Search Publications
High Resolution WFPC2 Imaging of IRAS 09104 + 4109
Armus, L.; Soifer, B. T.; Neugebauer, G.
With a infrared luminosity of nearly 10^13 Lsuns, IRAS 09104+4109 is the most luminous galaxy with z<0.5 in the IRAS All Sky Survey. A radio-loud Seyfert 2 type optical spectrum, a cD host galaxy in a rich cluster, and a massive cooling flow make IRAS 09104+4109 unique among ultraluminous infrared galaxies. Cannibalized cluster members and the …
Interplanetary Pick-Up Ion Acceleration A Study of Anisotropic Phase-Space Diffusion
Fahr, H. J.; Chalov, S. V.
Interplanetary pick-up ions originate from ionizations of neutral interstellar atoms in the heliosphere. Over the past periods it was generally expected that after pick-up by the frozen-in solar wind magnetic fields these ions quickly isotropize in velocity space by strong pitch- angle scattering, they do, however, not assimilate to the ambient so…
Kinematics of nearby Subdwarfs
Wielen, R.; Jahreiss, H.; Fuchs, B.
A sample of subdwarfs with accurate space velocities and standarized metallicities is presented. This was constructed by combining Hipparcos parallaxes and proper motions with radial velocities and metallicities from Carney et al. (1994; CLLA). The accurate Hipparcos parallaxes lead to an – upward – correction factor of 11% of the photometric dist…
Young and Old Galaxies at High Redshift
Windhorst, R.; Waddington, I.; Cohen, S. +2 more
We review the results from recent deep HST imaging on faint galaxies. Artificial Neural Networks (ANNs) were used to classify faint galaxies based on surface brightness and light profiles. We use available UV + ground-basedU-band images of nearby galaxies to address the effects from the uncertain red shifted UV-morphology on the classifications, r…
Old, Low-Mass, Metal-Rich (SMR) Stars
Soubiran, C.; Lebreton, Y.; Cayrel de Strobel, G. +1 more
The authors of this paper try to disentangle the many problems arisen from a new enlarged sample of nearby low-mass,metal-rich-stars. These stars have reliable absolute magnitudes, deduced from Hipparcos parallaxes, precise bolometric corrections, effective temperatures and metal abundances from high resolution detailed spectroscopic analyses. The…
ISOCAM cosmological Surveys
Aussel, H.; Elbaz, D.; Cesarsky, C. J.
Several deep surveys have been performed at 7 and 15 µm by using the mid-infrared camera ISOCAM on board the ISO satellite. We review their first results, emphasizing on the excess detected in the 15 µm counts with respect to the predictions of models with a mild evolution that is sufficient to explain the IRAS counts. We point out tha…
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…
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 …
Faint Stars and the Structure of the Galaxy
Wolf, C.; Meisenheimer, K.; Jahreiss, H. +2 more
Coronal Holes Versus Normal Quiet Sun Observed with SUMER
Solanki, S. K.; Wilhelm, K.; Brković, A. +5 more
We present a preliminary analysis of spectral lines obtained with the SUMER instrument (Solar Ultraviolet Measurements of Emitted Radiation) onboard the Solar and Heliospheric Observatory (SOHO), as observed during three observing campaigns. From the 70 observed spectral lines, we selected 12, representing 9 ions or atoms, in order to analyse line…