Search Publications
A collimated, high-speed outflow from the dying star V Hydrae
Sahai, R.; Knapp, G. R.; Young, K. +2 more
Stars with masses in the range 1-8 solar masses (M⊙) live ordinary lives for ~109-1010 years, but die extraordinary deaths. First, during their death throes as asymptotic giant branch (AGB) stars they eject, over 104-105 years, half or more of their mass in slowly expanding, spherical winds, a…
The First Detailed Look at a Brown Dwarf Disk
Apai, D.; Pascucci, I.; Henning, Th. +1 more
The combination of mid-infrared and recent submillimeter/millimeter measurements allows us to set up the first comprehensive spectral energy distribution (SED) of the circumstellar material around a young brown dwarf. Simple arguments suggest that the dust is distributed in the form of a disk. We compare basic models to explore the disk parameters…
High-Resolution STIS/Hubble Space Telescope and HIRES/Keck Spectra of Three Weak Mg II Absorbers toward PG 1634+706
Charlton, Jane C.; Churchill, Christopher W.; Rigby, Jane R. +3 more
High-resolution optical (HIRES/Keck) and UV (STIS/Hubble Space Telescope) spectra, covering a large range of chemical transitions, are analyzed for three single-cloud weak Mg II absorption systems along the line of sight toward the quasar PG 1634+706. Weak Mg II absorption lines in quasar spectra trace metal-enriched environments that are rarely c…
High-energy sources before INTEGRAL. INTEGRAL reference catalog
Mowlavi, N.; Courvoisier, T. J. -L.; Bodaghee, A. +2 more
We describe the INTEGRAL reference catalog which classifies previously known bright X-ray and gamma-ray sources before the launch of INTEGRAL. These sources are, or have been at least once, brighter than ~ 1 mCrab above 3 keV, and are expected to be detected by INTEGRAL. This catalog is being used in the INTEGRAL Quick Look Analysis to discover ne…
Extreme galactic wind and Wolf-Rayet features in infrared mergers and infrared quasi-stellar objects
Taniguchi, Y.; Zheng, W.; Terlevich, R. +5 more
We report, as a part of a long-term study of infrared (IR) mergers and IR quasi-stellar objects (QSOs), detailed spectroscopic evidence for outflow (OF) and Wolf-Rayet (WR) features in the nearby mergers NGC4038/39 and IRAS 23128-5919 (with low-velocity OF); and the nearby QSOs IRAS 01003-2238 and 13218+0552 (with extreme velocity OF, EVOF). We al…
Mid-IR spectroscopy of T Tauri stars in Chamealeon I: Evidence for processed dust at the earliest stages
Natta, A.; Meeus, G.; Bouwman, J. +1 more
We present mid-IR spectroscopy of three T Tauri stars in the young Chamealeon I dark cloud obtained with TIMMI2 on the ESO 3.6 m telescope. In these three stars, the silicate emission band at 9.7 mu m is prominent. We model it with a mixture of amorphous olivine grains of different size, crystalline silicates and silica. The fractional mass of the…
The Lack of Observational Evidence for the Quantum Structure of Spacetime at Planck Scales
Turatto, Massimo; Ragazzoni, Roberto; Gaessler, Wolfgang
It has been noted (Lieu & Hillmann) that the cumulative effect of Planck-scale phenomenology, or the structure of spacetime at extremely small scales, can be lead to the loss of the phase of radiation emitted at large distances from the observer. We elaborate on such an approach and demonstrate that such an effect would lead to an apparent blu…
Near-infrared spectroscopy of (proto)-planetary nebulae: molecular hydrogen excitation as an evolutionary tracer
Smith, Michael D.; Davis, Christopher J.; Stern, Luke +2 more
We present an in-depth analysis of molecular excitation in 11 H2-bright planetary and protoplanetary nebulae (PN and PPN). From newly acquired K-band observations, we extract a number of spectra at positions across each source. H2 line intensities are plotted on `column density ratio' diagrams so that we may examine the excit…
On the kinematic evolution of flare-associated cmes
Moon, Y. -J.; Shanmugaraju, A.; Dryer, M. +1 more
We report a common tendency of the kinematic evolution of three flare-associated coronal mass ejections (CMEs). Their kinematic evolutions are examined using well-observed data (eruptive filaments, X-ray structures, and prominences) very close to the solar surface as well as SOHO/LASCO C2-C3 data. Their height-time data are fitted using three anal…
GaBoDS: The Garching-Bonn Deep Survey. I. Anatomy of galaxy clusters in the background of NGC 300
Schirmer, M.; Micol, A.; Schneider, P. +5 more
The Garching-Bonn Deep Survey (GaBoDS) is a virtual 12 square degree cosmic shear and cluster lensing survey, conducted with the WFI@2.2 m MPG/ESO telescope at La Silla. It consists of shallow, medium and deep random fields taken in R-band in subarcsecond seeing conditions at high galactic latitude. A substantial amount of the data was taken from …