Search Publications
Long-term variability of the Be/X-ray binary A0535+26 - I. Optical and UV spectroscopy
Coe, M. J.; Steele, I. A.; Buckley, D. A. H. +11 more
The results of a 7-yr optical and UV spectroscopic study of the high-mass X-ray binary A0535+26 are presented. It was found that throughout the period of the observations the line profile of Hα showed considerable variability. A correlation between the equivalent width of Hα and both V-band magnitude and (B-V) colour excess was observed, albeit wi…
Cosmic-Ray Transport Coefficients
Giacalone, Joe
A review of cosmic-ray transport coefficients, based on historic and recent observations and theoretical insights, is presented. Particular emphasis is on the transport of cosmic rays across the magnetic field, which is of foremost importance, and is presently poorly understood and widely debated.
Detection of Far-Infrared Water Vapor, Hydroxyl, and Carbon Monoxide Emissions from the Supernova Remnant 3C 391
Reach, William T.; Rho, Jeonghee
We report the detection of shock-excited far-infrared emission of H2O, OH, and CO from the supernova remnant 3C 391, using the Infrared Space Observatory Long-Wavelength Spectrometer. This is the first detection of thermal H2O and OH emission from a supernova remnant. For two other remnants, W28 and W44, CO emission was detec…
The Lensing Cluster MS 0440+0204 Seen by HST, ROSAT, and ASCA. I. Cluster Properties
Le Fèvre, O.; Hammer, F.; Falco, E. E. +3 more
We present an analysis of the properties of the lensing cluster MS 0440+0204 at z = 0.1965. MS 0440+0204 has been observed with a variety of telescopes at diverse wavelengths: from the ground with the Canada-France-Hawaii Telescope, the Multiple Mirror Telescope, and the Keck Telescope, and from the Earth orbit with HST, ROSAT, and ASCA. Mass dete…
Energetic (∼ 1 to 50 MeV) protons associated with Earth-directed coronal mass ejections
Laitinen, T.; Vainio, R.; Valtonen, E. +7 more
During the period from January through mid-May, 1997, four large Earth-directed CMEs were observed by the Large Angle Spectroscopic Coronograph (LASCO). These CMEs were associated with long-lasting fluxes of >1.6 MeV protons detected by the Energetic and Relativistic Nuclei and Electron instrument (ERNE). However, the magnitudes of energetic pr…
Evidence for low-level AGN activity in the nucleus of the LINER galaxy NGC4594
Filippenko, A. V.; Ho, L. C.; Reichert, G. A. +4 more
We investigate the properties of the low-ionization nuclear emission-line region (LINER) galaxy, NGC4594, using data taken with the Faint Object Spectrograph on the Hubble Space Telescope (HST) and with the ASCA X-ray observatory. The ultraviolet spectrum shows only narrow-line emission (FWHM ~800-1000 km s^-1) with no evidence for broad emission-…
The nature of isolated T Tauri stars
Henning, Thomas; Hoff, Wilhelm; Pfau, Werner
We present the results of a search for young stellar objects around the two isolated T Tauri stars (TTSs) TW Hya and CoD-29degr 8887. From the spectroscopic properties of these two objects, it is obvious that they are T Tauri stars, although they are not associated with a star-forming region as it is the case for most of the known TTSs. Especially…
Unveiling the nature of the Cloverleaf lens-system: HST/NICMOS-2 observations
Kneib, J. -P.; Alloin, D.; Pello, R.
We present new elements in the identification of the Cloverleaf lens-system based on recent NICMOS-2/F160W observations. After a careful PSF subtraction of the 4 images of the quasar, the residual HF160W image reveals the presence of a faint object (H ~ 20.5) amid the 4 quasars. This object corresponds to a single galaxy that we identif…
Photometric Evolution of Galaxies in Cosmological Scenarios
Steinmetz, Matthias; Contardo, Gertrud; Fritze-von Alvensleben, Uta
The photometric evolution of galaxies in a hierarchically clustering universe is investigated. The study is based on high-resolution numerical simulations that include the effects of gasdynamics, shock heating, radiative cooling, and a heuristic star formation scheme. The outcome of the simulations is convolved with photometric models, which enabl…
Radial heliospheric magnetic fields detected by Ulysses
Balogh, A.; Jones, G. H.; Forsyth, R. J.
The magnetometer aboard the Ulysses spacecraft has recorded numerous examples of heliospheric magnetic fields orientated in near-radial directions for periods of several hours or more. These fields are unusual, as their existence is contrary to the predictions of classical theories concerning solar wind production and propagation. The magnetic fie…