménard, F.; Apai, D.; Hamaguchi, K. +23 more
SAO 206462 (HD 135344B) has previously been identified as a Herbig F star with a circumstellar disk with a dip in its infrared excess near 10 µm. In combination with a low accretion rate estimated from Br γ, it may represent a gapped, but otherwise primordial or "pre-transitional" disk. We test this hypothesis with Hubble Space Telescope cor…
Endogenic heat from Enceladus' south polar fractures: New observations, and models of conductive surface heating
Spencer, John R.; Abramov, Oleg
Linear features dubbed "tiger stripes" in the south polar region of Enceladus have anomalously high heat fluxes and are the apparent source of the observed plume. Several explanations for the observed activity have been proposed, including venting from a subsurface reservoir of liquid water, sublimation of surface ice, dissociation of clathrates, …
The extended interacting wind structure of Eta Carinae
Weis, K.; Stahl, O.; Gull, T. R. +9 more
The highly eccentric binary system, η Car, provides clues to the transition of massive stars from hydrogen-burning via the CNO cycle to a helium-burning evolutionary state. The fast-moving wind of η Car B creates a cavity in η Car A's slower, but more massive, stellar wind, providing an in situ probe. The Hubble Space Telescope/Space Telescope Ima…
Current Buildup in Emerging Serpentine Flux Tubes
Aulanier, G.; Masson, S.; Pariat, E.
The increase of magnetic flux in the solar atmosphere during active-region formation involves the transport of the magnetic field from the solar convection zone through the lowest layers of the solar atmosphere, through which the plasma β changes from >1 to <1 with altitude. The crossing of this magnetic transition zone requires the magnetic…
Io's dayside SO 2 atmosphere
Feldman, Paul D.; Feaga, Lori M.; McGrath, Melissa
An extensive set of HI Lyman- α images obtained with the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) from 1997-2001 has been analyzed to provide information about the spatial and temporal character of Io's SO 2 atmosphere. An atmospheric distribution map derived from the observations reveals that the sunlit …