Search Publications
The Role of Nuclear Starbursts in Luminous Infrared Seyfert 2 Galaxies
Heckman, Timothy; González Delgado, Rosa M.
We present HST (WFPC2 and FOC) images and UV GHRS spectra plus ground-based optical spectra of four Luminous Infrared Galaxies (LIRGs) that have Seyfert 2 nuclei (Mrk 477, NGC 7130, NGC 5135 and IC 3639). The data provide direct evidence of the existence of a central nuclear starburst that dominates the UV and optical light and are dusty and compa…
Understanding the atmospheric structure of T Tauri stars - I. Improved atomic physics applied to IUE data of BP Tauri
Lanzafame, A. C.; Brooks, D. H.; Costa, V. M. +1 more
Recent advances in modelling the radiating character of dynamic laboratory and astrophysical plasmas are applied here in a new examination of the properties of the atmosphere of the classical T Tauri star BP Tau. We analyse archived International Ultraviolet Explorer (IUE) UV spectra of BP Tau. We adopt a collisional-radiative model and utilize em…
Low frequency plasma turbulence and high energy particles at CIR-related shock waves
Claßen, H. -T.; Mann, G.; Forsyth, R. J. +1 more
We present initial results from a survey of the low frequency magnetic field turbulence measured at the forward/reverse shock pairs associated with the interaction regions of high and low speed solar wind streams (CIRs). The magnetic field data are taken from vector helium and fluxgate magnetometer observations (VHM/FGM) aboard the Ulysses spacecr…
Atomic silicon towards the Orion-KL nebula
Walmsley, C. M.; Pineau des Forêts, G.; Gry, C.
We have used the Long Wavelength Spectrometer (LWS) on board ISO to observe the fine structure lines of atomic silicon at 68.5 and 129.7 microns towards the Orion Kleinmann-Low nebula. Our data show evidence for the detection of the J=2-1 transition at 68.5mum with a signal-to-noise ratio of 5. We consider the formation of the observed emission li…
Evidence for Advective Flow from Multiwavelength Observations of Nova MUSCAE
Misra, Ranjeev
We model the UV/optical spectrum of the black hole binary Nova Muscae as a sum of blackbody emissions from the outer region of an accretion disk. We show for self-consistency that scattering effects in this region are not important. The black hole mass (M~6 Msolar), the inclination angle (µ~0.5), and the distance to the source (D~…
Soft X-ray properties of Ultraluminous IRAS Galaxies
Boller, Th.
A sample of 323 Ultraluminous IRAS galaxies (ULIRGs) has been correlatedwith the ROSAT All-Sky Survey and ROSAT public pointed observations.22 objects are detected in ROSAT survey observations, and 6 ULIRGs aredetected in addition in ROSAT public pointed observations. The detection is basedon a visual inspection of the X-ray contour maps overlaid …
A Path Integral Solution to the Stochastic Differential Equation of the Markov Process for Cosmic Ray Transport
Zhang, Ming
Cosmic ray transport in interplanetary or interstellar magnetic fields can be viewed as a Markov stochastic process and the transport equation has therefore recently been reformulated with a set of stochastic differential equations that describe the guiding center and the momentum of individual charged particles. The Fokker-Planck diffusion equati…
The heliospheric Modulation od Cosmic ray Electrons: Rigidity Dependence of the perpendicular Diffusion Coefficient
Ferreira, S. E. S.; Potgieter, M. S.; Heber, B.
The modulation of cosmic ray electrons in the heliosphere provides a useful tool in understanding and estimating the diffusion tensor applicable to heliospheric modulation. Using a comprehensive modulation model including all major mechanisms to study electron modulation, especially at energies below 500 MeV, we found that perpendicular diffusion …
The iron, silicon, and oxygen abundance in the solar wind measured with SOHO/CELIA/MTOF
Wurz, P.; Bochsler, P.; Galvin, A. B. +7 more
Hubble Space Telescope Astrometric Observations of the Metal-poor Spectroscopic Binary HD 20039
Hershey, John L.; Osborn, Wayne
An attempt has been made to spatially resolve the metal-poor, double-lined spectroscopic binary HD 20039 with the Hubble Space Telescope Fine Guidance System. Astrometric measurements of the system to complement the spectroscopic orbit would permit the distance and the masses of the components to be determined. Observations were obtained around th…